To be honest this explanation is much clearer than "dumbed down" versions. I mean, this IS dumbed down a lot, but having numbers and key concepts that many other science communicators skip for the sake of attracting "wide audiences" really helps. This video is a gem, as well as the first part
I thought this was a good balance of not being too technical, while still expecting some ground knowledge. Good for people who know the gist of what fusion is and want to learn more about it.
This is really well made! the round numbers definitely helped my comprehension, as well as the regular comparisons to other types of fusion so we get a general idea of the relative differences. I especially liked the graph with the Sun's temperature and fusion rate compared with human-devised fusion methods.
The most surprising thing I learned in astrophysics was that the p-p fusion process gives off like no energy and takes about a million years to happen per reaction (on average). Then the D-T reaction happens within a second
Yes, since not yet half the hydrogen in the Sun has fused, each individual nucleus takes longer than the current age of the Sun to fuse. So a good thing for us overall.
I wouldn’t underestimate people’s curiosity in plasma physics and fusion technology. I don’t think you should minimize details on the technical aspects of the subject, so long as you can explain them well! Please keep it up and produce more when you can! *Subscribed*
please keep providing materials ! This is by far the best video on nuclear fusion there is on youtube. As a solid state physicist I would like to consider switching to this amazing field and those videos will hopefully be my starting point!
Ayyyy, i started out solid state and switched for my phd, we'd love to have you! If you want to work in diagnostics you can still work in a dark lab playing with optical components if you prefer it :P
I came upon your fusion videos today by way of random UA-cam recommendation. And I gotta say, I’m glad I found your channel, because your stuff is really well made. (Even aside from the raw pedagogical content itself, the production values are actually quite solid, even for as “basic” as most of the visuals you present may be. In other words: even if a big chunk of what’s presented is tables and graphs and diagrams, the tables/graphs/diagrams themselves are nicely done, and the animations and other little details are, dare I say, pretty “slick”.) You’re clearly someone with real experience in the field who has a solid grasp on the fundamental principles involved in the field of fusion; and your videos do a great job of striking a balance on complexity, to where someone like me with a pretty generalized undergrad-level background in physics can readily understand what you’re getting across while also not feeling like the video is talking down or just too oversimplified. Your ability to convey reasoned, realistic expectations with a healthy dose of skepticism lends a lot of credibility. I always appreciate seeing videos with real citations, too. And the occasional dash of humor here and there is great-up to and including the incisive bit about climate change denialists. I presume your most recent video likely caused a big spike in interest to your channel; and I’m glad for it, because that made it possible for me to find a real gem: a channel with great videos but disproportionately low visibility. Keep up the good work. 🙂
When they fuse mass within a Tokamak reactor, how do they get the fused mass out? Wouldn't the fused mass eventually dilute your reaction medium until the probability of fusing becomes unsustainable?
The way it works, even in current experiments, is that some of the ionized plasma is constantly recombining and cooling back to a gas at the edge of the reactor and being pumped out. Once pumped out, the helium "ash" is separated out. Fresh gas (pure fuel in the correct proportions) is pumped in. It is estimated that an atom of fuel on average will go round this cycle several times before fusing even in a future working power plant.
Wow! This video is amazing! This information is not easily available anywhere in this kind of detail. I really don't know how you were able to simplify the material the way you have. Thank you very much! Would love to hear more of this, do you have a Patreon?
@@ImprobableMatter Oh, what a shame, it seemed like a good place to discuss the topic and ask further questions... There's a distinct lack of internet spaces aabout fusion that have more than superficial hype...
@@antaresmc4407 There's so much inaccurate and shallow pop-science stuff it drowns out the good stuff. Channels like this are amazing but I only occasionally run into one unfortunately.
You're amazing dude. Very happy I found this channel, though you're crushing my hopes of us developing near-infinite energy, it's really nice to get an intimate understanding of how the science works.
Thanks for the video. I know next to nothing about fusion, and your last video was a great introduction - very well explained and easy to understand. Glad I found your channel as these videos come out
Stellarators are essentially tokamaks but better. The geometry of a tokamak causes a problem where the inner wall has a higher magnetic field than the outer wall causing charged particles to contact the outer wall and break confinement. Stellorators basically take the standard donut shape of a tokamak and twist it. This produces more uniform magnetic field lines which produces a much more even confinement field.
A version of this video (and all my other educational ones) without background music is available on my DailyMotion: www.dailymotion.com/video/x892b48 I wonder how many people unsubscribe after this video... Probably a bit too technical, sure to annoy cold fusion proponents and climate change deniers. Oh well.
video is great, really. consensus is not science. not long ago plate tectonics was ridiculed by the scientific consensus. not unsubscribing. but dont call me 'denier' please, just because i follow a different religion.
I really enjoyed the video. So valuable to see actual numbers and graphs that aid in understanding. I knew the p+B cros section was small, but this is the first time I have seen it compared to D+T so clearly. Plus the huge difference in energy gain. Guess I can cross off Eric Lerner and Focus Fusion. Too bad, I think his approach is very interesting.
Very much enjoyed the explanation, thank you for the time and effort you put into it! Always wonderful to have a complex topic broken down in an easy and accessible way, lets one gets one foot in the door and figure out where to poke around next!
No complaints from this stickler for accuracy in fusion reporting, a fine treatment all around. Though the climate change thing at the end seemed a bit weirdly tacked on. I would add though for those wishing to know more about WHY plasmas in thermo disequilibrium can never produce power, the relevant important paper here is the 1995 PhD thesis by MIT student Todd Rider: "Fundamental limitations on plasma fusion systems not in thermodynamic equilibrium".
I'm glad you approve. I noticed something that was missing: the scattering was meant to be for angles >4°, chosen to make it a round figure of 1000. There was something else minor I noticed only after uploading, but nothing too important.
Very good videos, I have watched your 3 part fusion series. I would love to see a deeper dive into the lattice confinement fusion if there is enough data to cover the topic yet. Is that possible for a part 4 or 5?
i wish you discussed the difference between tokamaks and stellarators. there are also so much more proposals like lasers shooting at tiny hydrogen pellets and liquid sodium cavitation reactors, it's very hard to find any actual information on their characteristics behind all the marketing fluff.
A wonderful video. Your explanation has allowed me to understand why companies such as First Light fusion might not work. The DeLorean statement is, however, heartbreaking.
