1 00:00:00,180 --> 00:00:07,919 I'm supposed to talk about that and give you an introduction about how plasma is, how you make it on at the end, basically how to hold it. 2 00:00:07,920 --> 00:00:09,840 Because what I do is fusion. 3 00:00:10,200 --> 00:00:16,080 So what we try to do is basically keep it together for long enough that we can get it to be hot enough to get fusion out of it. 4 00:00:16,240 --> 00:00:22,800 Seasonality out of it turns out that we had a title before I ever started doing the presentation. 5 00:00:23,350 --> 00:00:27,340 And of these three things that I don't know how to make it because I might theoretician. 6 00:00:27,510 --> 00:00:32,940 So this was my when I get there but I just play a little bit how they come about. 7 00:00:33,150 --> 00:00:37,440 All right. So let me tell you what I'm going to do in this first book. 8 00:00:38,760 --> 00:00:42,890 First of all, I would like to explain why we need I mean, that is what we need to understand. 9 00:00:42,900 --> 00:00:51,390 And really and there are sort of reasons why the astrophysical plasmas, that is manufacturing plasma, that is plasma supports space propulsion. 10 00:00:51,960 --> 00:00:58,740 There is a bunch of publications I do fusion. So what I just plain and put forward is that is very important for fusion anything, right? 11 00:00:58,740 --> 00:01:00,080 So that will be the first part of the top. 12 00:01:00,630 --> 00:01:07,790 Then once we understand we need one one of these plasma outrageous bling, how, what they are, what their basic properties are. 13 00:01:07,800 --> 00:01:14,220 And basically because I'm I do theory how you model them what is the the equations that you use to actually describe them. 14 00:01:14,670 --> 00:01:23,040 And at the end because this is actually going to be in a way very slightly to what fusion I'll talk about one particular type of plasma, 15 00:01:23,220 --> 00:01:28,650 which in my book feel is really strong and that the classification of particular way because we're holding it with those magic fields. 16 00:01:28,950 --> 00:01:34,529 All right. So let's talk a little bit about why we need for fusion. 17 00:01:34,530 --> 00:01:41,630 This about burning, right? When you are burning coal or oil or anything to get energy, what you are doing is breaking balls, right? 18 00:01:41,650 --> 00:01:46,469 You play to get energy out of the bonds that form the molecules that are solid, 19 00:01:46,470 --> 00:01:50,090 that the bonds that form all for molecules are actually much less energetic. 20 00:01:50,100 --> 00:01:51,500 That the bonds of the nucleus. 21 00:01:51,510 --> 00:01:58,440 Right, the nuclear nuclei, these very specific and bonds, usually you can relate them to the automatic forces, not quite, 22 00:01:58,440 --> 00:02:08,009 but most of them you can make that that those bonds are due to this the forces that are so that the nuclear force, 23 00:02:08,010 --> 00:02:09,569 the strong force is much stronger than that. 24 00:02:09,570 --> 00:02:16,080 And you can see that just by thinking that it overcomes the repulsion that you have between two, two nuclear arms. 25 00:02:16,080 --> 00:02:21,990 Right. So if we're able to break those nuclear bonds, we can get much more individual reaction. 26 00:02:22,230 --> 00:02:24,540 This could be really a good thing to do. 27 00:02:24,960 --> 00:02:34,080 Now, when you are trying to to to bond, you need to take into account what you need to do to achieve that bonding. 28 00:02:34,080 --> 00:02:37,680 Right. I mean, when you are burning coal or oil or wood. 29 00:02:37,680 --> 00:02:45,509 Right, just spontaneously do that. You have to become a warrior on your overcoming this this this initial barrier. 30 00:02:45,510 --> 00:02:49,710 If you are getting a lot of energy out of it, usually have to overcome a much bigger battery of them. 31 00:02:49,950 --> 00:02:58,320 If you are bottom in, for example, to study a molecule, the molecular bonds, you got to have the reaction. 32 00:02:58,590 --> 00:03:03,960 That is the easiest amounts. The the nuclear fission reactions are the one we try to achieve. 33 00:03:04,410 --> 00:03:11,970 We have two isotopes of hydrogen, deuterium and tritium. And then if you hit them hard enough with each other, they fuse and you get helium. 34 00:03:12,450 --> 00:03:19,739 That one alpha particle basically on underneath them and you get huge amounts of energy of your of tens of mega electron volts, 35 00:03:19,740 --> 00:03:24,510 which is a million times what you would get from are from a typical reaction, 36 00:03:24,540 --> 00:03:31,230 a chemical reaction right now, because we need to overcome the barrier to actually get that fusion there, 37 00:03:31,530 --> 00:03:36,390 which we need sufficient energy in the particles that when they collide, you can overcome that barrier. 38 00:03:36,420 --> 00:03:45,569 Right. Turns out that when you try to do this, it implies that you have to have a nobody trinity one of these basically temperatures. 39 00:03:45,570 --> 00:03:50,910 So what you need is to have a temperature that is high enough to actually get these reactions going. 40 00:03:51,510 --> 00:03:55,559 But when you're modelling something is not sufficient to actually have a temperature, 41 00:03:55,560 --> 00:03:58,650 you have to make sure that the energy you produce in these reactions. 42 00:03:58,860 --> 00:04:02,550 If they see that when you are burning something, you feel water, right? 43 00:04:02,940 --> 00:04:08,639 It basically you kill the forest just like you are evaporating water and you are getting 44 00:04:08,640 --> 00:04:12,510 into the of the system and that energy doesn't go back into keeping reactor flowing. 