Glow discharge editionPrevious thread: >>16233254>What is /ppg/?A thread for discussing plasma physics topics:>General plasma-related questions>Recent papers and developments>Fusion plasmas>Astrophysical plasmas>Low temperature and atmospheric plasmas>Complex/dusty plasmas>Plasma generation and processing>Plasma instrumentation and diagnostics>etc.Contributing papers, discussing research interests, and general effort-posting is encouraged. Suggestions for resources to add to the list are also welcome.
Useful Resources (WIP):General Plasma Physics>Chen, F. Introduction to Plasma Physics and Controlled Fusion>10.1007/978-1-4757-5595-4>Piel, A. Plasma Physics: An Introduction to Laboratory, Space, and Fusion Plasmas>10.1007/978-3-642-10491-6>Gurnett, D. Introduction to Plasma Physics: With Space and Laboratory Applications>10.1017/9781139226059>Conrads, H. & Schmidt, M. Plasma generation and plasma sources>10.1088/0963-0252/9/4/301>Braithwaite, N. Introduction to Gas Discharges>10.1088/0963-0252/9/4/307Fusion>Freidberg, J. Ideal magnetohydrodynamic theory of magnetic fusion systems>10.1103/RevModPhys.54.801>Freidberg, J. Ideal MHD>10.1017/CBO9780511795046Space Plasmas>Baumjohann, W.B. & Treumann, R.A. Basic Space Plasma Physics>doi.org/10.1142/12771>Treumann, R.A. & Baumjohann, W.B. Advanced Space Plasma Physics>10.1142/p020>Tsurutani, B., et al. Space Plasma Physics: A Review>10.1109/TPS.2022.3208906Low Temp., Atmospheric, and Complex Plasmas>Lichtenberg, A. & Lieberman, M.. Principles of Plasma Discharges and Material Processing>10.1002/0471724254>Kong, MG., et al. Plasma medicine: An Introductory Review>10.1088/1367-2630/11/11/115012>Misra, N.N., Schlüter, O., & Cullen, P.J. Cold Plasma in Food and Agriculture>10.1016/C2014-0-00009-3>Merlino, R. Dusty plasmas: from Saturn’s rings to semiconductor processing devices>10.1080/23746149.2021.1873859>Shukla, P. & Mamun, A. Introduction to Dusty Plasma Physics>10.1088/0741-3335/44/3/701Computational Plasma Physics:>Tajima, T. Computational Plasma Physics>10.1201/9780429501470>Jardin, S. Computational Methods in Plasma Physics>10.1201/ebk1439810958Instrumentation and Diagnostics:>Hutchinson, I.H. Principles of Plasma Diagnostics>10.1017/CBO9780511613630>Merlino, R. Understanding Langmuir probe current-voltage characteristics>10.1119/1.2772282>Hershkowitz, N. & Kim, Y.C. Probing plasmas with ion acoustic waves>10.1088/0963-0252/18/1/014018
YouTube Channels and Other Media (WIP):>ITER - Channel for the International Thermonuclear Experimental Reactor project>https://www.youtube.com/@iterorganization>Princeton Plasma Physics Laboratory - Videos and research presentations relating to PPPL projects>https://www.youtube.com/@PPPLab>Institute of Plasma Physics - Some terrific plasma videos from the Czech Academy of Sciences>https://www.youtube.com/@instituteofplasmaphysicsip769>Max Planck Institute for Plasma Physics - Discussions and videos of research, including several on the W7-X stellarator>https://www.youtube.com/@plasmaphysik>University of Sydney - A series of interesting plasma physics lectures>https://www.youtube.com/@usyd-seniorplasmaphysicsle6653>Plasma Channel - Some neat DIY plasma stuff>https://www.youtube.com/@PlasmaChannel
Bump for interest, buy why a general for plasma physics and not physics as a whole?
>>16303577Quality is significantly higher on this topic. The more morons on this board who are unable to contribute here, the better.
>>16303639Makes sense given that half of /sci/ post-2020 are schizos, trannies, /pol/acks, and other assorted tourists.Also out of all the stuff >>16303424 what's the best material to start with for someone with a physics background but hasn't delved into plasma.
congratulations on your second thread, /ppg/.how do you guys think a solid-state/semiconductor general would do on this board?
>>16303705I'm all for it, semiconductor devices and quantum materials were two of my favorite classes
>>16303577It's a good middle ground - not too niche, not too broad. Also, they're neat.>>16303702The book by Chen is a little old (~70s), but it's still a very reliable introductory text. Start there.>>16303705Dunno, but there are quite a few condensed matter posters on /sci/. You might want to explore the idea.
>>16303822>The book by Chen is a little old (~70s)That's not a problem, its not like the introductory stuff will have changed much in 50 years. Besides my one of my profs liked using texts from the 70s anyway.
>>16303423Any recent breakthroughs that I should be aware of in plasma physics?
>>16303871some recent stuff is here https://www.nature.com/subjects/plasma-physics
>>16303871Most recent development I could find comes out of the Madison Symmetric Torus team - they successfully stably operated a tokamak at about ten times the Greenwald limit (the density passed which tokamaks generally become unstable). The previous record for a smaller toroidal device was a little under twice the limit.Good summary at the link below. I'll see if I can't download the paper tomorrow and post it.https://phys.org/news/2024-07-madison-symmetric-torus-stable-plasma.html
>>16304103OK.
>>16304103>was accepted by the journal at the start of the month>still can't get it on sci-hub
>>16304103>>16304719gotcha coveredpretty good read, looks like they were pushing electron densities on the order of 6e19 m-3 - a little over ten times the greenwald limit for that device and operating current, and only a factor of 2-3 less than the densities that ITER is expected to top out at.
>>16304758Thanks for delivering
>>16303423how do I turn a geissler tube into a tube amp, or commission someone to refill a vacuum tube with a metal vapor and phosphor coatings?if the amp portions are between source and drain of the electron flow, all that matters is that the supply/output is properly equipped to work with a longer path
>>16304758I'm confused what are the flux surfaces in this case?
>>16305296The flux surfaces in a fusion device describe the visualized surfaces on which your internal magnetic fields lie. In a tokamak the flux surfaces would basically be little toroidal shells within the plasma.I did some digging and it looks like the MST uses a bunch of interferometers to measure the average density along chords going vertically through a section of the plasma, so I *think* they're saying that the outermost interferometers were just hitting the edges of the plasma.
Thinking about writing some simple guides for these threads - ex. maybe a guide to probe analysis that bullet-points parts of Merlino, Hutchinson, Chen, etc., and talks about some of the practical considerations that have to be taken into account in different experimental regimes.What are some things plasmanons would want to see included in a guide for probes? Or, if not probe stuff, then what are other simple guides that people would find interesting?
>>16305179>refill a vacuum tubelol, good luck with that anon. virtually nobody repairs tubes anymore.
>>16305937>refillI have access to borosilicate tubes and a scientific glassblowing program on campus, I'm looking more at rehousing and modifyinghell, this video shows how it can be done with glassware I have on me right now, outside the pump which probably exists on-sitehttps://youtu.be/dRI0ZLTP6_0I'm looking at the electrical considerations of this as a novice, could a micro triode be combined with a pentode and provide enough power for headphones? What sort of current changes would happen with a drop of mercury or trace xenon in there? How far would stray electrons go past the drain and be able to hit some phosphors, or how long could I set that up with the right power supply to still be used as an amplifier?a long tube that functions as a triode while looking like a geissler tube seems really cool as a long goal project.
>>16305956Is it important that it be functional or or is the goal just to have part of your circuit that makes a neat-looking plasma?If it's the former, I think only practical way to figure out what sort of electronic changes changing your gas composition or things like that would have would be to actually build and test tubes and try stuff out until you find something that works for you. If it's the latter, it'd probably be simpler to just make a basic gas discharge tube and use a transformer to ramp up the voltage on part of your circuit and get a little glow.
>>16306003I'm looking for something that can function as an amp for headphones, so very, very little effective power is needed in the end, your phone probably maxes out at 20-30mw @ 30ohms from the headphonesthe things I'm trying to drive are very low impedance but are paired with headphone amplifiers that could reach 2w @ 30ohms (similarly 200mw @ 300ohm for larger dynamic headphones), to only be wasted by a 0-50k voltage divider on the output being far closer to 50k than 0ohm.For an amplifier, I'm looking for something that's going to need to push a relatively high wattage, but further than like a speaker, suuuper low impedance.What sort of power is going to be needed for a discharge lamp to fully heat up, how will that relate to how much power an input signal will be amplified? Is there an equation or calculator to know the feasibility? I'm here to discuss the dynamics, because I don't know how tube size, material, or distance. I assume I want to waste as much energy to supply in order to get a nice plasma, to the limits of the tube exploding mercury everywhere. Longer distance, but a short path from the grid. The more impedance I have in the tube as long as I have the power supply to keep it going, the better fit for a 20-35ohm load, right? Would metal vapors reduce that impedance? If so, then I could try out trying to push a load across a long tube, as long as the heater wire at the bottom can vaporize the metal. I also have no idea what influences s/n ratios, but I'm not looking for anything high fidelity, just a novelty.I have no sort of context for the Rp value, but I can use boilerplate info or calculate the rest based on existing designs, but what contributes to the impedance. I bet I can find out the values for those mini triodes made in the vid, then play with the scales between a normal triode and the mini to reach the req power at some supply voltage.
>>16305848Writing up a summary of the different regimes would be a good place to start: Collisional vs collisionless plasmas, thick vs thin sheaths, magnetized vs unmagnetized plasmas, etc. How to identify what regime you're in based on the ratios of the different length scales. At the end of the day, most of the actual methods for estimating floating potentials, ion currents, electron temperatures, etc. aren't really that different from one regime to another. The biggest part that changes is just the model or models you use to try and estimate the plasma conditions from those measurements - OML, ABR, BRL, etc. - and the majority of those boil down to just adding different correction factors (magnetized regimes might be the only major exception, that I can think of - magnetic fields just completely fuck Langmuir probe theory).
>>16305848>then what are other simple guides that people would find interesting?how to make your own setup at home for under $1000
>>16306307You want the impossible.