I heard you say "every division on the y axis, the cross section changes by ten times" at 5:41. I looked it over but the increment of the y axis seems to be 100 times instead of ten. (0.01, 1, 100.) Hopefully someone can tell me if I made a mistake somewhere.
10:45 OK, I'm guessing here: The yellow one is an ion channel; if it's in plasma then it would be from a disintegrating cell. The other two look like enzymes of some sort?
Very nicely done. Lots of good facts shown with clear graphics and narration. I've been following the general topic for "a long time" but somehow missed the points about few explicit collisions lead to actual fusions but the momentum and KE goes from fast particles to slow ones anyway. For fusors, I thought the main problem was ions banging into the grid, draining KE from the beam and melting the grid.
The electrodes are certainly an additional problem for fusors, but even with magically robust ones the energy input to maintain a non-thermal energy distribution would outweigh the output from a practical electrical generator.
If accelerating particles or generating gamma rays is the issue, can't we simply use products of fission reactions? For example, in a lattice-confinement schema, can't we pump deuterium into fuel rods to act as a neutron moderator while also fusing and releasing more energy?
The extra fusion energy yield in such a case would be only a tiny addition to the power output of the fission reactor. Why add the extra cost and complexity when you already have a working fission reactor?
@@ImprobableMatter Oh, I get it. I'm more into fission anyway (plus solar, plus gas combined cycle gas turbines for peek demands and reserve capacity). Fusion reactors, like ITER, even if they ever get to the point of sufficient sustained net energy production which is economically viable, look so excessively complex, massive, and expensive to build and maintain, that only the richest countries can hope to afford. And that, I think, defeats the purpose entirely.
Excellent video with really clear graphics. You could explain why proton proton fusion has such a small cross section, instead of just giving a figure of 10-25 , and why the sun has to be so large . I have heard it said that the energy density in the sun is about that of a garden compost heap. Is this true? I have now subscribed
I didn't want to burden the video further with a discussion of why the cross sections are what they are, but you can look up things like the Gamow factor. The reason I did not give an exact value for the p-p cross section or the energy for its maximum is that it is actually too low to have been measured experimentally. Yes, it's true that the power density of the sun is very low (and a good thing too, or it would not have lasted as long as it has). The next in this series of videos will talk about stars and I will try to put in interesting details as usual.
@@ImprobableMatter Looked it up, and it IS complicated. Seems to be the product of two protons sticking together, and the simultaneous probability of a proton turning into a neutron .
Thanks for the clear explanation of thermonuclear fusion vs. beam-target and less useful variations. It helps me understand why confinement of the plasma is so hard, it has to be thermonuclear and sustained and controlled and kept away from the wall. Plus, you delve into the tritium processing issues, please make a whole video about the technology needed for breeding blankets and tritium processing.
This item is a balance between technical explanations and graphs to explain the challenges involved with Fusion. Fusion does work in the Sun, but trying to re-create this reaction (with a positive energy output) is very challenging. The article is quite interesting.
Neutrons will typically keep flying until they get absorbed by a nucleus, such as the walls of the reactor, the atmosphere, etc. For most nuclei, absorbing a neutron would make them radioactive, so this means that the reactor will need very strong shielding. Also, the neutrons carry a lot of energy and if they strike something like a piece of metal, they will smack the atoms which make the metal structure very hard. This means that a solid reactor chamber will begin to look like Swiss cheese and will become brittle.
5:18 Could that problem be fix by using quantum-locking to holding the atoms in place within the magnetic field. Would concentrating the beam onto the flux tubes make a higher chances of atoms collisions?
There is no such thing as "holding in place" when it comes to quantum physics. At the scales of the size of a nucleus, there is an uncertainty on the positions of everything.
@@ImprobableMatter The goal was to mitigate coulomb scattering and increasing the chances of the beam coalitions with particles. Analogy: Like hitting a free-floating ball in a pipe with a cue stick. If this would not work then do you know of any other possible way to mitigate coulomb scattering and increasing the chances of the beam coalitions with particles?
Thank you, I now understand this field a bit more even though quite a bit went over my head, I was left thinking that a Fusion Physicists role has a lot in common with herding cats 🐈🐈🐈🐈🐈 Great job, keep the videos coming 👍
The Wikipedia article appears correct: en.wikipedia.org/wiki/Rutherford_scattering Note one thing, however: the formula it gives is for a differential cross section (meaning not just the probability that it gets scattered, but scattered by a particular angle). To get the full cross section, multiply by 2 and then integrate with respect to Theta. Note that the differential and total cross sections become infinite at Theta=0, meaning that you are infinitely likely to be scattered by an angle of zero. This is because being scattered by an angle of zero is the same as not being scattered at all and all the atoms in your body are busy doing that all the time. You therefore have to define some minimum angle to be scattered by, which I took to be 4°. I was sure I put that in text in the video, but apparently not...
Thanks I will look at it. Where is the best to reach you? I think you mentioned a discord link but I didn’t find it. I really appreciate your work and I really find excellent to have a physicist doing such an amazing work for fusion science popularization!
Seems like it would be easier to engineer/develop a beam target that would have fusion rate of 1/100 vs. trying to control thermo nuclear plasmas in a magnetic bottle... ? Is there a plot that shows the Q for different beam targets?
@@ImprobableMatter thanks for the reply... still confused a bit, if your gain is 180:1 and fusion rate of 1/100 could be attained. Q would still be 1.8 right?
so in a thermonuclear device, particle beams are used to heat the bulk plasma so then temperature can fuse them together? just how hot can you make it this way? i thought RF fields are used to heat it up
Let me just check if I understand: the reason why higher temperatures are favorable is because that then makes the atoms more energetic (they move around more) and because of that they are more likely to collide with one another. Right? What I may be a little confused about is how the temperature can effect the effective cross-section of the atoms…. If at all. If someone can please help me or clarify any fault in my understanding, I would very much appreciate it.
The cross section is different when a given particle has a different energy. Generally, it is better for the energy to be higher. Higher temperatures mean that a particle has, on average, a higher energy. Therefore, at higher temperatures, particles have higher cross sections on average. That's one way to think of it.
I liked the gesture at the end. Take a clear stance and everybody knows, what he is subscribing to. The video is so attractive, you don't see the punch coming. Also: The people you mention are contrarians. Many don't shy away from accusing others of stupidity or even evil intent. Be blunt with those, they don't get respectful discourse anyway and will suspect you to be untruthful, if you try to establish productive communication.
