How nuclear fusion works (3) - magnetic confinement, tokamaks, stellarators
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- čas přidán 1. 06. 2024
- A look at the magnetic approach to achieving controlled thermonuclear fusion as a viable energy source.
Contents
00:00 - Introduction
00:27 - Particles in a magnetic field
02:52 - Magnetohydrodynamics
04:05 - Turbulence
04:45 - Recap
05:19 - Z-pinch
07:25 - Magnetic mirror
09:02 - Toroidal machines
11:48 - Heating
14:34 - Current
16:00 - Shaping
18:31 - H-mode
20:19 - Disruptions
21:15 - Machine walls
22:24 - Stellarators
23:03 - Wrap-up
References
[1] The first high-speed colour video from the COMPASS tokamak
• The first high-speed c...
[2] J. P. Freidberg, “Plasma Physics and Fusion Energy” (CUP 2010).
[3] T. F. Neiser et al., “Gyrokinetic GENE simulations of DIII-D near-edge L-mode plasmas” Physics of Plasmas 26, 092510 (2019).
[4] S. J. Zweben et al., “Edge turbulence velocity preceding the L-H transition in NSTX” Physics of Plasmas 28, 032304 (2021)
[5] Magnetic turbulence by Giannandrea Inchingolo (User:Giannandrea_Inchingolo)
commons.wikimedia.org/wiki/Fi...
[6] D. D. Ryutov et al., “Magneto-hydrodynamically stable axisymmetric mirrors” Physics of Plasmas 18, 092301 (2011).
[7] T. Sunn Pedersen et al., “Confirmation of the topology of the Wendelstein 7-X magnetic field to better than 1:100,000” Nature Communications 7:13493 (2016).
[8] N. J. Fisch, “The Alpha Channeling Effect” AIP Conference Proceedings 1689, 020001 (2015).
[9] B. Dudson, Magnetic Confinement Fusion Lectures
www-users.york.ac.uk/~bd512/t...
[10] The interior of Alcator C-Mod as seen from B port by Chris Bolin
commons.wikimedia.org/wiki/Fi...
[11] Plasma test in the MAST experiment at Culham Centre for Fusion Energy by user Dobbin74
commons.wikimedia.org/wiki/Fi...
[12] Video of MAST discharge 15872, UKAEA
[13] D. G. Whyte et al., “I-mode: an H-mode energy confinement regime with L-mode particle transport in Alcator C-Mod” Nuclear Fusion 50, 105005 (2010).
[14] J. Degrave et al., “Magnetic control of tokamak plasmas through deep reinforcement learning” Nature 602, 414 (2022).
[15] M. Rubel et al., “Application of Ion Beam Analysis in Studies of First Wall Materials in Controlled Fusion Devices” Physics 4, 37 (2022).
[16] V. E. Moiseenko, “First experiments on ICRF discharge generation by a W7-X-like antenna in the Uragan-2M stellarator” Journal of Plasma Physics 86, 905860517 (2020).
[17] Image of ASDEX Upgrade www.ipp.mpg.de/5035491/01_21
This channel absolutely deserves millions of views. I haven’t had a lot of time lately but I’m gonna binge every single video made by this channel, give a little algorithm boost
The problem is that this extremely information dense and interesting (genuinely) video is apparently not nearly as interesting as half the sh*t on CZcams shorts or Tictoc.
Thank goodness the channel exists and the same for the videos.
@@malayrojak All the more important to share it then, so that people with the knowledge and motivation for it can find it when they're searching for it online.
That's also why I built my channel to be a sort of encyclopedia of STEM-field (and more) related channels and videos on CZcams :D
Your boost might have resulted in my arrival here. So thanks ;)
It doesn't have that views because most people don't care about this.
It's a great video though.
Commenting for the algorithm hopefully this channel gets more recognition.
Agree, this man is a champ
This is by far the best fusion series I've seen on CZcams, it's clear you are an actual expert.
I became aware of the possibility of fusion power over 40 years ago when I was Primary School. Over the years I have seen many attempts to explain the developments in this area but after watching you video I can say that majority of these videos have failed to do this. Your video is the first that has help me get an effective understanding on the current state of this technology and to finally understand why there are so many reactors being built and researched. I truly love to see more of your videos on this subject. Thank you.