>>16306307not impossible - but definitely depends ona) how much you are capable of and prepared to make on your own andb) what your end goal is - do you just want something you can physically make a plasma with? or do you want something you can do actual experiments on?
In Star Trek they have devices called plasma taps. Which can convert plasma from a fusion reactor directly into electricity. Not to be confused with the devices that utilize plasma directly like replicators or transporters. Given plasma has a positive charge how can you make a device to directly turn this plasma into electricity?
>>16306477I just want a toroid full of glowing purple in my garage how hard could it be
>>16306381NTA, but what do you think is the minimum would need?
why are test fusion reactors so goddamn big?is it not easier to make a smaller reactor, get it to work and then go big?
>>16305956There are a few issues with the manufacturing process in the video. Don’t use tungsten for the leads into the tube. The thermal expansion coefficient is so different from the glass (except for Corning 7720 which isn’t made anymore) that it won’t give a good glass to metal seal and will probably crack due to thermal stresses. Also the brittle tungsten ends up having small fractures that cause gas to leak in through the wire.Try to use kovar for the wires and a matched thermal expansion glass like Corning 7056 or schott 8250. https://www.worldradiohistory.com/BOOKSHELF-ARH/Technology/Technology-Vacuum-Tube/Materials-and-Techniques-for-Electron-Tubes-Wlater-H-Kohl-1960-(657-pages).pdf gives more information about how to properly do the seal.The filament voltage should be gradually ramped up instead of applying it all immediately.Also flash the getter after tipping off the tube from the vacuum pump.I’d recommend against trying to put any gas in the tube since it’s extremely difficult to actually fill it at sufficiently low pressures and anything less than spectroscopically pure would poison the cathode. You’ll probably get enough emission from residual gases left in the tube anyway like in the pic.I have no idea how well that triode would work since I only deal with making microwave frequency tubes
>>16306529>>16307402Depends on what precisely you want to accomplish and how much of the machining/electronics/etc. you're capable of and prepared to do yourself.Standard vacuum parts (KF/ISO/etc) are pricy new, but can be found more affordably on auction sites. Supporting hardware (feedthroughs, seals, clamps, etc.) add up quickly. If you're comfortable with welding, machining, or glasswork you could make some of your own parts.You can get a 2.5 CFM pump from Harbor Freight for $100. It won't support ultra high vacuum, but you can get a low enough base pressure to make a dirty plasma with a lot of air and water vapor left. If you need a lower base pressure you need a bigger pump - larger rotary vane or dry scroll pumps run a couple grand. And unless you're deliberately making an air plasma, you need compressed gas, high purity, argon, neon, helium, etc. You also need regulators and valves to make sure you don't blow up your connections. You also want some kind of pressure monitor/vacuum gauge.If you want a current-limited HVDC supply that'll support a plasma at a few mA, it's gonna be hard finding one, even used, for under a grand. And new DC or RF supplies are super expensive. If you're capable of *safely* building a PSU on your own and are comfortable working with high voltage, you can rig up something for a few hundred bucks, but that carries some risk. If stability isn't an issue, there are some cheap and dirty options - you can harvest the guts out of a plasma lighter or rig up the output of a 555 timer to a little transformer and get a shitty μA plasma going.Instrumentation is another matter (but unnecessary if you're not doing research).A few years ago I put together a demo chamber for my department's annual school expo event: A used ISO-100 six-way cross and some flanges I got from a surplus auction, a power supply I got off eBay and repaired, etc., a pump I "borrowed" from our modern physics lab. Even with all that I was still out about $2500.
>>16307434They know from the math that based on the strength of the magnetic field and other factors that it has to be so big to hit the objectives they want. With older weak magnets you need a very large iter style reactor to even achieve sustainated fusion. Now with the newer magnets it is possible to make smaller chambers. Hence the MIT work.
>>16307529woah!what the fuck is your pic, anon!?!?all I know is it rocks!!
>>16307529Seconding the advice about matching thermal expansion coefficients - mismatched coefficients are like the single biggest reason for not getting good seals or bonds on shit whether it's something messy like a metal-on-glass seal or a tricky weld, or even just basic soldering. Some materials just aren't good matches.
>>16307434A lot of your instabilities in tokamaks come out of asymmetries in geometry - particularly gradients in magnetic field strength on the side of the plasma facing the inner and outer parts of the torus. As you scale up your experiment, those differences get relatively smaller and you can support hotter, denser plasmas with longer confinement times.
/sci/ made it to the round of 16 in this summer's cup, we're playing against /d/ after /int/-/u/ >>16308739
>>16307798>Hence the MIT workPlease elaborate.
>>16306487Is there an EM field that can be captured with an inductor?
this fuking faggot scientist all u need for plasmuh is microvawe and grapes/matches?
>>16304758that's pretty impressive for a device of that size, although i'm not surprised that they don't have a clear idea of which of their changes actually let them push it to that density - so much of modern fusion engineering is just ad hoc kitchen sink crap where they try stuff until they find something that works and then keep doing that - often making little effort to understand why their change worked.
>>16303705/ssg/ pronto please. Would finally give me motivation to get some textbooks on it.Not much to contribute since am chemist, but wanted to bring up ICP instrumentation for mass spec and atomic emission spec as I couldn't see any references to it already. Very useful technique, I have a coworker who used to do it exclusively and have heard many cool stories from him but have not been near any such instrument so far.If anyone here has any videos of ICP setups please share. Youtube searches get stale results (the good stuff gets washed out by all the mass-produced test-prep tutorial vids) but I know there must be some good stuff out there. https://www.youtube.com/watch?v=mQpkqydA40w was one of the more interesting vids I found. I may be stupid though and just don't know where to look.
>>16310494Never heard of it before - what are the advantages of this over usual optical and mass spectroscopy techniques?I'll see if I can dig up some material in the meantime.
>>16310494Most recent review paper of ICP spectroscopy I've been able to find so far, but it's 20 years old. I'll see what else I can find - this does have some good setup schematics in it.
How do you use non-thermal plasma for eletric generation? How do you ionize it without a electrical field? Can you ionize gas to a non-htermal plasma thermally?
>>16310515The advantages as far as I understand it are that you get far higher temperatures, thus Maxwell-Boltzmann statistics say that you'll see far more atoms in the excited states that you're interested in, thus the emission lines are easier to detect and you have far lower limits of detection (though I may be exaggerating -- I think that the advantages are really quite good but not many facilities want to spend the copious amounts of money on argon needed. A typical setup will burn through like nearly a liter of Ar per second IIRC). For absorption, the improvements aren't that grand -- the main advantage is the very good atomization that comes from the system. It does have the drawback of being susceptible to low-frequency noise from the variation in Argon flow rates.>>16310977Thanks for sharing, looks like some interesting stuff in here. The figures look pretty good -- pretty readable despite getting digitization-butchered. Just wish that they had even one spectrogram, but I guess you can get away with a lot when publishing a review.In any case, I'll keep my eyes out for any other good refs on the subject.
>>16311487so it's a bit like laser-induced fluorescence or neutral gas spectroscopy where you're taking advantage of the velocity distribution of the plasma species to alter or enhance part of your spectrum?in LIF you're exciting metastable states at a scannable frequency to determine the shift in the maxwellianin NGS you're using broadening and shifting of the spectral lines to infer information about the pressure and motionand i guess it sounds like in ICPMS you're taking advantage of the higher temperatures to excite emission lines of trace gasses or faint absorption spectra for colder gasses or nanoparticles?>A typical setup will burn through like nearly a liter of Ar per secondfucking hell - that's a 300 cf tank in two hours, i usually don't go through more than one of those a year.
>>16311098>How do you use non-thermal plasma for electric generation?As far as I know, you don't. LTPs/NTPs are very good at driving chemical reactions, not so good at fusion... although depending on the type of heating processes used in a fusion device you can often end up with different electron and ion temperatures, but it's usually within an order of magnitude as I understand it, whereas in LTPs/NTPs your ions are basically in thermal equilibrium with your room temperature gas (~1/40 eV) compared to electron temperatures of a few eV or tens of eV.>How do you ionize it without a electrical field?There are several paths towards ionization apart from using a strong electric field to drive electrical breakdown. Chemical interactions between certain reagents can drive limited ionization in mixing gasses, high-energy photons can drive photoionization, and elements with low ionization potentials like alkalis can be thermally ionized with a hot filament or plate. I don't know enough chemistry to comment on chemical ionization processes, but photoionization and thermal ionization aren't good for trying to make NTPs, especially not at high pressure. Field ionization is how you're going to make 99% of laboratory plasmas.>Can you ionize gas to a non-thermal plasma thermally?I won't say 'no', but from experience, I'll say 'not likely'. Generating a plasma through thermal ionization, like in a Q-machine, produces a plasma that is very strongly-ionized and with electron and ion temperatures that are very, very close. Now, that's not to say you couldn't try to take a thermally ionized plasma and push it *out* of thermal equilibrium, maybe by introducing more neutral gas, but it'd probably have to be neutrals of a different species (since any gas from the ion species will just thermally ionize with the rest) and that means you're going to have to deal with potential chemical interactions or instabilities driven by mass differences between the ion and neutral species.
>>16311487This one's got some spectra examples, but I could only find a pre-print copy off sci-hub.
>>16307529What am I looking at here?
>>16304758they say the ions are expected to lose confinement at the high electron densities, but it's kind of a throwaway line - is that inherent to their device, or a problem any RFP torus designs will have to deal with? i guess what i'm asking for is the relationship between cyclotron frequency and ion density in an RFP. do we know a general trend, or is it always somewhat device-specific? it's not a common fusion testbed, so i'd understand if it's just an unknown.it'd be a little discouraging if those are directly coupled, as it could make achieving a super-dense electron plasma in an RFP basically useless for actual fusion, since using ion cyclotron resonance heating to heat the plasma would prevent it from being confined.
>>16309374MIT people are working on a compact tokamak based off their research on using novel materials to make superstrong magnets
>>16303423When is ITER getting cancelled and which project is actually more likely to become a viable fusion reactor that can actually be used commercially?