Hi, what are your thoughts on "dense plasma focus" route that LPPFusion is pursuing? And a related question, what are your thoughts on molten salt reactors, will we be able to use our "spent" fuel for some thousands of years? Thanks
LPPFusion are claiming to use the p-B reaction, which as I mention is objectively much much harder to do, so I'm skeptical. With regards to MSRs, fission really is a mature technology so it's just a price argument. In actual fact, running a fusion reactor at an energy loss to transmute radioactive waste is an interesting proposal I will cover in a later video.
Re lattice fusion. There is a loophole. If the ground state of interstitial protons/deuterons is a resonant dipole-dipole mode (only possible if the effective well potential is sufficiently shallow, as in Pd and nickel [111] surface), the Jastrow repulsion factor disappears for the tails of the 2-particle correlation amplitude. Not many people know this...haha.
Excellent video. One thing I do not understand, however, is why couloumb scattering is a problem in a fusor. Will the energy exchanged between couloumb-scattering atoms not be preserved since the atoms are not scattered away and out of the system? And if it is contained within the vessel, where else can the energy go? Couloumb scattering is elastic as far as I can remember.
Once they scatter enough (even elastically, not losing energy) they will become a thermal plasma at a given (high) temperature. Once this is the case, it must be confined or lose this thermal energy by conduction to the walls, radiation etc. As you will see in the rest of the series, confining a hot plasma is hard.
Outstanding, earned my subscription. Content was really relevant and concise. We have been banging away at engineering hot plasma fusion for a long time. Given that fusion is a QM process, have there been attempts to increase nucleus tunnelling through the Coulomb barrier by increasing the de Broglie wavelength of the reactants ?. Is this what’s occurring in muon catalysed D-T fusion ?.
If two antimatter nuclei meet, they will annihilate and release a lot of energy. But since (fortunately) there isn't any significant amount of antimatter around, you would have to put in at least that amount of energy in to create it in the first place.
Thanks for the video. Just one thing I'd like to ask - you mentioned that nickel is the most stable yet when I searched youtube about all the space mumbo jumbo, a theory says that everything will be Iron? How is that possible? (I don't understand nuclear physics beyond the simple concepts so perhaps it's a dumb question) Also, do I see kirov reporting at 9:00?
Nickel 62 (28 protons, 34 neutrons) is the most stable, with Iron 56 (26 protons) close behind. So, these two are the final products of stars. Heavier elements are formed in things like supernovae. As I mentioned, just because energy can be released, it doesn't mean it will. The cross sections of reactions favor creating Iron 56, so this isotope is formed more out of the two above, even though Nickel 62 could release more energy.
Awesome video, great explanation! Really puts into the perspective how much work needs to be done. The ratio of how many fusions don't happen and instead the particles get deflected is dreadful. But perhaps it's just a great field to improve upon, just like semiconductors have improved immensely over the last 30 years. One has to hope, fusion will one way be viable, with tools currently unknown to us. On a closing note, I am not sure it was necessary to call out climate deniers at the end of the video. Such claims only serve to further divide and alienate the two camps and is not much related to the topic of the video. (I fully believe climate change is real)
We've come quite far, having outdone the Sun in terms of temperature. I'm sure we'll get there, just not as quickly as clickbait articles would have us believe. I put the bit about climate change, because I'd like to talk about renewables in a future video and still have a civil comments section.
Ah, I figured, looking forward to it! I just don't think it will be very effective. If your video about it gets recommended a lot, you will get a lot of new viewers. Just try to not get this undue "criticism" to you, don't get discouraged by it.
Great video, very educational. My only criticism is the music is very distracting. Maybe it isn't to others, but I prefer to concentrate on video without any distraction.
In the case of the easiest reaction, Deuterium-Tritium, 80% of the reaction energy is carried away by neutrons, which will stream out of the thermonuclear plasma. A blanket around the fusion chamber must be designed to absorb them, thereby capturing their energy as heat. This heat is extracted from the blanket and used to generate electricity with turbines similarly to a conventional power plant.
@@ImprobableMatter So is this, as yet, another unproven part of the fusion reactor process or is the absorbtion blanket a well understood process? Will the neutrons intereact with any of the confinement and plasma heating hardware, assuming the absorbtion blanket is around the outside of the reactor?
@@richardmarkham8369 Absolutely: the issue of neutrons is probably the greatest unknown currently for all fusion approaches. While it is theoretically well understood and tests of neutron effects have slowly been made, the exact engineering of a blanket has never been properly tested. Structural components and other vital parts of the machine are expected to be severely weakened by neutrons. People are slinging different comments about ITER, but one thing that is less discussed is that it will have several slots for different countries to test tritium breeding blankets in a realistic environment: fast neutrons and near a hot plasma.
Proton-Boron fusion, is it easier to get the required higher temperatures by simply using bigger devices? If temperature weren't a factor that would be the best option due to no electrons and commonly available ingredients, right? What would a 7 million square kilometer tokamak get us to in terms of temperature?
First of all, you would get an enormous construction and upkeep bill. Secondly, the hotter it is, the more energy it loses as bremsstrahlung radiation. So, it would cool down faster than the fusion reactions can heat it, and eventually the reaction would stop.
I don't think it is as discussed *in what form* energy is released from a nuclear reaction. Imagine a proton from the right colliding with a neutron from the left, both with the same momentum with respect to each other. If a deuteron (pn bound state) is formed, in which form the energy from the mass defect (between deuteron and p + n) is released? how would the release of that energy still conserve total monentum?
I think you've hit the nail on the head - the reaction will not happen if both energy and momentum conservation cannot happen. In the technologically relevant ones - D-T, D-D and so on - there are 2+ resultant nuclei, so both could be conserved. The reason for the way the energy is split between them is due to this. In the very unlikely proton-proton case, there is a positron and neutrino, so again both conditions can be met.
@@ImprobableMatter hmmm lets say in the end product you have 2 (or more) particles, are those particles get absorbed directly by the walls to extract power from fusion? does it matter if the particle is charged? or maybe energy can be extracted from the gamma rays (or maybe the gammas are losses?)
Ah ! (Just as a back of the envelope in the mind calculation, how big would a lattice confinement panel designed to do fusion for a generation ship to the stars have to be for enough random gamma rays to hit it? ((For a sci-fi story)) ?)