45 00:04:12,750 --> 00:04:21,920 Right. So what we need to make sure is that we ice to ice isolate the system thermally to make sure that we produce close body to the system, 46 00:04:21,930 --> 00:04:30,440 keeps it hot and we keep getting reactions. Right. So that means we describe that in the, in the, in the field by a time we get it in cycles, 47 00:04:30,450 --> 00:04:38,140 which is how long you can keep the kind of these basically how long it takes for a particle that you put in the model to basically want it off, 48 00:04:38,220 --> 00:04:43,260 to be out. And then not only that, you want to get this going, you have to have enough fuel. 49 00:04:43,440 --> 00:04:46,259 So you have to have a number of particles on. 50 00:04:46,260 --> 00:04:53,010 And then that basically place like you need a density number of particles for them to get cubed to to get your your body going. 51 00:04:53,760 --> 00:04:59,940 If you actually try to see what that implies, if you want to make this commercial, you get this number. 52 00:05:00,350 --> 00:05:05,210 The first one is pretty daunting at 150 million degrees to get this going. 53 00:05:07,130 --> 00:05:14,190 This is ten times the capabilities of the sun, which means that the hottest place in the solar system is deep enough. 54 00:05:14,200 --> 00:05:18,770 You know, when he's running, right? This is it. 55 00:05:19,130 --> 00:05:28,670 I mean, this is the reason why we basically need a plasma at this high temperature to moderate plasma speeds, and that's why we actually need it. 56 00:05:28,820 --> 00:05:34,220 Here is a typical plasma that we experience of like lightning and things like that. 57 00:05:35,210 --> 00:05:41,260 All you need is to do a 20 particle spinning that you that's basically a millionth of the density of air. 58 00:05:41,270 --> 00:05:47,629 So you have this very cool thing that is very unusual. So in total energy that you get in the system is just ten years. 59 00:05:47,630 --> 00:05:50,510 That is, you have ten times the energy right now. 60 00:05:50,780 --> 00:05:58,030 So it's not I mean, it is very hot, but it's not particularly energetic on the time that you have to be holding this together. 61 00:05:58,400 --> 00:06:02,330 1 to 10 seconds. More on the second side and on the one side. But that's the ideal. 62 00:06:03,050 --> 00:06:07,010 So as you can see, let me just stop by 150 million degrees. 63 00:06:08,180 --> 00:06:11,120 This is not something you can teach, something easy to do. 64 00:06:11,550 --> 00:06:18,740 What we need is because even though it's hard, a lot of interviews, for example, like like fission, these basically this, this. 65 00:06:19,160 --> 00:06:23,030 If we take these, we get energy globally inexhaustible. 66 00:06:23,480 --> 00:06:30,290 You can get most of the fuel from seawater and actually doesn't have any long leaf radioactive waste. 67 00:06:30,950 --> 00:06:37,729 All right. So now these are motivation. We want to teach these fusion energy, but we need those temperatures. 68 00:06:37,730 --> 00:06:40,860 We actually up with the plasma. So what? 69 00:06:40,860 --> 00:06:48,799 These are plasma and sorry. Well, plasma ice things like you see neon tubes. 70 00:06:48,800 --> 00:06:52,450 These lightning is basically the actual universe there. 71 00:06:52,520 --> 00:06:58,339 What we see emitting that is a blossom, right? The reason that we got the name is because this guy, Langmuir, 72 00:06:58,340 --> 00:07:04,489 which is an American scientist working, I think in New York, was working on these neon tubes. 73 00:07:04,490 --> 00:07:08,960 And then what he noticed is that you could actually deformed if you only knew you want it. 74 00:07:09,260 --> 00:07:12,740 And that luminous stuff that was in the middle just full of the tube. Right. 75 00:07:13,100 --> 00:07:16,219 So he said that you could mould it and that's where plasma come from. 76 00:07:16,220 --> 00:07:19,010 Is the Greek for the mould, right. 77 00:07:19,430 --> 00:07:25,400 Turns out that this is normal because when you have a plasma 150 degrees, the listing thing does is actually ballpoint. 78 00:07:26,960 --> 00:07:34,700 But we inherited the name and that's what we work with. So what are the properties that define what a plasma is? 79 00:07:35,690 --> 00:07:39,770 It is a gas and by definition, usually we consider a plasma, 80 00:07:40,340 --> 00:07:46,490 a nice gas that is dominated by long range interactions over strange interactions, and that is what you write. 81 00:07:47,240 --> 00:07:52,520 These two things can be relax. People talk about astronomy called the plasma or money that plasma as well. 82 00:07:52,820 --> 00:07:55,880 But in general, when we are talking about plasma, this is actually what we're thinking about. 83 00:07:58,610 --> 00:08:02,750 I can discuss basically when you get hot enough, you get a plasma. 84 00:08:02,810 --> 00:08:09,650 The reason for that is that once the temperature is bigger, that you only see some energy, the electricity in the system, 85 00:08:09,650 --> 00:08:14,000 we just knocked it out and you begin to see some process and you get basically outgassing, 86 00:08:14,000 --> 00:08:17,670 which you dissociate electrons from the nucleus electrolyte. 87 00:08:18,110 --> 00:08:22,810 And that happens when your body you fact you have to be cold enough to get one 88 00:08:22,910 --> 00:08:27,860 indication of energy which is an electron will basically that's 10,000 kelvin. 89 00:08:28,100 --> 00:08:33,890 Once you overcome the temperature, then you get organised gas, you see emission and things like that. 90 00:08:35,690 --> 00:08:41,660 We have experience of them. For example, when you look at fluorescent lights, that's a plasma in there. 91 00:08:41,990 --> 00:08:46,610 It is pretty surprising to think that that thing might be at that high temperature, right? 