Took anon's advice about taking apart a plasma lighter to use as a voltage source and I'm actually impressed with how well it works. Disassembly is pretty simple, as most of the physical body of these lighters appears to be aesthetic, not functional, and the entire disassembly only took 2-3 minutes. The actual components inside are broken very neatly into (a) the battery and USB-C recharge port, (b) the circuit board which just contains a handful of resistors, capacitors, and ICs, and (c) a little potted transformer - and that's all.Clipped the leads from the transformer to the conductive ends on an old neon discharge tube and it's not too bad - high enough voltage to achieve breakdown across a pretty long tube (~20 cm). Only downside is that it's not particularly stable (I've not been able to get the plasma to remain ignited for more than a second or two). Not sure if this is a plasma stability issue or if the circuit is overloading (or if it just has a built-in limiter). There also seem to be some insulation issues, and the you'll get some arcing across the base of the transformer leads if the tubing slips at all or if the ends aren't close enough to arc through the air or through the tube.Worth experimenting with as a poor-man's HV supply for little demos and things. Might do some tinkering this weekend - if I manage to reverse engineer what all of the ICs and component values are, I'll post the circuit diagram.
>>16314402for better or worse we're stuck with it now. too many countries have invested too much money to just cancel it.
>>16315212>Not sure if this is a plasma stability issue or if the circuit is overloading (or if it just has a built-in limiter)probably a built-in limiter. might even just be a short timer in one of the ICs. i'd imagine there's some kind of limiter to prevent the lighter from discharging continuously.
>>16315227That's a fallacy, it should be cancelled immediately and funds redirected to better efforts
>>16303423have a pic
>>16314402It isn't, given that it isn't meant to be a commercial reactor.
>>16314387If I'm reading it correctly (big if) it sounds like the problem is that as electron density increases, so does ion density, but as ion density increases your ion-ion collision rate becomes comparable to your gyrofrequency, or, in other words, the average circumference of the circle your ions travel along due to gyromotion becomes smaller than the average distance between ion Coulomb collisions and your ion motion becomes less dominated by gyromotion and more dominated by diffusion.Your collision frequency in a quasi-neutral plasma scales about linearly with density, as I recall, so as density goes up, collision frequency goes up, and as collision frequency goes up, collisions cause more diffusion perpendicular to the magnetic field lines.As far as workarounds to this, I suppose you could either choose an ion species that minimizes that collision cross-section as much as possible (how do you ion-ion collision cross sections for ionized Hydrogen and Helium isotopes compare?) or maybe choose a magnetic field gradient that minimizes collisional diffusion?
>>16316005Fallacy or not, it's what's going to happen and what the justification for it happening will be. Governments don't know what the 'sunk cost fallacy' is.
What should I look for to study just regular fire?I assume there's research on the subject.Maybe it's not quite as exciting as other forms of plasma, but I'm curious.What's the go-to literature for regular 'ol flames?
>>16318131“Combustion Physics” by Michael Liberman is the most comprehensive and up to date reference on the relevant physics. There’s much more hydrodynamics than plasma physics in the study of flames since the ionization fraction is only 1/10^10 at typical temperatures so plasma effects generally don’t dominate the behavior. The exceptions are electronic control of diffusion flames where propagation is controlled by an externally applied electric field i.e. https://apps.dtic.mil/sti/tr/pdf/ADA473196.pdf and Lawton and Weinberg’s book, or in astrophysical/ICF where the propagation of ionization fronts are important for the combustion behavior.
OP should include the NRL plasma formulary in future threads
>>16318447>There’s much more hydrodynamics than plasma physics in the study of flames since the ionization fraction is only 1/10^10 at typical temperatures so plasma effects generally don’t dominate the behavior.Yeesh, that's putting it mildly. I did some quick back of the envelop calculations, and for an atmospheric pressure gas with a low electron temperature, then your Debye length over your neutral gas mean free path is somewhere in the thousands. It's hard to imagine any circumstances where electrical effects would ever enter into the equation, though I'll take your word about there being a handful of exceptions.
>>16320093>It's hard to imagine any circumstances where electrical effects would ever enter into the equationA candle flame is easily deflected by a Van de Graaff generator, and the same candle flame can readily increase the spark-gap distance for an electric arc in air.In short, there is "enough" plasma in there to have some significant effects.But yes, people who say "fire=plasma" are oversimplifying pretty severely.The sky is not all "gas" (as shown by the presence of clouds) and fire is not all "plasma."
>>16320204>A candle flame is easily deflected by a Van de Graaff generator, and the same candle flame can readily increase the spark-gap distance for an electric arc in air.
>>16307529 >>16303871Some very interesting work on Plasma was conducted by some dude who posted to youtube and then disappeared. He used bowl-shaped magnets to direct plasma in a vac tube and was able to contain it between two of these bowls for a continuous timeframe.You can find the series listed under the Primer Fields on yt. He shows the whole setup as well as how the bowls were created, and tons of other info.
Interesting publication I thought I'd post here. Every five years the IOP publishes the 'Plasma Roadmap', an extended review of current breakthroughs and topics of future interest in low-temperature plasmas - basically a snapshot of where LTP topics are and where they seem to be going.The 2022 Roadmap includes reviews of plasma excitation and generation, extreme plasma regimes, plasma and liquid interactions, dusty plasmas, plasma processing and manufacturing, plasma medicine, plasma propulsion, plasma diagnostics, etc.>https://iopscience.iop.org/article/10.1088/1361-6463/ac5e1c/pdfDefinitely worth a read for anyone interested in learning more about plasma topics outside of fusion.
>>16320921i've always thought those things were cool as hell, and didn't get nearly enough attention because, like basically anything even tangentially related to "electric universe" stuff, it's really cool ideas (that have some cogent explanations for outstanding problems in cosmology especially), except presented alongside a bunch of weird pseudohistorical bullshit. and often a staggeringly poor understanding of, of all things, geology.and of course you've got your "the gubmint is surpressin' the tech" schizos along for just about any ride they can find.at least there's plasma cosmology, which is a bit less associated with the nonsense, but keeps some of the better ideas.>>16320093>>16320204a flame might be better considered as a dusty plasma. i believe the Debye length can be reduced in dusty plasmas, albeit not, AFAICT, by all that much in a flame - here's a relevant paper (it's not talking about flames, just some equation modeling work) https://doi.org/10.1007/BF00627441 for many of the flames generally encountered in daily life, they're full of a bunch of agglomerations of mostly carbon atoms, which could act as dust grains.seems like something super trivial to test, too - characterizing electromagnetic phenomena (or lack thereof) for something like a hydrogen/oxygen flame, a methane/oxygen flame, an aromatic hydrocarbon/oxygen flame (since IIRC you get more carbon grain formation in the flame with an aromatic fuel), etc., just to see how much of the effect is just "a whole bunch of heated aromatic carbon floating around"surely somebody's done that at some point.
>>16319042>cgsfucking why
>>16322204Dusty plasmas usually invoke what they call an 'aggregate' Debye length, calculated as the geometric mean of the ion and electron Debye lengths.[math]\frac{1}{\lambda_D}=\frac{1}{\lambda_{de}}+\frac{1}{\lambda_{di}}[/math]As I recall, it's because the gradient length scale for your sheath around the particles scales like that geometric mean.Since Debye length is controlled by species density and temperature, for a quasineutral plasma with a cold ion species, this usually ends up being approximately equal to the ion Debye length for more low-temperature or atmospheric pressure plasmas.
>>16322409Shot in the dark, but - I'm going to guess most of the people who would need a 'plasma physics formulary' are experimentalists, and most of them would be measuring smaller experiments, diagnostics, etc. in centimeters and grams rather than meters and kilograms.
>>16322204There've been several dusty plasma experiments specifically looking at in-situ formation of carbon agglomerates in chemically-reactive plasmas.As I recall, they introduce chemicals like acetylene or methane into argon or nitrogen plasmas in different concentrations to look at the rate at which particles grow, making little clouds of dust spontaneously form in the plasma. Since the equilibrium conditions of the dust depend on the particle size and the plasma conditions, you usually reach a critical size where the dust cloud can't remain stable within the plasma anymore and I think it either expands out of its confining potential or falls out of the levitating electric field or something and then new particles start growing in the plasma again.My understanding is that dealing with agglomerate particles is a fucking nightmare in terms of trying to analyze your data. Dealing with non-spherical dust (ex. borides, silicates, etc.) is already bad enough, but you can at least approximate those kinds of particles with regular shapes; but with twiddly little chains or strands of particles, you can't really even approach modelling them analytically, so researchers have to rely heavily on simulations to try and get any sense of what the particles may or may not be doing.
>>16323333fucking nanolobsters contaminating my plasmas
i am still working on a solid state plasma drive for humanity ... imagine a future where being injured and dying was illegalthe unity!
>>16323951meds, take them
>>16322204I haven't been able to find anything looking at treating fire particulates as dusty plasmas, but I did find a neat article where they looked at the effects of an electric field on the speed of flames.
>>16314398Is SPARC actually being designed and constructed now? I thought it was still in the "drawing on a diner napkin" phase of development.
>>16303702Calls out trannies, posts tranime image>shieeeet
>>16325599hownew.ru
>>16323333There was actually a paper in Nature earlier this year that looked at how molecules form into nanoparticle aggregates. Pretty good read.
>>16325670I read some nano articles in 2013-2014 range. I have a single question because I remember specifically reading that gross chemical properties of atoms, that is when there are many of them, are different from when there are fewer. And that as the numbers grow fewer still, their properties continue to change. Is this true?
>>16325764>gross chemical properties of atoms, that is when there are many of them, are different from when there are fewer. And that as the numbers grow fewer still, their properties continue to changeNot quite sure I follow you.
>>16326255I think he’s referring to how the band structure is different for small clusters of atoms than for infinitely large bulk materials, and the lower density of states ends up changing the chemical and optical properties, including occasionally the stable crystal structure. Quantum mechanical behavior becomes dominant in nano materials when the particles are on the order of the de Broglie wavelength of the electrons which is around 10 nm at room temperature.