I learned more about magnetic confinement in this video than all the other fusion videos I have ever watched on CZcams combined. Thank you for creating such high quality content!
Whats your problem with teenagers reading news article headlines out for you and explaining how everything is either a major breakthrough or an hopeless desaster?
can't wait for the next video on swiss cheese
videos like these help me realize how little i actually understand our nuclear fusion efforts…
you don't understand how long I have been looking for information on fusion technology. Your channel is amazing
My friends often ask about my research, your channel has been an excellent source of diagrams for this purpose lol
The educational videos are now under a Creative Commons licence if anyone cares to use them.
Third time watching this in a few months and I'm amazed it only has 50k views
I need to watch this multiple times to understand it. This is quality content.
Thanks. All my videos are intended to be paused, rewound and rewatched. The captions (if you choose the ones supplied by me) are also meant to be the definitive transcript even if I ended up chewing my words and it's hard to say.
@@ImprobableMatter Yeah, I definitely paused and rewind a lot. I wished I realized earlier I should keep notes, to keep track of all the new information. I started it now, but will rewatch it all to keep notes. I am just a primary school teacher, but I hope to inspire one of my students to learn and maybe work on these problems :)
Amazing series about fusion! Hope you continue it; it fills the huge gap other videos (which are basically about the hype, and not the engineering challenges) leave. I love how you detail what exactly the problems are, and even tidbits such as the much hyped “AI is being used…” Hopefully the next video will deal with details about the geometry of the stellarator types; intuitively, it seems like they could be a better long-term solution, for they seem to have “less moving parts” in operation (although much more difficult to manufacture, but then it becomes more of a manufacturing problem than a coordination problem). Also, do the simplified calculations for energy input of the first video in the series include that used to create tritium (and the creation of deuterium pellets and other approaches)? Since it has to be synthesized, I wonder how much more extra energy that consumes.
Tritium production from Lithium-6 and the neutron coming off the fusion reaction is exothermic, so no problem there. Separating out the fuel isotopes, freezing them into a fuel pellet and so on is one of the (still somewhat unknown) energy costs of running a fusion power plant. Hence, the fusion energy gain Q must be at least greater than 20 for a commercial plant.
@@ImprobableMatter one hypothetical idea of spherical reactor that have two mirror magnetic rings that are placed on the bottom and on the upper part of reactor where magnetic lines goes through the center of reactor bottom up, and switches periodically in opposite direction following the switching direction of the rest of magnetic rings that are placed in a way that goes through equator of reactor and intersect with each other with the line that goes through the center of reactor and is perpendicular to the magnetic lines of mirror bottom up smaller rings but with higher magnetic flux. All this is happening in kind of circular constant switching on and off magnetic rings motion, very fast. In the center of the reactor is placed platinum or paladinum confinement entrenched with tritium and deuterium. It can be suspended by intital magnetic force that goes up and down, and gradually adding te rest and adding the speed of changing magnetic fields, while cental will hold it in a middle, other will also hold it but will also induce electrical currents which will heat up the confinement to plasma and even more to fusion. For confinement should be used nonreactive isotopes of this transitional metals. Later fuel should be added by lasers beams. I really wonder what do you think about this hypothetical configuration because you seemed very versatile in this topic.
You gotta talk about the Helion reactor and if its feasible or not, a good look at it's progress from an analytical content creator like yourself would really be helpful in getting an idea for how close or far Helion actually is to fusion power.
Best series on youtube to explain fusion technology and limitations that go beyond explaining how you need to smash two H atoms together at high temperature.
I cant believe I learned all this information for free. I learned so much, wow, thanks for making the video
Amazing work with the 4:48 intermezzo
Your casual dry almost deadpan random humor in these videos is hilarious.
These are really educational and well explained, and the humor is great.
Thank you for continuing to make these videos. Your channel absolutely deserves way more recognition
I love your videos thank you so much you have tahout me to be exstted jet realistic about fusion. Thank you so much
Amazing video thank you for making it
Thank you for this wonderfully informative video and praise the algorithm for recommending it to me.
I don't usually comment, but I have to say that this is the best video on CZcams about this topic. It was very clear, and it shows perfectly the complexity and engineering challenges that nuclear fusion faces. Is not easy at all, thank you.