92 00:08:46,760 --> 00:08:52,430 It would seem that you wouldn't be able to contain that in in a blast you right reason for this. 93 00:08:52,430 --> 00:08:54,350 But in reality what needs to be called is electrons. 94 00:08:55,250 --> 00:09:00,229 But you need to have whole audience in these what you need to know to to have electricity in the dark enough that when 95 00:09:00,230 --> 00:09:06,890 they collide with with an atom they knock out one of the electron and it starts to propagate all over the place. 96 00:09:08,000 --> 00:09:14,720 And then getting the electrons hooked on keep it down as cold is not so difficult in fact, because the electrons are very small mass. 97 00:09:15,170 --> 00:09:21,590 So what you have is like whenever you have a collision between this massive atom on an electron, it's like hitting a ball with a wall. 98 00:09:21,950 --> 00:09:25,309 It just bounces. And then when it bounces, it keeps its velocity. 99 00:09:25,310 --> 00:09:31,840 It basically gives you the rate. So electrons move, take momentum from their background ions but they want they want their energy. 100 00:09:32,000 --> 00:09:35,329 You've you to have these very hot electrons and it is this cold. 101 00:09:35,330 --> 00:09:43,630 These are in the system. This is not what happened last months because we go from 10,000, 100 million and medium Kelvin. 102 00:09:43,640 --> 00:09:46,040 Right. These are very different types of plasmas. 103 00:09:47,630 --> 00:09:53,750 How actually not experience how these plasmas come here you get lining is basically that you get a magnetic field in the system 104 00:09:54,050 --> 00:09:59,900 and this electric flux very selective that you have around when you play these electrons in the actually for long enough that. 105 00:09:59,920 --> 00:10:07,610 You have to get ready to knock out an electron. You put these two electrons, those two to each, and you have an avalanche. 106 00:10:07,720 --> 00:10:13,180 And immediately you get these very violent experiences of of plasma up here. 107 00:10:14,080 --> 00:10:19,900 All right. So it's on your guts. As soon as you go to the kind of temperature you have disorganisation. 108 00:10:21,880 --> 00:10:27,770 What else defines a plasma? You have the comparison between long range interaction and tolerate interaction. 109 00:10:27,790 --> 00:10:33,430 And I know I'm going to be a little bit I'll be more precise in a second about this, 110 00:10:33,550 --> 00:10:37,390 but just to start with, to distinguish between one and the other type of interactions. 111 00:10:37,630 --> 00:10:38,440 Think about the following. 112 00:10:38,890 --> 00:10:47,220 When you have a plasma is charts, and then you look at at a given point, you can see that it has some touch density and some current density, right? 113 00:10:47,920 --> 00:10:49,510 You could take as much as equations. 114 00:10:49,750 --> 00:10:56,080 You produce an electromagnetic field that is currently that is all over the place and interact with a piece of this here. 115 00:10:56,410 --> 00:11:02,680 Right. For this piece of plasma, because of its density touch on its current density, 116 00:11:02,680 --> 00:11:06,580 we interact with this little piece through mathematic fields that this one has produced. 117 00:11:07,000 --> 00:11:09,970 That's what we call the long range interactions in black. Right. 118 00:11:10,270 --> 00:11:17,230 But the other thing that happens is that you have two particles about charts and expulsion of they interact on a force. 119 00:11:17,830 --> 00:11:18,100 Right. 120 00:11:18,250 --> 00:11:26,620 And that would be the sort of the range that you can estimate how close you have to be for the particles to know that they are close to each other. 121 00:11:26,950 --> 00:11:34,080 And thus by using that equation there, what you can do is take the Coulomb potential and give it at least a B, 122 00:11:34,510 --> 00:11:41,020 and you have to make that equivalent to the energy of the object, which is their temperature right out of this equation. 123 00:11:41,020 --> 00:11:47,330 You actually get how close you have to be to actually see another electron on the line, both of you. 124 00:11:47,680 --> 00:11:51,069 Right. And you can see that that actually scales probably with energy. 125 00:11:51,070 --> 00:11:57,600 The more of a you have, the more difficult. It's actually to notice that you're close to anything because you just squeeze by an elastic. 126 00:11:57,700 --> 00:12:03,220 You really don't know that plasmas have very few of these interactions. 127 00:12:04,030 --> 00:12:08,020 And here's how you can see the first. The first I have two, two ways of looking at it. 128 00:12:09,940 --> 00:12:17,710 You have on the first one is if you take a particle and you draw on the sphere around, it would cease to be apart. 129 00:12:18,010 --> 00:12:19,389 You can ask how many of the particle. 130 00:12:19,390 --> 00:12:26,560 So we think that the sphere of influence right and then if you take them and particle to be much less than one this 131 00:12:26,560 --> 00:12:32,650 is basically kind of particles don't see all the particles they are just very far apart from from each other. 132 00:12:32,980 --> 00:12:38,410 Right. Another way of looking at the same thing, which is completely related, but there are people that like it better, 133 00:12:38,420 --> 00:12:42,790 is what is called the coupling constant gamma in which you take the energy, 134 00:12:42,790 --> 00:12:44,649 the kinetic energy of the particles, get the body temperature, 135 00:12:44,650 --> 00:12:54,129 and you divide basically by the typical Coulomb interaction between them, which is just taking the Coulomb potential at a distance. 136 00:12:54,130 --> 00:12:58,360 You put the average do something with the particles that you can estimate, even the density, right? 