Check my numbers, but according to this data ( www.nist.gov/pml/x-ray-mass-attenuation-coefficients ) Erbium would absorb half of all gamma rays in that energy range for every couple of centimeters. 1/2 after 2cm, 1/4 after 4cm and so on. This does not factor how much the deuterium would absorb, but it's safe to say that very few gammas would make it deeper than 10cm into an Erbium panel anyhow.
Hi Improbable Matter, thank you for making these videos on fusion. I was starting to kind of get into the fusion hype train, although I am usually pretty skeptical about optimistic energy claims. I just have a couple of tangential questions. Firstly, could a fusion reactor with a Q total more than 1 but less than needed to generate electricity be useful for generating heat for industrial processes, so things like forging metal, preparing cement and glass, or heating oil shale and tar sands? Secondly, more of a general question, is EROI, Energy Returned On Invested, actually something that matters in relation to the efficacy of an energy source? It is often brought up by Peak Oil proponents, and is often derided by free market optimists. As someone who clearly has a strong background in physics, does it make any sense to you to use it ? Lastly, do you think it is likely that electricity generated by fusion will ever make up a large portion of the electricity, or even all of the energy used by humanity, within the lifespan of someone alive right now? Thank you for reading my long comment, and good luck with the future videos!
Thanks. To answer your questions: a fusion reactor which outputs heat is unlikely to be economical. You could use a heat pump which has over 100% efficiency, namely it can pump in more than 1 unit of heat for every unit of electrical energy, or use mirrors to focus sunlight. A better idea for a non-breakeven fusion plant might be generating neutrons to transmute radioactive waste. For sure, some sort of economics will need to be considered when we get anywhere near a working fusion reactor: how much energy does it cost to construct the original plant, how much the raw materials cost, even things like the cost of borrowing money. It's hard to definitively say what the future energy balance will be like. People have commented that I'm too pessimistic because apparently I "don't understand what an S-curve is". It's true that if fusion is developed in a timely manner, people already born could well see exponential growth of fusion plants until a saturation of the market. Very hard to make an accurate prediction when/if that will happen.
Studying quantum physics has given me a basic understanding which allowed me to appreciate how well this analysis boils down fusion to a few important factors without getting lost in the weeds.
@@ImprobableMatter ok thanks for the fast reply. I see a lot of people talk about fusion but almost nobody talks about muon catalyzed fusion so it's always intrigued me.
Cold fusion is real and has been demonstrated in a lab (muon-catalyzed cold fusion). It's just hard to imagine it ever being anywhere close to efficient enough to produce usable energy.
Consider: Protons are not static. Spins, velocity, phase of two protons must be complimentary for the protons to unlock the coulomb path matrix (not a barrier) The “fusing” is actually “a melding”, a sharing of quantum waves that results in one or more of the waves becoming redundant ( single waves in aneutronic fusion )
why do some private companies aim for proton boron reaction but none for deuterium deuterium reactions? it seems like d-d reactions would have some benefits.
Hello. Your work is insightful and well made. While your expertise lies with fusion are you also knowledgeable in matters of fission? If so there would be some interesting topics too.
It has been always a dream of mine to work in this field but certain circumstances led me to be a student in communication systems Engineering is there a way where I could self study this field like could you recommend to me any books or online courses...etc
"I am also in full agreement with the scientific consensus that human activity is rapidly altering the climate of our planet. I don't recommend subscribing to this channel if you think otherwise" Wouldnt you rather climate change deniers expose themselves to more scientifically accurate media? i know your videos havent been targeted at changing peoples opinion on the topic, but IMO i'd rather have deniers spend their time watching videos on this channel than listening to joe rogan.
To be honest this explanation is much clearer than "dumbed down" versions.
I mean, this IS dumbed down a lot, but having numbers and key concepts that many other science communicators skip for the sake of attracting "wide audiences" really helps.
This video is a gem, as well as the first part
They all serve a purpose, just like this video and I don't think they override eachother
My biologist ass managed to really enjoy and learn a ton, as you only need to grasp the basics in nuclear chemistry and thermodynamics to do so.
@@shenanigans2877 also this
I thought this was a good balance of not being too technical, while still expecting some ground knowledge. Good for people who know the gist of what fusion is and want to learn more about it.
So good for people who watched the previous video? 😉👍
I think this video is also good as a stand-alone presentation. You give a lot of new basic physics information not in the prior video. Good job!
This is really well made! the round numbers definitely helped my comprehension, as well as the regular comparisons to other types of fusion so we get a general idea of the relative differences. I especially liked the graph with the Sun's temperature and fusion rate compared with human-devised fusion methods.
The most surprising thing I learned in astrophysics was that the p-p fusion process gives off like no energy and takes about a million years to happen per reaction (on average). Then the D-T reaction happens within a second
Yes, since not yet half the hydrogen in the Sun has fused, each individual nucleus takes longer than the current age of the Sun to fuse. So a good thing for us overall.
I wouldn’t underestimate people’s curiosity in plasma physics and fusion technology. I don’t think you should minimize details on the technical aspects of the subject, so long as you can explain them well! Please keep it up and produce more when you can! *Subscribed*
please keep providing materials ! This is by far the best video on nuclear fusion there is on youtube. As a solid state physicist I would like to consider switching to this amazing field and those videos will hopefully be my starting point!
Ayyyy, i started out solid state and switched for my phd, we'd love to have you! If you want to work in diagnostics you can still work in a dark lab playing with optical components if you prefer it :P
I came upon your fusion videos today by way of random UA-cam recommendation. And I gotta say, I’m glad I found your channel, because your stuff is really well made. (Even aside from the raw pedagogical content itself, the production values are actually quite solid, even for as “basic” as most of the visuals you present may be. In other words: even if a big chunk of what’s presented is tables and graphs and diagrams, the tables/graphs/diagrams themselves are nicely done, and the animations and other little details are, dare I say, pretty “slick”.)
You’re clearly someone with real experience in the field who has a solid grasp on the fundamental principles involved in the field of fusion; and your videos do a great job of striking a balance on complexity, to where someone like me with a pretty generalized undergrad-level background in physics can readily understand what you’re getting across while also not feeling like the video is talking down or just too oversimplified.