I just want you to know how much I love these videos! I have watched the previous videos in this series about a dozen times now and I still enjoy them so much. Keep up the amazing work ❤️
Please, please, continue this video series. Abolutely love it. Very hard to find reliable, clear, and not too dumbed-down information on fusion.
These videos are great! I really enjoy the amount of good detail and good visual aid they include.
Yes yes yes. I been waiting for this part for months. I must have watched part one and two over twenty times. Fantastic. Thank you sir.
these videos are great, you always go into far more depth than every other channel that discusses fusion, thanks.
Bravo! That's a nice round-up of the mainstream MCF stuff. Thanks
"Who are you who is so wise in the ways of science?"
B seriously you got a phd in this stuff? I work at a tokamak as a diagnostics developer and you literally know everything somebody would need to know about modern fusion. Incredible content, especially with so many videos blowing up about fusion with terrible information, shilling for private companies and such.
I have a Masters in physics, PhD in Plasma Science and Fusion Energy and spent 2 years at JET as a postdoc. Now I study MHD in space.
Thank you for these fantastically informative and honest videos - really appreciated.
your videos are excellent. Please do the world a favour and up the production rate padre!
Another awesome fusion video. After every one I watch, I not only feel more knowledgeable, but more eager to learn. You taught the basics of magnetic confinement so well that before you presented the solution to the varying field line distances in a torus, I had already guessed it would involve twisting them. Keep up the awesome work.
Amazing video! Clear for people outside of the field
Fascinating, right round baby !
Thanks for the in-depth Explanation. The ELM video is Amazing.
This is on par with the best lecures ive seen, condensing extremly complex subjects like fusion physics into something tbat you can uderstand with a basic physics knowladge. Good work!
Solid lectures, thank you.
yes! i was hoping you’d post another one soon!
I hope you make a video about which reactor design is hopefully possible for fusion to come to reality. But great job for teaching fusion to laymen like myself. I hope you continue making videos regarding fusion.
very nice in depth explanation
Working on the HBT-EP reactor this summer for an internship. Love your videos 🤙
Very nice video. Just discovered your channel, and I'm gonna be supporting it now in the future. Also very nice to have all the references at the end.
Really looking forward to new videos on magnetic fusion! Excitement is also due to the fact I am starting a PhD in Fast Ion tomography in a few months :)
Nice! Which machine/research center?
@@ImprobableMatter We’ll mainly work on JET data, but not exclusively, within the plasma physics section of the DTU institute in Denmark
Thank you for this series.
Thanks for the great details
Thank you for creating this
What a great series of vidoes. I've never seen more easy to undesrstand yet thorough explanations of basic fundamentals of fusion techiniques and current limitations regarding different reactor designs. Well, I was lucky once to get some learning materials from a friend who had a Helmholtz Association lecture regarding fusion at his university, which was more comprehensive and interesting than what I could hope for, though was imaginably very hard to understand for someone who hasn't majored physics. So my big thanks.
If I may ask, are you going to make a video covering more about H-Mode and I-Mode in the future? I'm especially having a hard time understanding how ETB and ITB works, which seems to be quite fundamental in making I-Mode actually work and are cornerstones to various I-Modes being developed around the world.
ps. I've seen a comment before that you don't have Patreon, though would sending a yt super thanks work?
If I did a deeper dive into something like I-mode, I would probably do a livestream or interview with an expert (something I tried to arrange before, but didn't get very far). Might be something to try again.
@@ImprobableMatter That's exciting, should it happen! Really hope that you could find someone, looking forward for it.
This content is amazing. Truly.
love your videos, i'm pretty sure there isn't anything like this on youtube. many try to show to the masses how tokamaks work, and briefly mention the issue with instabilities, but that's it. i really appreciate the explanations, for youtube they seem very detailed, but i'm aware of how much isn't being said, anyway you do a great job at simplifying without making the subject too dumb
thanks a lot Sir highly educative contents !
Excellent video!
Really cool videos
I'm utterly facinated with this line of work & experimentation. I grasp what is being worked on perfecting currently but I'm still really curious about (How or What is the process of extracting power from it once it's figured out how to sustain good plasma fields?) Maybe I just missed it. Im sure the goal is to power a turbine thru thermal radiation but I'm just curious how that will connect with these machines. (I know the current ones are test machines, I'm just having a hard time visualizing how the plan to efficiently extract energy from the reactor will go?) I'm sure I'm just missing a obvious thing but I at least had to ask. *I absolutely love your channel BTW. I don't understand how it doesn't have millions of subscribers Because the quality of the science and the content is so good.