137 00:12:58,780 --> 00:13:02,470 The density to the minus one third if you the typical distance the particle subsequently took. 138 00:13:02,770 --> 00:13:07,300 That, for example, is very large. The potential between particles is tiny, but we need to get it. 139 00:13:07,630 --> 00:13:12,160 And both of these numbers are related. That is actually the other one. 140 00:13:12,730 --> 00:13:20,290 The other one. Right. That that makes sense. So you want to think about this in terms of, for example, got a solid to liquids, right? 141 00:13:20,560 --> 00:13:23,690 What happens is that particles don't interact with each other. 142 00:13:23,710 --> 00:13:27,650 They are basically a gas. If they would be closer together, then they would form. 143 00:13:27,770 --> 00:13:28,260 They would form. 144 00:13:28,270 --> 00:13:36,610 A lot of this stuff is what is called a plasma on form, something like it's more like a solid liquid you general effusion for sure we have. 145 00:13:37,180 --> 00:13:39,660 But on the study slide, this by definition is what we call a black, 146 00:13:39,670 --> 00:13:44,139 maybe fully the other type of plasma like organised gases that are extremely powerful. 147 00:13:44,140 --> 00:13:51,190 A lot of basically coal is only a couple of plasmas. As you can see, we have not very imaginatively named in the field, but that's not, 148 00:13:51,380 --> 00:13:59,830 you know, because these long range interactions are actually they don't belong here. 149 00:14:00,190 --> 00:14:05,410 When we model these plasmas, we can think of them kind of almost like a flute, right? 150 00:14:05,710 --> 00:14:10,720 What we're going to do is that we are going to take these tools of function to describe them. 151 00:14:11,020 --> 00:14:21,399 And we have the distribution function that gives you basically the the number of particles in position are with the prosody that you have right now. 152 00:14:21,400 --> 00:14:29,170 When we have those, by integrating in theory by number of particles, we can get the density of particles that we have. 153 00:14:29,830 --> 00:14:33,610 And if we look at the and integrate over that, we get the average velocity that they have. 154 00:14:34,960 --> 00:14:46,270 If you use that and you are the only species in the 64 species on the charts, this becomes the density and that here becomes the carbon density. 155 00:14:46,480 --> 00:14:46,750 Right? 156 00:14:47,200 --> 00:14:53,920 And then with all these we just put it in too much with equations and we can exert multiple situations and get that if my dick feels out of these, 157 00:14:54,520 --> 00:14:59,890 right? So we didn't say yes, take whatever current she said. 158 00:14:59,950 --> 00:15:04,149 If your current identity have in one place. I think I feel my dick feel and I see what happens. 159 00:15:04,150 --> 00:15:08,770 We thought in the other place. Now we have to believe that this crucial functions there. 160 00:15:09,760 --> 00:15:19,420 I need to do that. What we are saying is that if you have in this kind of deterministic way, we look at in an infinite mechanics, right? 161 00:15:19,960 --> 00:15:25,080 If you have a number of particles, at one point they see an automatic field that tries to be a field of particles. 162 00:15:25,090 --> 00:15:29,830 If they have the same position, extending the position and the same velocity will actually be always the same. 163 00:15:30,430 --> 00:15:34,120 So what you can say is the number of particles long places, right? 164 00:15:34,260 --> 00:15:37,659 That's that's basically what it is. And this is the classification. 165 00:15:37,660 --> 00:15:40,930 So let's just look at the right hand side. Right. 166 00:15:40,960 --> 00:15:46,000 What you have is an equation which has got to be fixed so that the value of the function 167 00:15:46,000 --> 00:15:49,920 is conserved along the characteristics and these characteristics of a particle like this. 168 00:15:50,590 --> 00:15:51,310 If you move, 169 00:15:51,340 --> 00:15:59,380 you move in a space with a bit of TV and you move in one of these space due to an acceleration that's that comes from the little magnetic fields. 170 00:16:00,880 --> 00:16:06,760 So like, if I didn't have this right hand side here, I would actually have caused the problem. 171 00:16:06,760 --> 00:16:09,910 And these longer interactions will be the only thing that we have. 172 00:16:10,240 --> 00:16:17,850 However, this muscle equations that they showed in the previous slide are quite small. 173 00:16:18,640 --> 00:16:23,500 These don't have like the bleeps in electric field that you get a potential of 174 00:16:23,500 --> 00:16:28,930 a smooth out those those singularities that you have that there are collisions. 175 00:16:29,170 --> 00:16:32,800 They are not the dominant piece of the physics in the plasma, but they are there. 176 00:16:33,130 --> 00:16:38,330 Right. And then you have to model that somehow. So what we have is a right hand side of collision operator. 177 00:16:39,040 --> 00:16:43,470 Statistically, these interactions between to touch particles when they get closer. 178 00:16:44,020 --> 00:16:47,640 Right now, when we go to the we come to an approximation. 179 00:16:47,650 --> 00:16:50,680 It doesn't exactly mean that these collisions are actually important. 180 00:16:50,710 --> 00:16:55,240 What it means is that the this is a gas that is very rare, 181 00:16:55,240 --> 00:17:01,899 that three or four particles meet in one place because the volume that the particle occupies given by that B parameter, 182 00:17:01,900 --> 00:17:06,520 how how far it actually gets is just really small compared to the whole volume of the plasma. 183 00:17:07,150 --> 00:17:13,180 Right. And what happens is that you have two particles to come together, but three, four or five is even better. 