Your ability to convey reasoned, realistic expectations with a healthy dose of skepticism lends a lot of credibility. I always appreciate seeing videos with real citations, too. And the occasional dash of humor here and there is great-up to and including the incisive bit about climate change denialists.
I presume your most recent video likely caused a big spike in interest to your channel; and I’m glad for it, because that made it possible for me to find a real gem: a channel with great videos but disproportionately low visibility. Keep up the good work. 🙂
When they fuse mass within a Tokamak reactor, how do they get the fused mass out? Wouldn't the fused mass eventually dilute your reaction medium until the probability of fusing becomes unsustainable?
The way it works, even in current experiments, is that some of the ionized plasma is constantly recombining and cooling back to a gas at the edge of the reactor and being pumped out. Once pumped out, the helium "ash" is separated out. Fresh gas (pure fuel in the correct proportions) is pumped in. It is estimated that an atom of fuel on average will go round this cycle several times before fusing even in a future working power plant.
You have one of the best channels on youtube. Thank you.
Wow! This video is amazing! This information is not easily available anywhere in this kind of detail. I really don't know how you were able to simplify the material the way you have. Thank you very much! Would love to hear more of this, do you have a Patreon?
Thanks. I hope to make several more videos in the series. No Patreon, but there is a Discord link in the pinned comments which I am trying out.
@@ImprobableMatter which pinned comment? Was it removed or something?
@@antaresmc4407 Oh, sorry, I did have a Discord, but I shut it down as it wasn't very popular.
@@ImprobableMatter Oh, what a shame, it seemed like a good place to discuss the topic and ask further questions... There's a distinct lack of internet spaces aabout fusion that have more than superficial hype...
@@antaresmc4407 There's so much inaccurate and shallow pop-science stuff it drowns out the good stuff. Channels like this are amazing but I only occasionally run into one unfortunately.
This is the honestly the best. Thank you. The world has been in need of a proper crash course on fusion energy for some time.
You're amazing dude. Very happy I found this channel, though you're crushing my hopes of us developing near-infinite energy, it's really nice to get an intimate understanding of how the science works.
Going through the playlist, and actually learning some new stuff.
Thank you.
Thanks for the video. I know next to nothing about fusion, and your last video was a great introduction - very well explained and easy to understand. Glad I found your channel as these videos come out
this channel is better than most out there, I'd say channel size is 1% of what it should be
I'd love to hear what your thoughts are regarding wendelstein 7x, or in general stellerators vs tomakaws.
Great video thanks!
Stellarators are essentially tokamaks but better. The geometry of a tokamak causes a problem where the inner wall has a higher magnetic field than the outer wall causing charged particles to contact the outer wall and break confinement. Stellorators basically take the standard donut shape of a tokamak and twist it. This produces more uniform magnetic field lines which produces a much more even confinement field.
Excellent content. Perfect amount of technicality while being understandable. I’m subscribed and notifications are on. Looking forward to more videos
Very concise and informative!
Beautifully written and delivered. This is such a gift. Videos like this are exactly why I am grateful that services such as UA-cam exist. Thank you!
A version of this video (and all my other educational ones) without background music is available on my DailyMotion: www.dailymotion.com/video/x892b48
I wonder how many people unsubscribe after this video... Probably a bit too technical, sure to annoy cold fusion proponents and climate change deniers. Oh well.
I'ld subscribe again if I could
video is great, really. consensus is not science. not long ago plate tectonics was ridiculed by the scientific consensus.
not unsubscribing. but dont call me 'denier' please, just because i follow a different religion.
One way to reduce global warming is to start mining on the moon. With that much cheese available, we could reduce our dependence on dairies.
Not to technical at all! Great video :)
Na the video was great
In my opinion easy to understand but i guess i don't necessarily represent the avarage
I’m new to the community but love the fusion content keep it coming!
I really enjoyed the video. So valuable to see actual numbers and graphs that aid in understanding. I knew the p+B cros section was small, but this is the first time I have seen it compared to D+T so clearly. Plus the huge difference in energy gain. Guess I can cross off Eric Lerner and Focus Fusion. Too bad, I think his approach is very interesting.
The video was well made, thank you!
Was going to give this video a thumbs up after watching anyway, but seeing "helium mix optimal" forced me to pause and do it immediately
I am so glad your channel exists! I have never come across such high quality explanations of fusion
Very much enjoyed the explanation, thank you for the time and effort you put into it! Always wonderful to have a complex topic broken down in an easy and accessible way, lets one gets one foot in the door and figure out where to poke around next!
No complaints from this stickler for accuracy in fusion reporting, a fine treatment all around. Though the climate change thing at the end seemed a bit weirdly tacked on.
I would add though for those wishing to know more about WHY plasmas in thermo disequilibrium can never produce power, the relevant important paper here is the 1995 PhD thesis by MIT student Todd Rider: "Fundamental limitations on plasma fusion systems not in thermodynamic equilibrium".
I'm glad you approve. I noticed something that was missing: the scattering was meant to be for angles >4°, chosen to make it a round figure of 1000. There was something else minor I noticed only after uploading, but nothing too important.
This is fascinating. I agree with the others -- this is a perfect mix of technical and approachable. Thank you very much!
Great video and a good balance between not too technical but also not too basic. Very happy I found your channel :)
Ahhhh the mention of cold fusion makes me feel young again. Flashes of the late 80's come rushing back :) - you make me feel like spring has sprung!!!
Excellent work here mate, well done. Very clearly explained!
Best video on explanation of fusion I've seen.
A very good video on fusion, very simple, informative and with cited sources!
Absolutely brilliant! I instantly subscribed.
Good video that goes more in depth and yet is very accesible
Great video, youtube should recommend your channel more.
These videos are phenomenal. Thank you for your work.
I absolutely looooved this
Very good videos, I have watched your 3 part fusion series. I would love to see a deeper dive into the lattice confinement fusion if there is enough data to cover the topic yet. Is that possible for a part 4 or 5?
Great series of explanations. And don't think the Kirov helium mix reference went unnoticed! ;)
i wish you discussed the difference between tokamaks and stellarators. there are also so much more proposals like lasers shooting at tiny hydrogen pellets and liquid sodium cavitation reactors, it's very hard to find any actual information on their characteristics behind all the marketing fluff.
Very clear and concise. Thank you!
A wonderful video. Your explanation has allowed me to understand why companies such as First Light fusion might not work. The DeLorean statement is, however, heartbreaking.