>>16306307ignorant tourist herewould this help?https://www.youtube.com/watch?v=zcpDGKH9_SE
>>16326944i was under the impression that optical properties change at much, much larger scales than that (generally around the wavelength of the light frequency in question - at 10nm you're hitting everything with soft x-rays - although some really weird stuff happens to the thermal emission of dust particles that are smaller than what should be the peak wavelength of their blackbody spectrum)for changes in chemical properties, there's also just the mundane "catalytic" effect from a) a hugely increased surface area to react with and b) much less energy lost to disrupting a lattice.
hi nerds, I might be working with ITER later this year on software stuff. what am I in for?>>16320093>>16320204these kinds of effects formed the basis of early electronic amplifiers/oscillators like the arc converter
>>16327245Pretty solid video with some good tips. A few asides:>If you don't need to get to super low baseline pressures you can get away with acrylic/plastic tubing instead of borosilicate. You will have to deal with significant outgassing, but - again - not a huge issue if you just want something to glow. For something that you can get to lower pressures and less outgassing, though, BS is definitely superior. Be wary of getting vessels that aren't going to be good at holding up against a vacuum though, and be careful of any signs of damage or wear as implosions can be extremely dangerous (this is why new Bell jars are required to be sold with a cage now)>Most stores like Lowes or Home Depot sell fluorescent light ballasts, which can be connected to a variac or run off of a switch to mains, and which will both have a high enough voltage to achieve breakdown across a large volume, as well as automatically switch to a current-limited mode, for about $20-30.>If you want a good glow instead of arcing, machine together some larger electrodes instead of just using pipes or wires - having a set of large flat surfaces instead of narrow points will let you generate a more homogeneous, 'softer' glow discharge.>Avoid using teflon tape or similar products to seal connections - while it is good at helping block leaks, it has a tendency to tear and split over time, and if those little scraps get sucked into your vacuum pump they can completely fuck it up. Just buy a tube of vacuum grease and some nitrile gloves off Amazon or wherever for like $50 and grease up any threads going into the chamber. One tube will last you for years.>A good gas and vacuum line should include two needle/isolation valves (one to control gas inflow from a tank or the atmosphere, and one to control gas outflow to the vacuum pump) and it's also good practice to include a leak valve somewhere in the line so that you can repressurize without having to disassemble parts of the chamber.
>>16328644Are you collaborating remotely or actually going there?
>>16323951show us your work so far
>>16329438remotely, at least for now
>>16329270>vacuum grease>$50jesus dude, you're getting fleeced
>>16329534UHV stuff is expensivetry getting some UHV epoxy
>>16329537you know what your university and industry pays isn't what things actually cost, right? small markets are highly susceptible to grift
>>16329582no one pays what things actually cost anon. paying more for things than they're worth is where profit comes from
>>16329617nta but you are being pedantic for no reason.you could have asked that anon for an actual source instead
>>16329633pedantic? on /sci/? I never!
>>16329534A 150 gram tube of high vacuum grease from Dow Corning or DuPont or whatever they're called now runs about $35-40. That plus $5-10 for a pack of gloves so you haven't got grease on your hands for the next week adds up to $40-50. You can go for a smaller, cheaper tube but if you've got a small setup the 150 gram tube can last for years, so it's a reasonable investment.>>16329537A low vapor epoxy resin like TorrSeal will usually run about $100 for about a 100 grams total of mixer and hardener (I think the mix ratio is like 2-to-1 or something). If you can get away with something a bit shittier, Loctite has a reasonably good epoxy for glass-glass, glass-metal, and acrylic-metal seals that I've used for making viewports and things, I think it runs about $35-40 a tube - just don't expect great baseline pressures.>>16329582You can get parts and chemicals and electronics and things cheaper if you go through surplus or auctions or whatever, but (a) it can be hard to find what you're looking for, (b) you're having to compete with everyone else looking for that stuff, and a lot of your competitors will have deeper pockets than you do, and (c) unless you've got a reliable connection, quality can be very hit or miss.
>>16329678I think loctite has a compound called 1620 or something that we used in a project. was difficult to get a hold of but surprisingly cheap
>>16330018Loctite 1C and 592 are both good for moderate vacuum pressures, but I'd say you probably want something more like a TS or Vacseal compound if you want to seal a UHV system. Epoxy resins are good for anything that just needs to be "good enough", I use them for sealing classroom demos and things like that. Most of them cure in a couple of days and they're easy to machine as well, so if you're a little sloppy with the application you can clean it up with some sandpaper or a dremel after it cures. Honestly, though, if you're making a permanent seal, and if you've got the skills, the equipment, and the time, just fucking weld that shit - nothing trumps a good weld.If anon is building something they want to be easier to take apart or modify, go with some aluminum or stainless kwik-flange or conflat flange parts - the former are sealed using fluorocarbon o-rings (reusable) and the latter with copper gaskets (not-reusable, but an excellent metal-on-metal seal).
>>16328644Expect to be in a ‘small fish/big pond’ situation. You’re going to be one of hundreds of students and full-time people working on projects.
>>16328224>i was under the impression that optical properties change at much, much larger scales than that (generally around the wavelength of the light frequency in questionAs your particle size increases you transition between different behavioral regimes for light scattering. Rayleigh dominates in the [math]D \ll \lambda[/math] regime, and Mie in the [math]D \sim \lambda[/math] regime, and eventually as [math]D \gg \lambda[/math] you asymptote to an Optical regime - the scattering intensity transitions from being isotropic in the Rayleigh limit, to increasingly anisotropic in the Mie and Optical limits. It's what leads to different scattering effects in the atmosphere (Rayleigh leads to a lot of the small wavelength shifts we see that changes the color of the sky as the viewing angle of the Sun changes, while Mie leads to a lot of the halo effects around the Sun and Moon).>some really weird stuff happens to the thermal emission of dust particles that are smaller than what should be the peak wavelength of their blackbody spectrumThat wouldn't surprise me. From what I understand, surface properties of dust particles, especially in a plasma environment, are mostly an unknown. There are models of a lot of surface behavior, surface charging, surface ablation, etc. but they're actually really hard to confirm because (a) so much of what's happening can be altered by the presence of the plasma and (b) any instruments you could use to measure these things inherently disrupt the system. It's the same reason they're pushing so hard to develop new optical diagnostics for plasmas; you can't stick a Langmuir probe into a dusty plasma without pushing all the dust away, you can't really get reliable LIF data because of how the dust affects the ion population and plasma structure, you can't get great results off of impedance probes because you don't know how uniform the charging behavior is, etc.
>>16327245How dangerous are the electronics for this kind of setup? I know a lot of plasma stuff is inherently high voltage and that kind of scares the crap out of me. But I also kind of want to tinker around with this kind of stuff.
>>16332709>How dangerous are the electronics for this kind of setup?I have no cluebut have a bump
>>16303424>Useful Resources (WIP):Web pages are being rescued from a Wiki that is being killed, and transferred to the Installgentoo WIki. In that connection, your reasing list was uploaded:https://wiki.installgentoo.com/wiki//ppg/_Resource_List
why not just pew pew protons at boron-11? I presume they thermalize, but what if they have lots of energy like 100 MeV?
>>16334496the franks are betting on that, yes.
>>16334496>>16334560i believe there's a massive unsolved problem where the proton beam loses a lot of energy to scattering in the boron lattice.
>>16334496You obviously can do that, commerical neutron sources use D-D or D-T beam target fusion.There's no point in using 100 MeV to get a reaction which produces 9 MeV, espeically since the scattering cross section is several orders of magntudie larger than the fusion cross section
>>16334702yeah that's the gist I got - scattering causes the protons to both lose energy and to thermalize>>16335152and I guess ~1 MeV isn't enough to get a useful amount of reactions?
>>16332709>>16333862If you're being smart and cautious it's no more dangerous than any other electrical system, there's just a few extra things to be mindful of - most importantly that dealing with high voltage means being cautious of the fact that insulation will be less effective and current can potentially arc across small air gaps or through thinner gloves, etc. It's generally a good idea to use only use as high a voltage as is necessary to achieve a breakdown (usually 1-2 kV is plenty to achieve breakdown for most gasses at a few tens or hundreds of mTorr and a gap of a couple centimeters) and use a crossover circuit/current limiter to drop it down to a current controlled mode the instant it hits breakdown (the plasma can usually be sustained at just a couple hundred volts once it's lit).A lot of risks can be avoided by just using common sense: Don't force excessive currents through a chamber - most glow discharges can be sustained on a milliamp or even less, so don't go making a hundred milliamp plasma. Use insulated feedthroughs to get electricity to your electrodes and ground the shit out of your chamber so you minimize risk of accidental discharging. And if something feels stupid or dangerous don't do it because it probably is - the vast majority of people you hear about electrocuting themselves working with DIY high voltage stuff are doing retarded shit like messing about with microwave oven transformers or taking a 15+ kV transformer from a building sign, soldering a plug on, and running it to the fucking mains. Don't work on anything while it's live. Use the one hand rule. Yadda yadda yadda.
>>16303423oh shit, I forgot about this thread while discussing about this article that someone posted in /sfg/ the other day:https://caseyhandmer.wordpress.com/2024/08/18/antimatter-is-the-best-post-chemical-rocket-propulsion-system/this guy suggest transforming excess solar energy into antimatter for space travel, and maybe even energy storage (if scientists are able to find ways to make antimatter MUCH more efficient than today...)AFAIU, the proposed idea for space travel is something like this:https://projectrho.com/public_html/rocket/enginelist3.php#id--Antimatter--Solid_Corehere's his twitter post, in case anyone careshttps://x.com/CJHandmer/status/1825081201192804668
>>16303423>>16303424>>16303426What are you guys doing? This looks illegal
>>16335594>What are you guys doing? This looks illegal
bump for >>16335584the catalog is full of schizo crap
>>16332709It’s fairly safe if you don’t do anything stupid like have an exposed contact touching a metal table and you use cables that are actually rated to handle the voltage.1-2 kV is enough to break down the outer layer of your skin, which provides most of the resistance in the human body, so you should definitely get a power supply which is limited to 10s of mA to be safe, or at least put a large resistor in series with the tube to limit the current output.Any sort of contact has some capacitance which can hold charge, so you should have a resistor of a few megaohms between anything charged to high voltage and ground. To be extra safe, you can touch all exposed metal contacts with a shorting stick connected to ground before handling them, but it probably isn’t necessary at these voltages since there isn’t enough stored charge in anything to kill you.Make sure to use multiple diodes in series in case one of them fails in the rectifying circuit.