184 00:17:14,140 --> 00:17:19,990 So what happens is that the approximation turns out to be that you have only binary collisions but was quite two by two. 185 00:17:20,320 --> 00:17:24,250 They never get to be three or four interacting together on. 186 00:17:24,490 --> 00:17:29,620 And then that's what you get. Nobody gets out to be by linear. 187 00:17:30,790 --> 00:17:34,240 You go back a little bit, you notice there is something fishy about all this, 188 00:17:34,930 --> 00:17:42,340 which is that they treat in Coulomb interactions as if they were only binary collisions by the to they got before. 189 00:17:42,820 --> 00:17:50,050 However Coulomb interactions actually long range. So every particle, everywhere, it's not really a particle quite. 190 00:17:50,080 --> 00:17:55,950 So what has happened here that does not really matter because plasmas usually have the 191 00:17:55,960 --> 00:18:01,840 other problem which is what you talk these actually the natural tendency of anything 192 00:18:01,840 --> 00:18:07,000 that starts to be neutral negative particles that attract positive particles and then 193 00:18:07,030 --> 00:18:12,730 things we tend to be neutral that sort of most plasma satisfies two of our is satisfied. 194 00:18:12,960 --> 00:18:21,070 Well this is by definition basically these two properties, the typical tail of the plasma is violent, something which is caused by length of plane. 195 00:18:21,160 --> 00:18:27,310 In a second, what it is and the frequency of the phenomena that we worry about is much less than what we call the plasma frequency. 196 00:18:27,820 --> 00:18:33,760 When this happens, these natural tendency to neutrality will actually be very strong. 197 00:18:34,210 --> 00:18:40,180 And what will happen is that you take a volume of plasma, it'll be neutral, there will be no charge, almost in it. 198 00:18:40,430 --> 00:18:43,510 You cut it in half, there will be no chance of it, and you continue copy. 199 00:18:43,550 --> 00:18:49,450 And as long as volumes are bigger than that, Debye length will still be neutral. 200 00:18:49,720 --> 00:18:54,340 The plasma doesn't actually allow time specifically. Not not very much. 201 00:18:55,420 --> 00:18:56,020 Why is that? 202 00:18:56,920 --> 00:19:03,940 This look at what the like this what what you have is that when you have a plasma you have a bunch of positive or negative particle flow of the place. 203 00:19:03,940 --> 00:19:07,480 No, I can pick up positive touch. I'm putting the needle with light. 204 00:19:08,260 --> 00:19:11,440 That's my Red Bull here. Right. In an extreme case. 205 00:19:11,440 --> 00:19:15,250 Yes to yes to like if it's take this. 206 00:19:15,550 --> 00:19:20,140 What that does is that it takes all the positive particles, the awareness field around it, and expels them away. 207 00:19:21,130 --> 00:19:24,490 And then what you have is that you have a region affected by the thoughts, 208 00:19:24,910 --> 00:19:30,130 which is full of negative particles that try actually just cancel the positive touch you have in the needle. 209 00:19:30,640 --> 00:19:38,260 We can estimate the size of that is here by just simple, simple math here like the estimate. 210 00:19:38,770 --> 00:19:43,870 The first thing is that once this chart is sitting there, you have to set up a potential. 211 00:19:43,870 --> 00:19:44,979 In this case, it's positive, right? 212 00:19:44,980 --> 00:19:51,910 So the potential will be positive compared to the plasma to actually expelling positive particles or attracting another one. 213 00:19:51,910 --> 00:19:56,080 What happens in the plasma is that the agents are very heavy. So usually this is done by electrons. 214 00:19:56,080 --> 00:19:59,790 They are not very massive and they explicitly sucked in by. 215 00:19:59,850 --> 00:20:07,830 Positive touch. Okay, so what do you need? You need actually to have sufficient potential to attract enough number of particles into the field. 216 00:20:08,790 --> 00:20:12,280 If you have the potential, a different potential difference that was much smaller, 217 00:20:12,450 --> 00:20:17,219 much smaller than the table of electrons with a modified velocity at the beginning. 218 00:20:17,220 --> 00:20:21,270 And that is too high. I think within between now you had a potential that was much bigger than that. 219 00:20:22,170 --> 00:20:27,770 Right. What will happen is that everything would collapse into into the into the touch, which kind of hovered right there with your a. 220 00:20:28,620 --> 00:20:35,790 So what you have is that the jump between the outside of the sphere and the positive touch has to be of the order of the written table. 221 00:20:36,330 --> 00:20:36,620 That's the. 222 00:20:37,350 --> 00:20:48,620 Now that is created by the fact that you have a positive touch here and you have a bunch of electrons flying around into the sphere on the other. 223 00:20:48,690 --> 00:20:53,040 The agents will be influenced or like overcome by all the negative charges. 224 00:20:53,460 --> 00:21:02,100 You can then take an equation which tells you that the same of the of the potential has to do with the toxicity in the, in the plasma. 225 00:21:02,340 --> 00:21:12,659 And then just by our my estimate that leprosy and you can estimate by the potential difference divided by the the square and typical toxicities, 226 00:21:12,660 --> 00:21:16,900 the electron density that you played to people, the audience is the physical body that you saw. 227 00:21:16,950 --> 00:21:24,120 It's good to get an estimate and then that they're blaming the dielectric constant out of this and that you can get an estimate, 228 00:21:24,120 --> 00:21:34,470 which is called the dividing that actually turns out to be tiny, but usually dense enough that that actually is not unimportant. 