Excellent video. Understandable for someone in a different field
I heard you say "every division on the y axis, the cross section changes by ten times" at 5:41. I looked it over but the increment of the y axis seems to be 100 times instead of ten. (0.01, 1, 100.) Hopefully someone can tell me if I made a mistake somewhere.
Well spotted! I totally missed that between recording the audio and making the graphics.
10:45 OK, I'm guessing here: The yellow one is an ion channel; if it's in plasma then it would be from a disintegrating cell. The other two look like enzymes of some sort?
With the one on the bottom being a protein complex
So glad you made the follow ups
Very nicely done. Lots of good facts shown with clear graphics and narration. I've been following the general topic for "a long time" but somehow missed the points about few explicit collisions lead to actual fusions but the momentum and KE goes from fast particles to slow ones anyway. For fusors, I thought the main problem was ions banging into the grid, draining KE from the beam and melting the grid.
The electrodes are certainly an additional problem for fusors, but even with magically robust ones the energy input to maintain a non-thermal energy distribution would outweigh the output from a practical electrical generator.
If accelerating particles or generating gamma rays is the issue, can't we simply use products of fission reactions? For example, in a lattice-confinement schema, can't we pump deuterium into fuel rods to act as a neutron moderator while also fusing and releasing more energy?
The extra fusion energy yield in such a case would be only a tiny addition to the power output of the fission reactor. Why add the extra cost and complexity when you already have a working fission reactor?
@@ImprobableMatter Oh, I get it. I'm more into fission anyway (plus solar, plus gas combined cycle gas turbines for peek demands and reserve capacity). Fusion reactors, like ITER, even if they ever get to the point of sufficient sustained net energy production which is economically viable, look so excessively complex, massive, and expensive to build and maintain, that only the richest countries can hope to afford. And that, I think, defeats the purpose entirely.
Excellent video with really clear graphics. You could explain why proton proton fusion has such a small cross section, instead of just giving a figure of 10-25 , and why the sun has to be so large . I have heard it said that the energy density in the sun is about that of a garden compost heap. Is this true?
I have now subscribed
I didn't want to burden the video further with a discussion of why the cross sections are what they are, but you can look up things like the Gamow factor. The reason I did not give an exact value for the p-p cross section or the energy for its maximum is that it is actually too low to have been measured experimentally. Yes, it's true that the power density of the sun is very low (and a good thing too, or it would not have lasted as long as it has). The next in this series of videos will talk about stars and I will try to put in interesting details as usual.
@@ImprobableMatter Looked it up, and it IS complicated. Seems to be the product of two protons sticking together, and the simultaneous probability of a proton turning into a neutron .
Thank you very much for the video! I'm looking forward to the next one!
Thanks for the clear explanation of thermonuclear fusion vs. beam-target and less useful variations. It helps me understand why confinement of the plasma is so hard, it has to be thermonuclear and sustained and controlled and kept away from the wall. Plus, you delve into the tritium processing issues, please make a whole video about the technology needed for breeding blankets and tritium processing.
Finally a good video about fusion! and someone that knows what a barn (unit) is!
13:36 what about Muon-Catalyzed Fusion?
This item is a balance between technical explanations and graphs to explain the challenges involved with Fusion. Fusion does work in the Sun, but trying to re-create this reaction (with a positive energy output) is very challenging. The article is quite interesting.
Thankyou for a very succinct explanation of the whys and wherefores. I look forward to hearing more from you.
8:58 why is it bad that it gives of neutrons?
Neutrons will typically keep flying until they get absorbed by a nucleus, such as the walls of the reactor, the atmosphere, etc. For most nuclei, absorbing a neutron would make them radioactive, so this means that the reactor will need very strong shielding. Also, the neutrons carry a lot of energy and if they strike something like a piece of metal, they will smack the atoms which make the metal structure very hard. This means that a solid reactor chamber will begin to look like Swiss cheese and will become brittle.
@@ImprobableMatter thank you! :)
5:18 Could that problem be fix by using quantum-locking to holding the atoms in place within the magnetic field. Would concentrating the beam onto the flux tubes make a higher chances of atoms collisions?
There is no such thing as "holding in place" when it comes to quantum physics. At the scales of the size of a nucleus, there is an uncertainty on the positions of everything.
@@ImprobableMatter The goal was to mitigate coulomb scattering and increasing the chances of the beam coalitions with particles.
Analogy: Like hitting a free-floating ball in a pipe with a cue stick.
If this would not work then do you know of any other possible way to mitigate coulomb scattering and increasing the chances of the beam coalitions with particles?
Thank you, I now understand this field a bit more even though quite a bit went over my head, I was left thinking that a Fusion Physicists role has a lot in common with herding cats 🐈🐈🐈🐈🐈 Great job, keep the videos coming 👍
Thanks excellent video!!!
Where can I find how to plot the Rutherford scattering on top of the cross section diagram?
The Wikipedia article appears correct: en.wikipedia.org/wiki/Rutherford_scattering
Note one thing, however: the formula it gives is for a differential cross section (meaning not just the probability that it gets scattered, but scattered by a particular angle). To get the full cross section, multiply by 2 and then integrate with respect to Theta.
Note that the differential and total cross sections become infinite at Theta=0, meaning that you are infinitely likely to be scattered by an angle of zero. This is because being scattered by an angle of zero is the same as not being scattered at all and all the atoms in your body are busy doing that all the time. You therefore have to define some minimum angle to be scattered by, which I took to be 4°. I was sure I put that in text in the video, but apparently not...
Thanks I will look at it. Where is the best to reach you? I think you mentioned a discord link but I didn’t find it. I really appreciate your work and I really find excellent to have a physicist doing such an amazing work for fusion science popularization!
I did have a Discord, but it wasn't really getting much traction, so I closed it down. There is an email address in the channel description.
Fantastic video. I learned a lot more about fusion.
thank you so much for uploading!
Seems like it would be easier to engineer/develop a beam target that would have fusion rate of 1/100 vs. trying to control thermo nuclear plasmas in a magnetic bottle... ? Is there a plot that shows the Q for different beam targets?
If it has a fusion rate of 1/100 or worse, it will never generate net electricity. You just have an expensive heater.