>>16332709a friend of mine got a 15 kV kiss about a decade ago. apparently it was not fun. take appropriate precautions like what >>16336536 and also wear insulating gloves and follow the one hand rule - only ever touch the HV stuff with one hand, put the other hand behind your back
>>16335584>caseyhandmerWasn't this one of the guys who fell for the hypermeme?
>>16336566>wear insulating glovesAre gloves even any good against 15kV? They just sound like a false sense of security at that point
>>16336656depends on the thickness
>>16336656The breakdown field in most rubbers is greater than 10 kV/mm DC, it doesn't take a thick glove. I personally don't wear them and it's still better to never touch anything live, but it can't hurt to wear them.>>16332709Since nobody's mentioned it yet, the main cause of fatal electrocution is current flowing through the heart and causing ventricular fibrilation, that's the reason for working with one hand to prevent the current from flowing into one arm and to ground out the other. Actually, the current path from arm to leg is more dangerous than arm to arm, so with much higher voltages it's good to stand on an insulating material instead of metal or concrete floors.
>>16336725this. air by comparison is what 2-3 MV/m breakdown? and there are materials that withstand way more than that. PTFE comes to mind. maybe FKM (viton) too
>>16332709Following up on what >>16336536 said - if at all possible just ground *everything*>What do you mean everything?E V E R Y T H I N G !Having all of your supplies, instruments, and even the walls and supporting extrusions of plasma chamber sharing a common connection to a dedicated ground terminal or just the grounded exterior of a breaker box significantly reduces the risk of an accidental shock. Anything that *can* be grounded without compromising the function of the circuit should be.>>16336729Air is about 2-3 MV/mAlumina ceramic has a breakdown rating of, I wanna say something like 10-15Viton is like 15-20Borosilicate is like 20-30PTFE is something crazy like a hundred I think
>>16336846>PTFE is something crazy like a hundred I thinkWP says 19-173 MV/m dependinghttps://en.wikipedia.org/wiki/Dielectric_strength
>>16306487>plasma tapsThose are the things in the bridge consoles that explode when the ship gets hit
>>16336634dunno but he seems like the type, yeah
>>16303423that looks cool
>>16306487>>16309555As I recall, the internal magnetic field of the plasma in fusion systems is strong enough that you can induce an electric current in the chamber wall,But I imagine that’s pretty small compared to what you need to power it.Most of your power is gonna be in the form of heat generated from particle radiation and then goes to the standard heat-to-water-to-steam-to-turbine route.
Bump
>>16336725>10 kV/mm DCYeah that's not a comfortable margin at all
>>16338772eu fags can fuck right off back to >>>/x/ where they belong
>>16337117This seems like poor console design.
>>16338714No, it’s really not. It’s not good to trust the gloves unless you have a setup to test for punctures and tears which would be susceptible to surface flashover. Solid dielectric also degrade over time at high voltages because electromechanical forces promote void formation in the bulk material which can then coalesce and eventually breakdown by capacitive coupling to the externally applied voltage. I’ve seen inch thick polypropylene get punched through by 85 kV from continually applied stresses even though it should take 650 kV according to the nominal breakdown strength.
>>16339377Never trust nominal ratings
Anyone here work in the fusion industry? I recently left due to becoming very disillusioned with the work being done there. Curious to hear if others have found more meaningful or interesting plasma physics in private fusion.
>>16341133>I recently left due to becoming very disillusioned with the work being done there.What was the problem?
>>16341171There is a belief, and I think it is an almost faith-based belief, that technological advances will ensure that suddenly we can keep plasmas stable that weren’t historically. I guess I am saying that people seem to think you can engineer around a fundamental physics problem.Still there are amazing people in the industry and good work being done, a lot of it does feel wasteful though. Private companies have to strategize on how to raise more funds, and often what raises more money may be rather useless with respect to progress towards sustained fusion reactions.
>>16341336>I guess I am saying that people seem to think you can engineer around a fundamental physics problem.Well, we have definitely done that in the past.
>>16341133What are you going to do now? What's your degree?Do other people feel like you in the field?
>>16341425I am not saying you cannot engineer a solution to a problem I am saying you cannot to a fundamental physics problem.An example is a perpetual motion machine, it is fundamentally an impossible problem.If fusion were easy the only sources of it in the universe would not be some of its more massive celestial bodies.
>>16341437I am an MSc, withdrew from my Phd during the pandemic, no intention to complete it. I have some experience in quantum photonics and have moved to an applications role there. I am at heart a sceptic if you cannot tell, so to be truthful the new quantum computing industry is imo also full of the same problems as private fusion. That said, photonics have near term real applications and benefits in the semi conductor industry. It feels better for me at least to work on something that I know and can see will have real impact technologically.
>>16341927a lot of science is doing things with a 99% failure rate, maybe higher. thats what separates it from engineering; if youre an engineer, youre expected to make things that actually work. scientists will fail over and over again before they make any material progress, but thats what inevitably needs to be done before real progress is made. everyone has a part to play, dont get discouraged by it.
>>16341894>If fusion were easy the only sources of it in the universe would not be some of its more massive celestial bodies.So you're saying that there's a chance.
what is the point of plasma other than building fancy glowing lights. you can make this shit in the microwave with a grape
>>16341955Precisely, and fusion is still science. Building a fusion reactor is not as clear cut as just engineering good plasma confinement, there is a massive amount of physics that is poorly understood in plasmas.
>>16342015Nuclear fusion for propulsion and power. Also it is rich in a lot of interesting physics.
>>16342015ignoring all the fusion stuff, the biggest application of plasmas is using them as an intermediary or facilitator for the treatment of materials and surfaces - surface cleaning, etching, deposition, and activation all require plasmas. the fabrication of micro/nanoelectronics would be impossible without plasmas; every single digital device on the market today has one or more components that require multiple steps of plasma processing to manufacture them.
>>16342015im not a plamsa physicist, but i do make novel semiconductor devices, and one of the things we do in processing is subject the wafer to a thin bed of plasma, which eats away at the wafer, depending on what the wafer is made of and what the plasma is made of. you can use it to etch away the material at a relatively controlled and predictable rate (plasma etching), or you can make oxygen plasma which is very aggressive towards organic materials, like photoresist, while leaving the semiconductor relatively untouched (plasma ashing, much more common).>>16342040this>>16342033well if nothing else you can convince governments to give you money for plasma research a lot more easily if you tell them it might result in a net-positive fusion reactor (and who knows, it might).
>>16342015Just off the top of my head:Treating plastics/polymers, including making plastic inkable, Saran wrap stick, making artificial skin biocompatibleHardening metals vis ion implantation, a lot of tools wouldn’t exist without itDepositing infrared reflective coatings on glass, which is necessary for skyscrapers, also anti-glare coatings on screens for electronicsPlasma assisted chemical vapor deposition, including artificial diamondsMetallizing ceramicsRemoving contaminants from water and air, also disinfecting medical equipmentTreating seeds so they are more permeable to waterCreating ammonium nitrate fertilizer in situ from just air and waterPlasma displays and lightingElectric propulsionHigh power UV lasersControlling air flow around the wings of fighter jets at high angle of attackAnd generating the microwaves you used for the grape
>>16336846>>16336849what's the dielectric strength of CCTO? i know it has a fucking bonkers permittivity of like 10,000.that, IIRC, according to theories modeling permittivity should be around... 49.
I don't know much about this plasma stuff but it sounds a lot like aerodynamicsDo you ever encounter the golf ball effect in any way? Where intentionally created turbulence leads to increased plasma stability?
>>16342147you have to be able to control the location of the turbulence and said turbulence has to have a predictable net effect on the fluid. plasma instabilities conveniently satisfy... neither of those.plasma is compressible fluid dynamics plus charge dynamics plus magnetic field dynamics plus multiple meaningfully different particle species interacting (the minimum is 2, even in a "single species plasma," because electrons and ions behave differently). it's nightmarishly unpredictable - basically the only way to control it reliably is brute force, and we've been struggling to even do that for nearly 80 years at this point.
>>16342106>Creating ammonium nitrate fertilizer in situ from just air and waterActually it bypasses the ammonia/Haber process entirely in favor of the Birkeland process - the ionization of nitrogen and oxygen in the air produces different nitrate molecules, which catalyze with water to form hydronium and nitrate:[math]N_2 + O_2 \rightarrow 2 NO[/math][math]2 NO + O_2 \rightarrow 2 NO_2[/math][math]3 N O_2 + H_2 O \rightarrow 2 H N O_3 + N O[/math][math]H N O_3 + H_2 O \rightarrow {H_3 O}^{+} + {N O_3}^{-}[/math]The process was developed by Birkeland a century ago, but was abandoned in favor of the Haber process because, at the time, we didn't have any energy or cost-effective ways of generating atmospheric pressure plasmas.This is the one I'm most excited for (yes, I know that sounds lame, but hear me out): Several research groups have done preliminary proof-of-concept tests over the last 10-15 years and this technology will, nominally, start seeing practical production within the next decade. Replacing ammonia-based fertilizers is a game-changer for agriculture: It's substantially cheaper, significantly better for the long-term health of arable land, and unimaginably safer. In addition, there's evidence that pre-treatment of seeds and seedlings with CAP jets can reduce germination time, stimulate faster root growth, and lead to yields 15-25% higher than traditional ag chemicals.Plasma technology will make farming more affordable and profitable as a career, while driving actual food prices lower and increasing availability. Plasmas will unironically solve world hunger.
bump
>>16343588with my brains and your brains we'll make an excellent team
>>16342147I'm not familiar with any applications where intentionally created turbulence leads to increased stability, but there are a lot of cases where intentionally created asymmetries lead to increased stabilities.Dusty plasmas like >>16322048 are a good example. You would think that to get a good, stable cloud of dust in your experiment, you'd want everything nice and aligned and symmetric and shit, but actually it's the asymmetries that make it easier to get a good, stable structure - moving your electrodes so that they're slightly misaligned or inclined or not quite the same shape, etc.