Excellent!
Well-Done
Would be interested in your thoughts about Helion Energy and their approach.
The only complaint about your videos I have, is that once I watch them I get constantly recommended inferior videos that aren’t nearly as in depth or scientifically accurate.
Thanks for making htese videos and clearing up the mess, I am a fan off the swiss cheese column :)
What about an adaptive magnetic field confinement technique? Instead of running a current through the tokamak plasma, you instead use computer controls to adjust the magnetic field by changing properties of the electro magnet. The computer system continuously adapts to any kind of drifts of magneto hydrodynamic instability. This would be a lot like computer controlled fly by wire in aircraft where the aircraft is inherently unstable in turbulence and therefore the computer must make small adjustments to maintain stable flight.
Could you make a video on stellarators alone? I would really like your insight on the matter as there are not that many videos on the matter.
That comet of the carbon facings is very od and interesting point thanks how know.
It does sound like a minor detail, but as mentioned in the video it took JET the last 15 years converting to a metal wall and then learning to get good performance with it.
@@ImprobableMatter Good things take practice.
Nice!
Regarding the individual deficiencies of magnetic mirrors and Z-pinch, have there been any attempts to 'cross the streams' and get a twisted field configuration as in toroidal designs, but without the quirks of toroidal geometry? I'm talking about a long magnetic mirror with added current running down the axis to twist the field. Or is the large size needed for decent confinement time just too much of an engineering / budgetary ask compared to tokamaks and stellarators?
Great work on this channel so far; deep dive channels like yours are a sorely underrepresented segment of YT
I'm not aware of it, but just to remind you of the potential drawbacks: driving current is not free (in terms of energy input and hardware) and the mirror would still probably have magnetohydrodynamic instabilities degrading performance.
@@ImprobableMatter That's fair enough, thank you!
Nice
Any views on salt reactors? Or thorium?
Great video, but sir I've got a doubt here, how is fusion ever be meant to be commercial viable if the only feasible fuel, is an isotope which we only have 30 kg of it available all around the world?
Once the fusion reactor is surrounded by Beryllium (neutron->2 neutrons) and Lithium6 (neutron -> Tritium), it will breed more Tritium than it consumes.
Hi there! Actually min 23:00 doesn't show the actual potential temperature. In 2022, a new ICRH antenna has been installed in W7-X, which is going to be used this year to increase the temperature significantly.
Do they use closed loop control of the magnets
Could you please cover General Fusions compression liquid metal fusion reactor? Or even a short synopsis of your opinion?
I think I mention it in part (2) since it is more of a cyclic inertial idea.
@ImprobableMatter What do you mean that a Stellarator has a potential Q value of infinity? From the equation this asserts that the energy input is zero, free energy? Please explain
Put in fusion fuel, get energy out; Q is infinity. What's the problem with that?
Have you seen Renaissance Fusion's stellarator concept?
What do you think about not neutralizing the ion beam so that the additional charge can be used as ohmic heating?
The magnetic field will deflect it; you'll never hit the plasma.
What's your thoughts on SPARC? Do you think they will deliver on their promises and have commercial fusion sometime in the 2030s or later?
Biased, but I am in favor of them overall. Certainly has some legs and will help the field along. My statement at 14:55 in one of my previous videos: czcams.com/video/JurplDfPi3U/video.html
Apenas a energia do nêutron pode ser aproveitada ou a energia do núcleo de hélio também pode ser aproveitada para produzir eletricidade?
Yes, but most of that power would come out through the divertor.
Great video. Regarding the Z pinch: one team at University of Washington (Shumlak et al) has recently proposed a sheared-flow-stabilized Z pinch to address the problem of instabilities. Experimental results are encouraging. This concept is now being developed in startup. Curious what you think of this approach.
Good luck to them, but I'm willing to bet that things will not be as rosy as the salespeople at the startup will paint them.
And most people don't even know we have any fusion reactors
How do we actually turn fusion plasma into electricity?