@@ImprobableMatter thanks for the reply... still confused a bit, if your gain is 180:1 and fusion rate of 1/100 could be attained. Q would still be 1.8 right?
so in a thermonuclear device, particle beams are used to heat the bulk plasma so then temperature can fuse them together? just how hot can you make it this way? i thought RF fields are used to heat it up
A thermonuclear weapon? Watch the next video in this series. For magnetic fields and RF heating, watch the third one.
Let me just check if I understand: the reason why higher temperatures are favorable is because that then makes the atoms more energetic (they move around more) and because of that they are more likely to collide with one another. Right?
What I may be a little confused about is how the temperature can effect the effective cross-section of the atoms…. If at all. If someone can please help me or clarify any fault in my understanding, I would very much appreciate it.
The cross section is different when a given particle has a different energy. Generally, it is better for the energy to be higher. Higher temperatures mean that a particle has, on average, a higher energy. Therefore, at higher temperatures, particles have higher cross sections on average. That's one way to think of it.
I liked the gesture at the end. Take a clear stance and everybody knows, what he is subscribing to. The video is so attractive, you don't see the punch coming. Also: The people you mention are contrarians. Many don't shy away from accusing others of stupidity or even evil intent. Be blunt with those, they don't get respectful discourse anyway and will suspect you to be untruthful, if you try to establish productive communication.
Hi, what are your thoughts on "dense plasma focus" route that LPPFusion is pursuing? And a related question, what are your thoughts on molten salt reactors, will we be able to use our "spent" fuel for some thousands of years? Thanks
LPPFusion are claiming to use the p-B reaction, which as I mention is objectively much much harder to do, so I'm skeptical.
With regards to MSRs, fission really is a mature technology so it's just a price argument. In actual fact, running a fusion reactor at an energy loss to transmute radioactive waste is an interesting proposal I will cover in a later video.
Re lattice fusion. There is a loophole. If the ground state of interstitial protons/deuterons is a resonant dipole-dipole mode (only possible if the effective well potential is sufficiently shallow, as in Pd and nickel [111] surface), the Jastrow repulsion factor disappears for the tails of the 2-particle correlation amplitude. Not many people know this...haha.
Excellent video. One thing I do not understand, however, is why couloumb scattering is a problem in a fusor. Will the energy exchanged between couloumb-scattering atoms not be preserved since the atoms are not scattered away and out of the system? And if it is contained within the vessel, where else can the energy go? Couloumb scattering is elastic as far as I can remember.
Once they scatter enough (even elastically, not losing energy) they will become a thermal plasma at a given (high) temperature. Once this is the case, it must be confined or lose this thermal energy by conduction to the walls, radiation etc. As you will see in the rest of the series, confining a hot plasma is hard.
Outstanding, earned my subscription. Content was really relevant and concise.
We have been banging away at engineering hot plasma fusion for a long time.
Given that fusion is a QM process, have there been attempts to increase nucleus tunnelling through the Coulomb barrier by increasing the de Broglie wavelength of the reactants ?. Is this what’s occurring in muon catalysed D-T fusion ?.
I'm not aware of any serious attempts to lower the Coulomb barrier, except the lattice approach I mention.
can we use antimatter to fuse atoms ? it will overcome the repulsion problem
If two antimatter nuclei meet, they will annihilate and release a lot of energy. But since (fortunately) there isn't any significant amount of antimatter around, you would have to put in at least that amount of energy in to create it in the first place.
Thanks for the video. Just one thing I'd like to ask - you mentioned that nickel is the most stable yet when I searched youtube about all the space mumbo jumbo, a theory says that everything will be Iron? How is that possible? (I don't understand nuclear physics beyond the simple concepts so perhaps it's a dumb question)
Also, do I see kirov reporting at 9:00?
Nickel 62 (28 protons, 34 neutrons) is the most stable, with Iron 56 (26 protons) close behind. So, these two are the final products of stars. Heavier elements are formed in things like supernovae.
As I mentioned, just because energy can be released, it doesn't mean it will. The cross sections of reactions favor creating Iron 56, so this isotope is formed more out of the two above, even though Nickel 62 could release more energy.
Great question, I was thinking the same. Good to see the answer!
Awesome video, great explanation! Really puts into the perspective how much work needs to be done. The ratio of how many fusions don't happen and instead the particles get deflected is dreadful. But perhaps it's just a great field to improve upon, just like semiconductors have improved immensely over the last 30 years. One has to hope, fusion will one way be viable, with tools currently unknown to us.
On a closing note, I am not sure it was necessary to call out climate deniers at the end of the video. Such claims only serve to further divide and alienate the two camps and is not much related to the topic of the video. (I fully believe climate change is real)
We've come quite far, having outdone the Sun in terms of temperature. I'm sure we'll get there, just not as quickly as clickbait articles would have us believe. I put the bit about climate change, because I'd like to talk about renewables in a future video and still have a civil comments section.
Ah, I figured, looking forward to it! I just don't think it will be very effective. If your video about it gets recommended a lot, you will get a lot of new viewers.
Just try to not get this undue "criticism" to you, don't get discouraged by it.
Great video, very educational. My only criticism is the music is very distracting. Maybe it isn't to others, but I prefer to concentrate on video without any distraction.
A version without the music should be available here: www.dailymotion.com/video/x892b48
@@ImprobableMatter Thanks so much, that's much better.
Another excellent post
Another great video. Can anyone explain exactly how, if it ever happens, the above unity energy could be collected to generate electricity?
In the case of the easiest reaction, Deuterium-Tritium, 80% of the reaction energy is carried away by neutrons, which will stream out of the thermonuclear plasma. A blanket around the fusion chamber must be designed to absorb them, thereby capturing their energy as heat. This heat is extracted from the blanket and used to generate electricity with turbines similarly to a conventional power plant.
@@ImprobableMatter So is this, as yet, another unproven part of the fusion reactor process or is the absorbtion blanket a well understood process? Will the neutrons intereact with any of the confinement and plasma heating hardware, assuming the absorbtion blanket is around the outside of the reactor?
@@richardmarkham8369 Absolutely: the issue of neutrons is probably the greatest unknown currently for all fusion approaches. While it is theoretically well understood and tests of neutron effects have slowly been made, the exact engineering of a blanket has never been properly tested. Structural components and other vital parts of the machine are expected to be severely weakened by neutrons.
People are slinging different comments about ITER, but one thing that is less discussed is that it will have several slots for different countries to test tritium breeding blankets in a realistic environment: fast neutrons and near a hot plasma.