229 00:21:34,740 --> 00:21:42,750 It's a very small number. So what happens is that even sometimes a touch of period, that chart is always shielded and you don't see it. 230 00:21:42,780 --> 00:21:49,260 Björn antibody length, which is tiny compared to the to the surface of the plasma and then important. 231 00:21:51,270 --> 00:21:57,300 So that's basically what a plasma you call the plasma when the plasma size is going to be by length. 232 00:21:57,690 --> 00:21:59,940 If that's not the case, you could call it an another plasma. 233 00:22:01,590 --> 00:22:08,310 You actually not only need to have a plasma bigger than than the than the size of the of the device length, 234 00:22:08,610 --> 00:22:14,390 you also need to have the phenomenon that you're studying to be its frequency, to be as one of the brightness. 235 00:22:14,430 --> 00:22:17,430 You have to allow the electrons to move within the sphere. 236 00:22:17,430 --> 00:22:21,960 If it's too fast, electrons coughing, it's to kind of move the kind of shield, right? 237 00:22:22,350 --> 00:22:26,280 So what you do is to estimate the time you take the electron thermal speed and 238 00:22:26,280 --> 00:22:30,930 you say how long it takes for electron to go from the outside of this year. To these you make that estimate, 239 00:22:31,170 --> 00:22:36,540 you will always call the plasma frequency and then you frequencies have to be more than the frequency, usually satisfied as well. 240 00:22:37,920 --> 00:22:47,670 And then the last one, which is very important later so that it works out really nicely, is you only need to be first to know the electrons they have. 241 00:22:47,780 --> 00:22:53,310 There has to be electrons in this field. If there is no electrons, they won't be able to come in a still, right. 242 00:22:53,670 --> 00:23:00,360 So what you have to do is take your particle, make us feel around it with the size of the device length and see how many electrons you have in there. 243 00:23:00,690 --> 00:23:03,570 And if you want shielding, there must be enough of them. 244 00:23:04,230 --> 00:23:09,360 So you have to have this number, the number of electrons, this is the electron density to be bigger than one. 245 00:23:09,900 --> 00:23:13,379 And you remember the coupling parameter gamma and finally four. 246 00:23:13,380 --> 00:23:20,070 Turns out that that has to be big for plasmas two to be quickly couple so that 247 00:23:20,070 --> 00:23:26,040 that number when that's big you have plenty of electrons in the device for you. 248 00:23:26,550 --> 00:23:31,120 All this has to do with the fact that both excellent potential and device for you to have to do with the reality constants, 249 00:23:31,170 --> 00:23:34,350 densities, temperatures and all works out to be like that. 250 00:23:34,530 --> 00:23:39,030 So when you have our we can double platinum which is very useful. 251 00:23:39,690 --> 00:23:45,929 We have literally have plenty of electrons to fuel and that actually solve our problem about the long 252 00:23:45,930 --> 00:23:54,059 range interactions because what happens is that through long range that action should talk to everyone, 253 00:23:54,060 --> 00:23:59,820 but they don't get farther than device length because the particle, any particle outside of the device length won't see another particle. 254 00:24:01,020 --> 00:24:07,679 Right? So our expansion actually turns out to be based on the fact that we have enough filters in the 255 00:24:07,680 --> 00:24:12,990 device length to shield any charge and then the interaction that's gone beyond the device length. 256 00:24:13,320 --> 00:24:14,190 With that in mind, 257 00:24:14,460 --> 00:24:22,830 we can actually they got equation and divided into the motion due to long range on these binary collisions due to the typical long interaction. 258 00:24:26,460 --> 00:24:31,260 Okay, we have a plasma, we know why it works like more or less. 259 00:24:32,070 --> 00:24:36,000 And then we want actually to get fusion and this is where we're going to magnetised plus. 260 00:24:36,750 --> 00:24:42,990 So how can we get I said that you need some temperature, some timescale in which particles have to stay in the plasma. 261 00:24:43,560 --> 00:24:52,080 And we need actually some of this. Right. And there are different approaches you can imagine by doing this, you have the do not confine approach. 262 00:24:52,860 --> 00:24:58,740 If you cross and you get energy fast enough out of it, you don't need to worry about how long it takes to get it right. 263 00:24:59,720 --> 00:25:05,990 He is what unreachable is. So we get future these the beginning of one of the beginning of those tests there. 264 00:25:06,470 --> 00:25:16,640 So there is a lot of energy in the actions. What they do basically is they they they brutally explode an atomic bomb to compress completely steam 265 00:25:16,730 --> 00:25:23,120 fast enough to get these things to compress and get the temperatures to get the reaction going. 266 00:25:23,360 --> 00:25:24,230 And that's how things are done. 267 00:25:25,370 --> 00:25:35,509 There is a side to that is like another approach to nuclear fusion energy, not not bombs, but this is usually the same idea. 268 00:25:35,510 --> 00:25:40,690 But instead of using an atomic bomb to compress, they use lasers. And that in the second point in fusion approach. 269 00:25:40,700 --> 00:25:46,160 Right. That's one one thing one would think, well, 270 00:25:46,940 --> 00:25:55,159 I can actually try to find out a material to hold this thing together in it and keep it keep it in place of having to do something. 271 00:25:55,160 --> 00:26:02,300 That's why you going to start. Turns out that that's not possible, not only because materials more than like 100 million degrees in general, 272 00:26:02,330 --> 00:26:05,540 they usually get damaged and stuff like that is because you actually kind of get that high. 273 00:26:06,230 --> 00:26:09,380 What happens is that you have this very dilute plus a lot of energy. 