Wonder if we can tape power from the plasma through the diverters?
80% of the power comes out in neutrons, which must be captured and stopped by a blanket around the reactor. The blanket heats up and the heat is taken out to turbines as usual.
if the distance between the confined plasma and the reactor walls is large enough, can the neutrons lose speed before hitting the walls, preventing the wall from becoming radioactive?
They would only be slowed down by something the density of a typical solid or liquid, otherwise there are not enough atoms in their way to stop them. If it's a liquid, like heavy water, it would probably evaporate and quench the plasma. If it's solid, it is basically the first wall. There are some experiments which I will try to mention in the next video, to do things like cover the wall in liquid Lithium, which would stay on the wall, but protect it from the neutrons.
Ther is a reasion the door of the Rotating neutron source was 2 meters thick and made out of renforsed concreat.
What are your thoughts on project Pacer? Haha its a lot less complicated than magnetic confinement I suppose.
Epic
The instabilities mentioned remind me a lot of positive feedback. Have we still not figure out where this comes from in the MHD equation?
Maybe somehow we can find negative feedback mathematically to try to stabilize the plasma
So the particles travel along the magnetic field lines. I was under the impression that the particles were somehow repelled away from the sides of the torus. Interesting, makes more sense as it would be very difficult to not leave any gaps.
The diverter also seems like a logical place to have some kind of heat exchanger to extract thermal power from the reactor.
Perhaps I missed it, let's say they manage to produce more energy than it takes, it looks like that energy is in the form of heat from plasma deep inside the magnetic field, doesn't that heat have to be extracted somehow to make steam and turn a turbine or something?
80% of the energy comes out in the form of neutrons, which must be captured by a blanket around the reactor. The blanket heats up and that heat is transferred out where it will indeed power a steam turbine.
20:20 is this the so called dreaded "vertical displacement event"?
Yes, it is usually the main culprit with disruptions.
Now that Real Engineering has uploaded the video on Helion's fusion shenanigans i was wondering if you are considering making a video about it? Does it add up?
I think it will age about as well as this (now taken down) article from two months ago that said the following about Sam Bankman-Fried: "After my interview with SBF, I was convinced: I was talking to a future trillionaire"
web.archive.org/web/20221027180955/www.sequoiacap.com/article/sam-bankman-fried-spotlight/
@@ImprobableMatter Oh that's sad to hear. :(
For a chaotic problem you need a way to approximate its expected movements with better options of constraint
Great great contents!! Hope you do others of that in the future to maintaining updated the info on Fusion World! Thank you! 🤩👍🙏🏻
I think I just realized what the name of this channel, improbable matter, is referring to
It's the idea that radioactive elements are literally improbable forms of matter and that over time eventually they stop existing.
Is this the idea?
Yes: nuclei that don't occur naturally like Plutonium, certain plasmas like 150M°C a few meters away from room temperature, laser light and so on.
65 years ago, when I started University Physics the primitive state of knowledge allowed us to plan nuclear fission power generation and dream of plausible terrestrial power generation utilising nuclear fusion.
Now, at 80 and retired I am convinced that some time ago we had sufficient experience with numerous immensely expensive research results available to know that safe fusion power on a small scale has been demonstrated to be unrealistic but money keeps being wasted by researchers spinning stories to keep the dream alive.
Is there way to contact you personally? Do you have a patreon? I just have a question.
Let say you borrowed God’s superconducting magnets and you induced perfect currents in the plasma, would fusion occur? If the plasma is perfectly organized into helices for containment, will collisions occur? Is our quest for containment killing the reaction rate?
"Don't you see? God's superconducting magnets were with you all along through the power of friendship..."
But seriously, in short - better magnets would mean better confinement, better gain, and therefore a feasible power plant. Suppose we have (very rough numbers):
ITER - 10 Tesla on coil / about 5T in the plasma
MIT/Commonwealth Fusion reckon they can get the same performance from a much smaller machine with
SPARC - 20T on coil/10T in plasma
Therefore, if you could magic up 100T coils then you would probably solve all confinement problems. This is limited by the materials themselves, so you can't simply make an existing coil bigger etc.
You can never get particles into perfect helices, because as soon as you get more than one particle together they will begin to collide and become turbulent. You will always have turbulence like at 04:24 though it will be smaller the larger the magnetic field is.