@@ImprobableMatter Many thanks for enlightening me! I can see why the jam jar with electrodes in was so much easier! Too bad it was bogus...
Brillant outro. Just had to toss that in there.
Awesome stuff! Very interesting. Felt like it was a 2 minute video
Proton-Boron fusion, is it easier to get the required higher temperatures by simply using bigger devices?
If temperature weren't a factor that would be the best option due to no electrons and commonly available ingredients, right?
What would a 7 million square kilometer tokamak get us to in terms of temperature?
First of all, you would get an enormous construction and upkeep bill. Secondly, the hotter it is, the more energy it loses as bremsstrahlung radiation. So, it would cool down faster than the fusion reactions can heat it, and eventually the reaction would stop.
@@ImprobableMatter yess o realized after I commented thank you!
I don't think it is as discussed *in what form* energy is released from a nuclear reaction. Imagine a proton from the right colliding with a neutron from the left, both with the same momentum with respect to each other. If a deuteron (pn bound state) is formed, in which form the energy from the mass defect (between deuteron and p + n) is released? how would the release of that energy still conserve total monentum?
I think you've hit the nail on the head - the reaction will not happen if both energy and momentum conservation cannot happen. In the technologically relevant ones - D-T, D-D and so on - there are 2+ resultant nuclei, so both could be conserved. The reason for the way the energy is split between them is due to this. In the very unlikely proton-proton case, there is a positron and neutrino, so again both conditions can be met.
@@ImprobableMatter hmmm lets say in the end product you have 2 (or more) particles, are those particles get absorbed directly by the walls to extract power from fusion? does it matter if the particle is charged? or maybe energy can be extracted from the gamma rays (or maybe the gammas are losses?)
LOL I find your dark sense of humour refreshing :D
I would really be interested, in your opinion of general fusions MTF approach
I'll touch on it in the next video in this series.
@@ImprobableMatter Awesome, I am really looking forward to it. Your videos are really informative
Ah ! (Just as a back of the envelope in the mind calculation, how big would a lattice confinement panel designed to do fusion for a generation ship to the stars have to be for enough random gamma rays to hit it? ((For a sci-fi story)) ?)
Check my numbers, but according to this data ( www.nist.gov/pml/x-ray-mass-attenuation-coefficients ) Erbium would absorb half of all gamma rays in that energy range for every couple of centimeters. 1/2 after 2cm, 1/4 after 4cm and so on. This does not factor how much the deuterium would absorb, but it's safe to say that very few gammas would make it deeper than 10cm into an Erbium panel anyhow.
Thanks for that (!) X
No problem, feel free to share a link to the story, or the book etc.
Really great content! Well done! 👏
Shot in the dark here, but are you able to explain the peak in the proton-boron beam target fusion cross-section at ~110keV?
Thanks for sharing your knowledge and expertise.
Hi Improbable Matter, thank you for making these videos on fusion. I was starting to kind of get into the fusion hype train, although I am usually pretty skeptical about optimistic energy claims. I just have a couple of tangential questions.
Firstly, could a fusion reactor with a Q total more than 1 but less than needed to generate electricity be useful for generating heat for industrial processes, so things like forging metal, preparing cement and glass, or heating oil shale and tar sands?
Secondly, more of a general question, is EROI, Energy Returned On Invested, actually something that matters in relation to the efficacy of an energy source? It is often brought up by Peak Oil proponents, and is often derided by free market optimists. As someone who clearly has a strong background in physics, does it make any sense to you to use it ?
Lastly, do you think it is likely that electricity generated by fusion will ever make up a large portion of the electricity, or even all of the energy used by humanity, within the lifespan of someone alive right now?
Thank you for reading my long comment, and good luck with the future videos!
Thanks. To answer your questions: a fusion reactor which outputs heat is unlikely to be economical. You could use a heat pump which has over 100% efficiency, namely it can pump in more than 1 unit of heat for every unit of electrical energy, or use mirrors to focus sunlight. A better idea for a non-breakeven fusion plant might be generating neutrons to transmute radioactive waste.
For sure, some sort of economics will need to be considered when we get anywhere near a working fusion reactor: how much energy does it cost to construct the original plant, how much the raw materials cost, even things like the cost of borrowing money.
It's hard to definitively say what the future energy balance will be like. People have commented that I'm too pessimistic because apparently I "don't understand what an S-curve is". It's true that if fusion is developed in a timely manner, people already born could well see exponential growth of fusion plants until a saturation of the market. Very hard to make an accurate prediction when/if that will happen.
I loved the video!
Studying quantum physics has given me a basic understanding which allowed me to appreciate how well this analysis boils down fusion to a few important factors without getting lost in the weeds.
Great video
Thank you for your videos.
You said there is no credible way to achieve cold fusion but what about muon catalyzed fusion?
Theoretically possible, but I still think it would have to be thermonuclear, just at a lower temperature.
@@ImprobableMatter ok thanks for the fast reply. I see a lot of people talk about fusion but almost nobody talks about muon catalyzed fusion so it's always intrigued me.
what about reversed field configuration
Very well put. After a few views, I think I got it.
Cold fusion is real and has been demonstrated in a lab (muon-catalyzed cold fusion). It's just hard to imagine it ever being anywhere close to efficient enough to produce usable energy.
Outstanding
Consider:
Protons are not static.
Spins, velocity, phase of two protons must be complimentary for the protons to unlock the coulomb path matrix (not a barrier)
The “fusing” is actually “a melding”, a sharing of quantum waves that results in one or more of the waves becoming redundant ( single waves in aneutronic fusion )
why do some private companies aim for proton boron reaction but none for deuterium deuterium reactions? it seems like d-d reactions would have some benefits.
Hello. Your work is insightful and well made. While your expertise lies with fusion are you also knowledgeable in matters of fission? If so there would be some interesting topics too.
It has been always a dream of mine to work in this field but certain circumstances led me to be a student in communication systems Engineering is there a way where I could self study this field like could you recommend to me any books or online courses...etc
"I am also in full agreement with the scientific consensus that human activity is rapidly altering the climate of our planet. I don't recommend subscribing to this channel if you think otherwise"
Wouldnt you rather climate change deniers expose themselves to more scientifically accurate media? i know your videos havent been targeted at changing peoples opinion on the topic, but IMO i'd rather have deniers spend their time watching videos on this channel than listening to joe rogan.
Yeah, you're probably right.