>>16342106>Electric propulsionmeme application - electric propulsion is never going to be effective enough to apply on practical probes and transports.
>>16303423>>16303423Can you really touch the plasma safely in some of these machine like music box electricity arc? And if so, can you touch the arc lighter? Answer appreciated
Can anyone else see a red glow, not the plasma? I'm here from the red glow last time.
>>16345208>electric propulsion is never going to be effective enough to apply on practical probes
>>16345442>will take six years to get into a orbital trajectory 2 AU away, even with an optimal launch window>will take months after intercept to transition into a stable orbit>practical
>>16345658perfectly practical, especially if you have several missions going on at the same time. even getting to Mars by conventional means takes years, on average 1 year waiting for a window and then between ½-1 year for the actual transfer
>>16345208Electric propulsion is already in use, what are you on about?
>>16345208Idgaf about deep space travel, it’s useful for station keeping and saves mass/money for orbit raising
>>16342147Not really, but plasma is actually used to prevent flow separation from surfaces to reduce drag.https://files.catbox.moe/bcojpv.pdf
>>16342343>make farming more affordable and profitable as a career, while driving actual food prices lowerBad news about that. Farmers' financial well-being depends on higher prices for crops.Hunger is also a matter of income and 3/4 of people who go hungry live in rural areas. They're too poor because crop prices are too low.But good to hear about this.
>>16345821that just means agricultural capital would become more concentrated, which is historically progressivetotal death to muh small farmers
>>16345837>agricultural capital would become more concentrated, which is historically progressivedefine progress
>>16345821>increase yield by 25%>decrease price by 20%>you move more stuff because it costs less and make more profit
>>16345846transitioning out of the remnants of feudal society, fully into capitalism. the dispossession of the peasantry, fully completed in Europe, has yet to happen worldwide
>>16345271For a glow discharge plasma? No, because those are formed inside a vacuum chamber at low pressure.For a tesla coil or a plasma lighter? No, because in both cases, you complete the conductive path for that arc. Painful, certainly. Fatal if it's a high enough voltage/current combination.However, in CAP/NTP jets (cold atmospheric plasmas, sometimes called non-thermal plasmas), most of the actual plasma is formed inside a longer tube or apparatus and it's only a little bit of the diffuse plasma that's carried out with the flowing neutral gas before recombining that actually makes contact with your skin. It's still smaller, so it can still carry a discharge current along to the point of contact, but the addition of the neutral gas significantly mediates the effect.The arc from a tesla coil in the air will have an ionization ratio of a few percent.The arc from a CAP/NTP jet will have an ionization ratio of maybe a few thousandths or millionths of a percent.It tingles like a mild electric shock, and can cause small involuntary contractions in the muscle tissue, but it's not significantly painful or fatal (as long as you've built it right!). It can still cause minor damage to the skin with prolonged exposure (see link below), which is believed to be a combination of minor thermal burns from direct electric shock and responses to reactive oxygen and nitrogen in the jet. However these are both a minor effect and the total damage is relatively easy to mediate. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5381889/They're pretty neat though!
>>16345858>the dispossession of the peasantry, fully completed in EuropeEurope subsidizes its small farmers like one else.>>16345847Very convenient to predict that price descrease will be proportionally smaller than yield increase.In any case, it would make no difference for the starving Mozambican farmer whether the United Stated wastes 42% of its food production instead of just 30%, like it is now, because he's too poor to buy anything anyway. The issue with the rural population that goes hungry is that they can't compete with proper civilized people's agriculture.Teaching Afreakan farmers how to properly use fertilizers and irrigation and giving them some respite against competition from Brazil, U.S., Argentina, etc would go much farther than your white man's burden fantasy.
>>16346019>For a tesla coil or a plasma lighter? No, because in both cases, you complete the conductive path for that arc.>le Kirchoff's lawTesla coils are AC devices, not DC ones. Kirchoff doesn't apply to AC. more specifically, the skin effect comes into play. as long as the frequency is high enough you can touch it just fine>>16346075>Europe subsidizes its small farmers like one else.sadly
>>16346205>the skin effect comes into play. as long as the frequency is high enough you can touch it just fineAt the kinds of frequencies most tesla coils operate at, the skin effect really only comes into play for good conductors like metals. For poor conductors (like human tissue), your skin depth scales like:[math]\delta \sim \rho \sqrt{\frac{\epsilon}{\mu}}[/math].And if you do some back of the envelop calculations for typical values of resistivity of human tissues, relative permittivity and permeability, you get that the skin depth of human tissue at tesla/RF frequencies is around 10-100 cm.I've been zapped by tesla coils, transformers, discharges from RF supplies - AC shit can abso-fucking-lutely conduct through you and will if you fuck around or fuck up.
>>16346531>the skin effect really only comes into play for good conductors like metalsoh yeah good point
>>16346019That gif is freaking me out.
>>16346075>Very convenient to predict that price descrease will be proportionally smaller than yield increase.in anon's defense, that is what normal businesses do when they decrease their production costs - decrease sale cost slightly so that you can increase overall sales and customer satisfaction while still experiencing a significant increase in net profit.i mean, it's not what jews do, but it's what normal people do.
>>16342343world hunger is currently a distribution problem. it's just not profitable enough to sell food to starving Africans no matter how much you've made - they've not really got anything to offer in exchange. genuinely more profitable to just let it rot.
>>16348412If only we could arrange a system where Africans agreed to commit members of their community to some kind of overseas unpaid agricultural works program in exchange for trade goods.
>>16348440>wanting more third world immigrationAnd to think that self-anointed chuds were different than liberals
>>16348449
>>16348451I would have taken it as a joke if I hadn't already seen people argue it seriously before. But I digress, this is getting off topic.
Disregard politicsAcquire sheaths
>>16348348I said that because price-elasticity of supply for agricultural goods is such that prices generally fall lower than the proportion of the increase in supply. that's why you see farmers dumping milk on the road and chimping out when there's overproduction of milk, for instance.
>>16348636by "fall lower", I mean that proportion price decreases are higher than the proportion of supply increments.
>>16348412>world hunger is currently a distribution problem...western commies are some of the most stupid people alive, I swear to god. do you want to fuck starving african farmers even harder by throwing American refuse there for free?facts backed by (((FAO)))>starving populations are overwhelmingly rural in shithole countries. places like tanzania, mozambique, malawi, burundi and ethiopia are still overwhelmingly rural.>these starving fellas starve because: they need to plant food, harvest, save for subsistence, for the next seeding, and sell the rest to account for other food staples, agricultural implements and depreciation of tools and they can't do all that with their crops.>falling prices owing to competition from developing and developed countries and absence of industry for cheap manufactured agricultural implements and tools mean that they can't get good enough prices to account for agricultural implements and tools.>they in turn can barely save seeds for the next seeding and sometimes have to sell more seeds to account for emergencies. extreme food insecurity is the norm.>when some (even mild) weather problem comes, such as drought or floods, they lose everything and starve.Agriculture in these places is incomparably less efficient than in other countries. Their lots are also much smaller than anywhere bar southeast asia (where rice is much more productive). It doesn't help that these governments have been despoliating their rural populations since they learned that the urban african populations are the ones who topple governments. they keep prices down to appease the urban wretched of the earth.The solution is to close african markets (more money per harvest), enable agricultural funding and crop insurance, create stable land tenure systems and create (really basic) policies to foster productivity. Wanna help? open a bank that banks tanzanian farmers, don't send your cheap shit there.
>>16348885> CockshottIdiot socialist who can't into calculation problem> Just use bigger computers, broThe same retarded ideology active in AI at this moment.
>>16348940>Idiot socialist who can't into calculation problemmuh ECP is idealist drivel from a pre-scientific understanding of information theory
>>16348636>>16348639>>16348657>>16348885>>16348940>>16348980>economics
>>16349163>you have no controlled experiments>you have no deterministic models>you have no predictive capability>putting friedman as picrellolthe bit about the "Nobel prize" in economics is true though. look it up
>>16349186What am I supposed to say? The situation of life is something like a parrellatom(but a big word like that). I've known it for ages, I'm about 200 90.Yes I do have stuff for you
>>16349209And it's important
>>16349186At the back of my neck going down my hair.
Neat computational paper I found from last month - study of dust/ion wake interactions.Ions in weakly ionized plasmas generally flow in a stream along the field lines of the background electric field as the motion of the ions is mobility-limited by the collisions with neutral gas molecules. When they encounter bodies in the plasma like probe tips or dust particles the flow passed the obstacle creates a 'wake' of ions like a modified sheath structure.Apparently, since the wakes aren't symmetric, it causes weird structures to form and non-reciprocal collisions. Makes them sound almost like a non-Newtonian fluid.
>>16349488does plasma qualify as a fluid in the liquid-gas sense?
>>16348885>if you want to help African farmers then give them tractors factories and Haber–Bosch plantsyou paying?
>>16348885>neoclassical gobbledygookno wonder you guys managed to fuck up every nation you got your hands on.thank god Deng saved china
>>16349578Plasmas are definitely fluids - you need to be at a high enough density and level of interaction to have collective behavior to be considered a plasma - but they're distinct in that they're a 2+ species fluid. You've got (at a minimum) two interacting species (electrons and ions) with different physical properties, that alter the types of fluid behaviors you see.If you start to consider how they interact with the neutral gasses, the possibility of multiple ionization levels or multiple ionized elements, or different temperatures of populations within the plasma, then it gets even more complex.
>>16348657>muh commiehey man, i didn't say we needed to feed starving Africans. i just said why we don't despite having sufficient caloric output. African demographics don't appear to be having much of an issue regardless.
>>16349488Interactions between dust and plasma just get fucking weird in general.
>>16345664>even getting to Mars by conventional means takes years, on average 1 year waiting for a window and then between ½-1 year for the actual transferDepends on how much fuel you're waste burning to get their faster.