Wow, Plasma Instability is a hugely complicated problem!
Flying saucer that runs on air.
If you collide two neutral beams at the focus of a laser that is a certain distance from a positively charged sphere, the electrons from the ionizing laser will go into orbit around the sphere and return to the laser focal point. Some of the ions will be trapped by the elevated negative charge at the focal point and orbit the focal point being more strongly drawn to the focal point than they are repelled by the positively charged sphere because they are closer to the focal point. A beam of electrons aimed at the focus through the center of the sphere can be used to refresh the electrons to maintain or increase the voltage at tge focal point.
An opposite configuration with ions orbiting a negative sphere has the problem that some ions will eventually crash into the sphere. The power is limited by the buildup of voltage in the direction of the sphere because of the orbiting electrons. But if multiple focal points are used and a certain excess of electrons over ions is maintained relative to the voltage of the sphere, a reasonable amount of power might be obtained.
This phenomenon of the charged particles returning to the point, might explain the asteroid that exploded over Russia on the same day that another asteroid was making a much awaited fly by. Pieces of colliding asteroids will tend to return to the exact point of the collision.
The assumption about the climate and the alleged crisis early in this video series suggests that there might be certain other questionable basic assumptions in this video series. Like the figures on the cross section of proton proton fusion. Trying to accomplish proton proton fusion without a dense surrounding plasma of neutrons, positrons, gluons, quarks and neutrinos as in the core of the sun might give substantially different results.
If climate science is an example, one might do well to have a certain amount of suspicion about certain basic assumptions.
Electrostatic confinement is mostly skipped over in this video except for the brief mention of a certain kind of fusor. Some say they know the Q of the Farnsworth fusor and why it failed to get net power.
A Q of 5 or 10 necessary to get net electrical power? Maybe with certain kinds of devices. But if half of the waste heat is recovered by the system, a Q near .5 for thermal energy for fusion energy over input thermal energy might achieve net thermal and electrical energy. ,
Using plates around a large narrow torus instead of magnets has a number of possibilities. If hydrogen gas is spun around the inside of tge torus fast enough to evacuate the center and compress a layer of hydrogen along the inner walls of the torus, the layer of compressed hydrogen could become a vast and profuse supply of ions and electrons that could be easily raised to fusion temperature by ionizing the gas near tge inner edge. The ions and electrons would be confined temporarily and when they did escape confinement they woukd tend to strike the gas at a point in front of an oppositely charged plate. Tge atoms ionized by the collision would then supply more ions and electrons to be driven in towards the center. When an alpha particle hit the surrounding gas, it would ionize zillions of atoms causing an accelerating chain reaction effect with the rate of fusion. profuse supply of ions and electrons and the facility of recovering the waste heat with a gas turbine might accomplish net power at much less than a Q of 5 ir 10.
Once the positive and negative plates are charged up to like a million volts, they require very little energy to maintain the charge. Most of the heat from a 10,000 watt laser used to ionize the ionization points could probably be recovered. If an excess of electrons is built up in the plasma, an off center offset to the ionization points would tend to make the plasma spin. The plasma and surrounding gas might spin at a much higher rate than a solid rotor ir turbine could spin it.
If the torus was filled with air, the centrifuge effect woukd tend to cause water vapor to accumulate at the inner surface of the spinning gas because of the centrifuge effect and because it is lighter than air. Even if the voltage of the plates could not fuse much H1, just the deuterium in the water vapor might be enough to drive it.
Hit us with some muon-catalyzed fusion theory!
This sounds like holding in helium with a bunch of strings
MFTF - my dream is that someday somebody makes a deep dive on the history of that project and its working principle
Whats stopping you from creating a quad style intersection with 4 torus style pipes sausaging into the quad intersection and repeated with a set number of these quad intersections along the length of the donut shape
Ribbon style rifling occurring on pipes at the quad intersect points stabilising as it gets sausaged
It wouldn't solve the problem but it would open up avenues of experimenting for new methods of adding constraints
"I won't go into the full mathematics. . ." Bless you, sir. Math makes my hair bleed.
But do the particles need the fields love? 🤔
also i hope to see liquid metals for plasma facing components one day
I think it's sad that Tokomaks are so much easier to work with. The Stellarator is such a cool concept.