274 00:26:09,620 --> 00:26:15,350 They not only bomb the material, but all that energy sucking through the material and you basically lose everything. 275 00:26:15,360 --> 00:26:21,140 So I actually at some point before working on fusion, I work on plasma thrusters for space propulsion. 276 00:26:21,620 --> 00:26:24,680 And in both cases you had a wall that was containing the plasma. 277 00:26:25,130 --> 00:26:28,640 You actually get at most of 100,000 Kelvin in those cases. 278 00:26:28,640 --> 00:26:30,440 So it's very difficult to get to the hundred million. 279 00:26:30,440 --> 00:26:37,399 That is a factor of a thousand between what you can get without containing it on what you can get into in places like these or what. 280 00:26:37,400 --> 00:26:40,610 I talk later. Another possibility is gravity. 281 00:26:42,380 --> 00:26:45,980 The that will happen in the stars. You have a stellar size kind of object. 282 00:26:46,190 --> 00:26:50,060 You can get fusion out of it. Obviously, that's not both feasible on earth. 283 00:26:50,420 --> 00:26:53,930 And then we have the last one mighty confinement, which is, I think the best one, 284 00:26:53,960 --> 00:26:58,070 not only because the work within that there is that is good reasons to to argue for it. 285 00:26:59,210 --> 00:27:04,700 And it is basically other thing you have beyond probably on this for me, you're wrong or I stop. 286 00:27:05,000 --> 00:27:16,230 So how does this work? It works because once you have a very strong magic feel in your plasma, they behave differently. 287 00:27:17,800 --> 00:27:24,730 And I will talk about how how different that how that behaviour is different, you know, in a second to make connection to what they say. 288 00:27:24,730 --> 00:27:29,020 The plasma ice is very important for Magnetisation but the plasma is quite a neutral. 289 00:27:29,980 --> 00:27:35,530 Right. If you were to take just like you have naked charges and you had problems with it and you 290 00:27:35,530 --> 00:27:40,899 estimated how much the magnetic force is compared to the to the to the electric force. 291 00:27:40,900 --> 00:27:47,950 Naively, what you would find is they are related by the level of the of whatever you are worried about, divided by the speed of light. 292 00:27:48,220 --> 00:27:51,340 Right. Which would mean that in general, we don't have a lot exotic particles. 293 00:27:51,340 --> 00:27:54,550 Usually in the confinement. These would be really tiny. 294 00:27:55,270 --> 00:27:56,490 The fact that have tons of lead, 295 00:27:56,530 --> 00:28:05,320 basically shielded to be too weak of extent means that the electric field is more than you expect and you can make that light, 296 00:28:05,410 --> 00:28:08,740 which is very important that you have washing in these in these cases. 297 00:28:10,060 --> 00:28:19,840 So what we're going to play now is how do plasmas behave once you have a properties beacon of competition on the scale and on a small Antarctic, 298 00:28:19,840 --> 00:28:23,530 which is more on a certain frequency, and that's when the plasma is magnetised. 299 00:28:25,730 --> 00:28:33,640 So what happens is that once you have a strong magic feel, the particles go and they go what is called a motion. 300 00:28:34,270 --> 00:28:37,940 I'm pretty sure you probably saw this. A lot of you saw this at some point. 301 00:28:38,360 --> 00:28:46,040 These are competition between a situation in which you particles don't have a cinematic feel and a situation in which you have a uniform, 302 00:28:46,460 --> 00:28:50,970 a straight line, maybe feel going through the plasma. And you obviously have these particles. 303 00:28:51,030 --> 00:28:56,180 You see any force, if one might feel they're just going straight lines to the wall, bounce back and forth, back and forth. 304 00:28:56,210 --> 00:29:02,500 Right. If you put a strong feeling system, what particles tend to do in this one is straight is just. 305 00:29:02,510 --> 00:29:07,090 They have galaxies around them. Ideally lines on are basically trapped within. 306 00:29:07,310 --> 00:29:17,090 Right. If you see what these looking is composed of is basically a circular motion in the plane to the magic feel and a free motion parallel to it. 307 00:29:17,720 --> 00:29:21,380 The reason for that is that the magic feel doesn't accept any force along it, 308 00:29:21,830 --> 00:29:27,900 so the particles will just be free to flow along them on and then across of it. 309 00:29:28,190 --> 00:29:35,690 But these are a force that is perpendicular to the velocity. Yes, I reminded of how to estimate the general radiation. 310 00:29:35,690 --> 00:29:39,230 What you do is that you estimate the centrifugal. 311 00:29:39,470 --> 00:29:45,950 You basically get the centrifugal force of having a superior motion, a plane with a radius rule that you have to determine. 312 00:29:46,610 --> 00:29:51,170 Right. And then you make that equal to the mighty force that you have in the system. 313 00:29:51,800 --> 00:29:58,700 By making that estimate, you can actually get what is the radius, which is the size, the reason, duration of those galaxies. 314 00:29:59,450 --> 00:30:05,600 And you can see now why magnetised the commoditized plasmas, if you have a mighty strong enough, 315 00:30:05,750 --> 00:30:09,110 you can make these already small enough compared to essentially the machine. 316 00:30:09,380 --> 00:30:15,770 And then what you see is kind of the particles are like beads that are for the magnetic field and they just go back and forth. 317 00:30:16,070 --> 00:30:24,380 You might feel on this the cold air that you have your plasma, 15 million degrees is very hot, actually. 318 00:30:24,830 --> 00:30:27,469 The more mighty food you need to keep it together. 