>>16345664>even getting to Mars by conventional means takes years, on average 1 year waiting for a window and then between ½-1 year for the actual transferDepends on how much fuel you're willing to waste burning to get their faster.
>>16351144>waste And that is the operative word here given how much more a brachistochrone trajectory would need.
>>16351187How much is your time worth?
Any /sci/entists going to DPP this year?
>>16351944I don't think I'll be able to, I'm actually getting interviews now and might have real job soon.
>>16351944Yes, but it's gonna put a deep ass hole in my pocket. Atlanta's pricey and registration has been jacked up again.>>16351951Congrats!
>>16352022>Congrats!I'm not they're just yet, but I'm becoming more optimistic.
>>16352117Still, you're putting yourself out there, anon. Good luck!
>>16351951Are you trying to look at stuff in your specific field or just general science/tech jobs?
>>16354299Both
>>16354309Where does one even look for plasma physics jobs?>t. starting grad school
>>16355980the same as all other science jobs>national labs>universities>tech corporations
>>16355980It varies a lot depending on what you specialize in. You’ll have a pretty good idea of what’s out there after attending a few conferences and by looking at where the past graduates of your group ended up.
>>16322204>that have some cogent explanations for outstanding problems in cosmology especiallyLel no. EUers don't even agree on any aspect of cosmology, they don't agree what causes redshift. Some of them say it's tired light, others point to plasma cosmology without even realizing it's an expanding cosmology. They love Arp, who had different ideas again. Without that you have no cosmology, and no framework to understand most of the universe. There is nothing "cogent" about a group who can't even convince each other. >a bunch of weird pseudohistorical bullshit. and often a staggeringly poor understanding of, of all things, geology.What they say of astronomy, cosmology and plasma physics is every bit as ignorant and pseudoscientific. The problems are the same across fields: a) they are totally unwilling to do deep research to understand the background of a field. b) They don't like math so don't do any real physics and make zero quantitative predictions. c) They are completely uninterested in testing their ideas against all the data out there. It's all just empty handwaving. >at least there's plasma cosmology, which is a bit less associated with the nonsense, but keeps some of the better ideas.It has been literally dead for decades, it is deeply in conflict with observations.
>>16356551yeah EU is just straight up quackery
>>16356551>They don't like mathFigures
>>16358911I mean... nobody *likes* math. We just sort of tolerate it.
>>16360654I stopped merely tolerating it when I had my first diff eq class
>>16351944No, there aren’t any sessions for what I do and the travel budget got eaten by EAPPC-BEAMS-EML.
>>16351944Yeah. Looking forward to the return of the ITER town hall session. Should be good for a laugh.
>>16362013>ITER town hallnani?
>>16362743Every year (or nearly), the ITER team sends some representatives to host a town hall event at DPP, where they update everyone on the status of the project, discuss what things are on track, what things aren't, what problems they're running into, what things are looking good, etc. Sometimes it's positive, but most of the time it's just them trying to explain the latest delays or lowering expectations for the project and then getting raked over the coals by a bunch of angry researchers who need to vent.ITER recently had to admit that the project is basically a decade behind schedule now, so some folks are expecting this session could get particularly heated (as much as a panel at a research conference can get, that is)
>>16360694Really? I thought they usually had at least a couple sections on beams and accelerators.
>>16356551>"Without that you have no cosmology">laughs nervously in Hubble TensionCosmology always has unavoidable epistemological problems. It's become a field of "proof by many examples," because it kind of doesn't have a choice - stuff's just too fucking faint and far away. Unfortunately, that makes its models fundamentally unfalsifiable in human timescales. It's just modeling, not proof.There are of course statistical arguments made, but statistics don't falsify. They're an approximation of where the line of falsification is, assuming both the validity of the phenomenological models and the applicability of the given statistical models. Such sets of results aren't consistent for how much redshift there is, let alone what its non-relativistic, non-Doppler component is, at the cutting edge of the field. They can't, in your words, "even convince each other."The popsci line of "we know it's just the cosmological constant" is damaging, IMO - nobody actually in the field I know of believes that a singular corrective constant to both our model and the universe is in fact what "dark energy" is... and THAT is the way LCDM models it, because that's the only way to fit it into the model.By your criteria here, 'cosmology' doesn't exist. They're not worthwhile criteria.>quantitative predictionsIf you were at all familiar with plasma physics, you'd know that's not currently possible even at small scales outside of certain tightly controlled domains, and might genuinely be impossible to realize mathematically. These systems don't even have numerical solutions without a complete description of turbulence, and that's before the introduction of electromagnetism - you can't just ignore fluid dynamics like you can for gravity/DE-only cosmological models.Cosmologists aren't shy about their hatred of charge and magnetic fields, and I can't really blame them - they're impossible to produce easy deterministic results with using current mathematical tools.
>>16356551>>16366308 (cont.)If you want it framed in more LCDM equation terms: solutions to the FLRW metric become intractable very rapidly if the electromagnetic component of the stress-energy tensor becomes relevant, because it requires a complete solution to the E and B fields - which is itself an intractable problem currently.Most of the expansion modeling assumes a small stress-energy tensor to reduce the problem to the Friedman equations, but this shortcut is completely lost if electromagnetism has a large impact on the stress-energy tensor.The B field is particularly problematic here for three reasons I can think of off the top of my head: One, it is itself dependent on the relative motion in the E field, and the "field lines" are known to be potentially chaotic (as in, literally like Lorenz systems). Determining the B field in many cases requires you to... already have the stress-energy tensor solved. Two, even charge-neutral bodies can produce and interact with magnetic fields, as in MHD. Three, The impact on charged particle trajectories by Lorentz forces well exceeds the impact of gravity, and knowing which bodies even have an impact and how requires internal modeling of both their hydrodynamics and conductivity - that's what MHD is.It almost immediately explodes into requiring a step-by-step *particle scale* many-body simulation - there are basically no computational shortcuts left, unless we someday solve turbulence, and that solution can be extended to conductive/ionized fluid systems.
>>16366308>Unfortunately, that makes its models fundamentally unfalsifiable in human timescales. Nope. Like the rest of astronomy cosmology is observational. By comparing models to the real universe models can be falsified. Most cosmologies that heave been proposed have been falsified. Static cosmology for example, stead state, CDM (without something like Lambda).>Such sets of results aren't consistent for how much redshift there is, let alone what its non-relativistic, non-Doppler component is, at the cutting edge of the field. That is not what the Hubble tension is. The Hubble tension is comparing the expansion rate calculated from a fit to the cosmic microwave background power spectrum in LCDM, vs local measures of the Hubble constant. These two things are not measuring "how much redshift there is". The only reason there is tension at all is because there is a quantitative model which predicts both of these things making it testable. >They can't, in your words, "even convince each other."Nope, not the same. Everyone studying LCDM, and even you know exactly what cosmological redshift is in the model. Expansion. It is defined for all to read. There is no ambiguity, there are no differing options because it's a model. Your argument doesn't hold water. And look how you've just cheaply tried to attack standard cosmology instead of defending EU from my criticism. Because what I said is true, there is no substance.>If you were at all familiar with plasma physics... might genuinely be impossible to realize mathematically.And yet plasma journals are full of simulations, with dozens of different numerical tools. Text books are full of equations and calculations. The real field of plasma physics doesn't struggle with the quantitative aspect of science. What a lame excuse.
>>16366308>solutions to the FLRW metric become intractable very rapidly if the electromagnetic component of the stress-energy tensor becomes relevantGibberish. There is no EM component in GR.> Determining the B field in many cases requires you to... already have the stress-energy tensor solved. Or you can just measure magnetic fields, with Faraday rotation and synchrotron radiation. Cosmological magnetic fields are constrained observation ally to be very small. At or below the order of 100 nG. If you calculate the energy density due to a field at that upper limit it is 5x10^-8 times the critical density. i.e. 10^7 times less dominant in energy density compared to matter. This is nothing.>Two, even charge-neutral bodies can produce and interact with magnetic fields, as in MHD. In LCDM the matter is dominated by DM, which has no charge. The bulk of the matter in the models doesn't feel any hydrodynamic or electromagnetic forces.
>>16366449>models can be falsifiedNot by epistemological standards. We're not talking "does the picture align," we're talking "there exists no example where the picture does not align."Observations provide evidence, not proof. This is something popsci doesn't understand - you cannot prove by example. Logic doesn't work that way.>expansion rateKnowing the rate is necessary to maintain the coherence of the distance ladder - and is literally how we arrive at "how much (cosmological) redshift there is for object X." You should know this, it's basic astrometry.>ExpansionYou've conflated the result - cosmological redshift - with its cause. It's a very common epistemological mistake in people who don't know what models actually are to the knowledge base (similar to the way most people don't understand that QM's mathematical framework doesn't actually tell you which interpretation is correct, despite being a perfectly valid framework). LCDM itself does not make this conflation - it just accommodates the observed effect with Lambda. It doesn't tell you anything predictively about where Lambda comes from. It's just a model, and it doesn't pretend to be anything else. People, on the other hand, pretend it's all kinds of things.>simulationsThe fact CFD exists isn't enough to prove the Navier-Stokes millennium prize problem - simplified models can exist without complete numerical solutions, but are only useful in domains where numerical (or ideally analytic) solutions can be found. Simulations of many-body systems can exist regardless of the existence of such solutions, but are prohibitively expensive for universe-scale quantitative results without substantial simplification (even the pure gravitational simulations make substantially simplifying assumptions).It's not so much a question of "can it be simulated" - more a question of "do we need a computer the size of the universe to calculate useful approximations of universe simulation results."
>>16320921https://patents.justia.com/patent/20240274303#historyHe got a patent for it for fusion reactor last month.Not exactly sure why it isn't showing up when I do patent searches on google though.
>>16366481>There is no EM component in GR.The electromagnetic stress-energy tensor is the EM component of the stress-energy tensor, which is part of the FLRW metric.It's not often used precisely because the gravity-only version can be considered homogenous and isotropic so long as the E and B fields are irrelevant.>Faraday rotation and synchotron radiationA statistically random magnetized volume would average out to no rotation over long enough distance, regardless of intervening B field magnitude; this is why it's useful for measuring magnetic fields close to particular objects (i.e. synchotron emitters), but doesn't really provide a good measure for the intervening, and thus the universal, B field strength.>matter is dominated by DM, which has no chargeYes, DM is utterly unaffected by electromagnetism ("no charge" isn't really sufficient to describe that IMO), but current understanding is that regular charge-carrying baryonic matter is still necessary to approximate the universe more accurately (DM-only sims have problems that adding baryonic matter helps solve). DM being ~5 times the mass of regular matter was considered enough to largely ignore the impact of baryonic matter until very recently. Since the EM force is as much as 10^36 times stronger than gravity, a tiny amount of ionization can have enormous impacts on said baryonic matter.
>>16367242>we're talking "there exists no example where the picture does not align."No we are not, that's not how models are falsified in observational science.>Knowing the rate is necessary to maintain the coherence of the distance ladderNope. We're talking about model coherence. Uncertainty in parameters due to limitations of current data is not the same as having no idea what redshift is. >You've conflated the result - cosmological redshift - with its cause. Nope. "in the model". Maybe try reading all of what I wrote instead of extracting single words. >"do we need a computer the size of the universe to calculate useful approximations of universe simulation results."Or you can simply work on what is feasible today. But this is where the EU crowd gave up entirely, why bother being quantitative when you can just wave your hands. If you claim your model is so complicated it cannot be quantified at all, then it is untestable and unscientific. >A statistically random magnetized volume would average out to no rotation over long enough distanceAnd yet rotation measures don't average out to zero. Depolarsation is another tool used to measure magnetic fields.
>>16367667>how models are falsified in observational scienceThey aren't. It's not falsification - a model has to be internally inconsistent to actually be falsified. Observational science doesn't work at the standard of proof, no matter how much you'd like to be able to prove by example.This is basic epistemology.>having no idea what redshift isWhat I said:>how much (cosmological) redshift there is for object X.Maybe try reading all of what I wrote.I haven't claimed it's not expansion, by the way.>If you claim your model is so complicated it cannot be quantified at all, then it is untestable and unscientific.See: CFD. It doesn't have quantified solutions that can be feasibly reached, just specific domains where it can produce quantitative results and an enormous number of domains where truly quantitative results are computationally infeasible with current tools. That's the quantitative difference here.A cosmology incorporating electromagnetic effects can't take the shortcuts that make gravity-only models tractable to simplification, making them computationally feasible.We're at a point where nobody has an algorithm to feed into a computer that is simpler than a collisional/EM field/gravity many-body simulation, and the many-body components alone are pushing at the limit of our best computers. We don't even know if such a simplifying algorithm exists.Computability and computational feasibility are not the same thing, but have the same result in regards to quantitative model comparisons.>And yet rotation measures don't average out to zero.Poorly worded - I mean the net effect on change in polarization angle relative to the original orientation. It means you can preserve net rotation from a regular field through a turbulent one... except it'll be more depolarized.>Depolarsation is another tool used to measure magnetic fields.Faraday depolarization erases the rotation magnitude. You want as little of it as possible to map the field.
>>16367667>>16368790Also, I want to be clear here - I'm not pro-EU. I'm just pro-"cosmology may need to get out of the habit of expecting the EM field to never have any meaningful impact."Dynamo theory has major unsolved problems, as all fluid theories do. That's not me saying it's wrong - that's me saying it cannot currently give the simple universal metric results that gravity-only theories can achieve. Gravity's unsolved problems can mercifully be sealed off behind event horizons. You have to dismiss all of fluid dynamics if you dismiss it on those grounds - it's not a cogent criticism.For EU, there are much easier ones - like how many of them are Young Earth Creationists.We're talking "the electromagnetic field changes isotope decay rates because I don't like your dates" levels of nonsense.From even a neutral epistemological stantpoint, that's a good illustration of why quantitative solutions that can be compared become less tractable quickly: more unknown parameters to the model. You can tune those unknowns to whatever predictions you'd like if you just define them to match whatever you observe and you avoid any internal inconsistencies (or at least... few enough that you can dismiss the discrepancies). Because that's the best empirical standard that observing examples can do for a model. Without proof that counterexamples cannot exist using axioms that are themselves provable (or at least proved to all practical standards - this is why experiment is closer to proof than observation; the available model testing space is not constrained by the sample size of observable examples in the environment, and ambiguities in observation are more tractable to clarification), you can't have falsification, let alone proof.Self-contradiction is the only means to actually falsify a model because it becomes proof of a counterexample, by showing that the model REQUIRES counterexamples to itself.Fuck, I wish more people understood epistemology.
I think the conversation here is straying a bit off-topic, anons.How about a nice paper on DT stabilities instead?
>>16368790>They aren't. It's not falsification - a model has to be internally inconsistent to actually be falsified. Observational science doesn't work at the standard of proofYou are dragging the conversation into pointless semantics. Empirical science doesn't contain proofs, and yet we still talk about falsification in terms of statistical confidence. I don't care if you don't like it, this is the terminology of the field of physical science. The Ptolemaic solar system was falsified by the phases of Venus. Steady state cosmology was falsified by the increasing number of quasars with redshift. >Maybe try reading all of what I wrote.Funny you whine about this while ignoring the rest of what I said.>>how much (cosmological) redshift there is for object X.I did respond to it. When I said "no idea what redshift is", I mean in terms of their cosmological model. What physical mechanism causes redshift. Without that you have nothing. >We're at a point where nobody has an algorithm to feed into a computer that is simpler than a collisional/EM field/gravity many-body simulation, and the many-body components alone are pushing at the limit of our best computers. We don't even know if such a simplifying algorithm exists.And never will because EUers have placed no effort in trying to simulate anything. There is no system of equations to even start with. You're making excuses for a hypothetical problem. They already claim to know how galaxies work, and stars, and comets. They clearly don't give a shit about simulations, or the scientific method. Numerical simulations aren't the only calculations in physics. There are lots of analytic calculations which could show self consistency and with observations, and yet they haven't bothered.>Faraday depolarization erases the rotation magnitude. You want as little of it as possible to map the field.Which is why people use compact sources.
>>16368820>>16368790>that have some cogent explanations for outstanding problems in cosmology especiallySo what did you actually mean by this?
>>16369036DT is unsustainable. We'll never be able to reliably produce enough tritium to keep up with demand.DD fusion is harder, but substantially more sustainable.Regardless, I'm pleased to see they're continuing to improve on general confinement stability.
>>16370050I might make a network then :)
use fission to achieve fusion
>>16370197I would but people get mad when I try to do that.
>>16303423I solved zpinch instabilityNo Im not willing to tell you how to do it I’m a misanthrope my discoveries die with me
>>16370930OH NO!Anyway...
>>16369036>How about a nice paper on DT stabilities instead?>tritiumYAWNWake me up when you make protium protium fusion work, you lazy shitty engineer. And if you just suck too damn much at life to build a protium reactor, then in my infinite kindness I AM WILLING TO ALLOW deuterium. But no more. The second you start yappin’ about tritium or "hELiUm ISotOpEs" is the moment you get your grants canceled and a good smackin’.
Why are plasmas always described as temperatures? Aren't temperatures a statistical distribution?Shouldn't we be able to accelerate ions at each other with a little more certainty than a bolzmann distribution?
>>16370976You can get different velocity distributions plasmas, but describing macroscopic behavior of those systems starts getting weird if you stray too far from MB distributions.
>>16370976>>16370983Dusty plasmas are particularly fucked when it comes to "temperature" because you also have to specify whether you mean the thermodynamic temperature of the molecules of the gas interacting with the molecules of the plasma, or the statistical temperature of the microparticles of dust interacting with each other.Sort of highlights why temperature isn't really a good physical property for describing things.
>>16303839Given that Chen is a mini computer and helps Ran I can see her writing books like that. The books Chen write are gold to us but are just children's homework for Ran.
>>16349578Everything is a fluid????
>>16373518>It's just fluids all the way down.
>>16303423do you guys like F. Chen's book?
I'm writing a thesis on plasma generation in a fusion reaction, and I was wondering if the good people here could point me towards reading material concerning the apparatuses themselves. Things like schematics, typical parts in the circuit, operating limits & standards etc. would all be helpful and much appreciated. Even surface level knowledge is appreciated, but the more detailed the source the better.
>>16303705diy/ohm? or do you mean more theoretical stuff?
>>16379833I'm interested to an answer to this post too
>>16379844nothing saying that it can't be both
>>16379938Mouf
>>16350349what am i looking at
>>16379844as much as i love /ohm/, i think solid-state physics discussion on there would be a bit limited, as well as frankly just out of place.
>>16380438I for one would appreciate your (assuming you were the one suggesting it) idea of a semiconductor generalt. Electrical engineer with an interest
>>16380012looks like a single layer of dust suspended in a plasma
>>16380438I'm interestedt.physicsfag
>>16369036>I think the conversation here is straying a bit off-topic, anons.That's a sign of a healthy general
Neat that my annual scan of the catalog overlapped with this thread.>>16341133Yep. Alas I don't know physics so I'm just trusting the boffins. The going copium on stability is that various advances will make even shitty plasmas/pulsed operation economical (for a power plant). Or something like that.>>16325541Yep, I can see it as I eat lunch. Or the job site that'll become it, anyway.The YouTube channel has a surprising amount of footage, by the way, including plenty of aerial shots, so you don't have to trust me. Certainly a lot of activity (as you can tell from the videos).
>>16378774Chen is pretty good. It's not exhaustive, but it's a good general summary of topics, and he's pretty approachable in how he presents the content.Piel is more graduate level. He's more exhaustive on topics, particularly fusion, but he also tends to do that same skipping of 'trivially obvious' steps that Jackson does in Electrodynamics that irks me. Still a good text though.Gurnett's actually pretty underrated. His book focuses more on space stuff and waves, but it's got some good introductory chapters as well.
>>16383339thank youI have Chen's book and I appreciated it (as an engineer, not physicist).Maybe I will challenge myself with the others later.
>>16382591glad for /ppg/ its nice to have more generals on /sci/ since most of the other threads are dog shit for actual discussion unless they are in general format