319 00:30:27,470 --> 00:30:36,110 And that's why in experiments we get to some of the highest magic philosophy for because we'd like a five Tesla student, ten Tesla sometimes. 320 00:30:36,110 --> 00:30:44,900 Right. But that's that might be pretty excessive. You cannot to estimate how long does it takes for a particle to do one of these cycles. 321 00:30:45,230 --> 00:30:48,740 And that is called the gyro frequency, which is problematic field facilities. 322 00:30:49,100 --> 00:30:56,509 So what you need is to make sure that the length of your plasma, the cyclical plasma this large compared to the radius on that, 323 00:30:56,510 --> 00:31:00,170 you don't have any frequencies that can interact with to get a frequency. And then in principle. 324 00:31:02,300 --> 00:31:05,690 You'll be know if you can find plus one, but not quite. 325 00:31:06,380 --> 00:31:14,810 What happens is that there is not the magic pill. Some of these traits are not uniform on very small business, monolithic feel that we are consistent. 326 00:31:15,470 --> 00:31:21,590 And those actually change the motion in a particular way is very is very important and you need to account for in these systems, 327 00:31:21,770 --> 00:31:26,780 which is what we call this as an example I have here, they just drift. 328 00:31:28,640 --> 00:31:32,690 Yes. Just describe the geometry I have my dick feel like is coming out of the ball towards you. 329 00:31:33,110 --> 00:31:33,960 And then in principle, 330 00:31:34,050 --> 00:31:42,890 for particularly the magnetic field in this case and I am positive charts and then they move in this direction with your radius and roll. 331 00:31:43,160 --> 00:31:49,100 Given my ability right now, I put electric feel in the system, which is perpendicular to the mighty field. 332 00:31:49,550 --> 00:31:53,810 Okay. So what happens with motion and this is this is actually going to be the surprising thing. 333 00:31:54,880 --> 00:31:58,270 You start here in motion and you put a target in the electric field. 334 00:31:58,280 --> 00:32:06,020 Just popped up when the particle was here. Then as you go up, the electric field is doing work on the particle and then you're getting in it. 335 00:32:06,740 --> 00:32:11,560 That means that you have a velocity that is bigger, like expect you to be on it, 336 00:32:11,690 --> 00:32:16,670 but obviously you have coming to higher velocity means in terms of of forces, 337 00:32:16,910 --> 00:32:18,080 if you want to think about it that way, 338 00:32:18,200 --> 00:32:24,979 more a difficult force or that you need more than three but very which are two which means then that for the same force the mind. 339 00:32:24,980 --> 00:32:29,720 If you have intent, you actually need to have a bigger radius of direction. 340 00:32:30,140 --> 00:32:34,760 And what you get is something like that, which I tell you. I mean, this would happen with every scientific field. 341 00:32:35,300 --> 00:32:44,090 We don't have such a strong electric field in the system. Now, when you come down here, you would actually start to work against the electric field. 342 00:32:44,540 --> 00:32:47,720 You are looking at it when you lose energy, right? 343 00:32:48,080 --> 00:32:58,120 That means that you are actually getting less difficult force and you get that you you can actually get bigger. 344 00:32:58,590 --> 00:33:05,600 It's more of a reinterpretation. And when you do one cycle, you end up this place, which is back to where you were. 345 00:33:06,900 --> 00:33:10,080 The important thing of this is not the size. This is completely exaggerated. 346 00:33:10,590 --> 00:33:14,160 Right. Usually we don't have that big displacement. What is important is that each segment. 347 00:33:15,760 --> 00:33:21,070 You continuously as you go on and on and on, you get something like that. 348 00:33:22,480 --> 00:33:31,510 So you stop it somewhere. You want to go find this particle and unavoidably this particle population, you break the great symmetry that it made. 349 00:33:31,510 --> 00:33:35,680 It goes on itself and they just signally move away. These will be culprits. 350 00:33:35,860 --> 00:33:41,080 And in particular this one is because we drift on. 351 00:33:41,170 --> 00:33:43,360 This is basically what we do in mathematics. 352 00:33:43,750 --> 00:33:53,290 We actually study how these these drifts, these velocities interact with the with the automatic fields and decide how the mighty things work. 353 00:33:53,770 --> 00:33:56,350 I want you to notice this is an interesting piece of physics. 354 00:33:56,740 --> 00:34:03,730 We kind of went back 24 billion mechanics in that the velocity is proportional to the force, not acceleration is proportional to the force. 355 00:34:04,300 --> 00:34:11,490 And with a little twist in that, you actually move your particle perpendicular to the force, not actually parallel to it. 356 00:34:11,710 --> 00:34:15,220 Right. So things are a little bit different. 357 00:34:15,760 --> 00:34:23,620 Now, how do we treat this? Theoretically, what you do is you actually do it to a scale expansion in time scales. 358 00:34:23,800 --> 00:34:28,510 What you have here is actually two scales, the one of the motion, which is very fast, 359 00:34:28,510 --> 00:34:34,360 and you have the pay scale of the fields in the background that that that are basically get in the street. 360 00:34:34,720 --> 00:34:41,170 Right. So what you do is you you define to normalise times one normalise to the general 361 00:34:41,170 --> 00:34:44,889 frequency across time scale and the other one normalise to another frequency, 362 00:34:44,890 --> 00:34:48,280 which is the one of the, of the mind fields. 363 00:34:48,820 --> 00:34:53,410 Then the particle position depends some time through those two not normalised variables. 364 00:34:53,830 --> 00:35:02,380 Right. And what you can do is separate the motion into the slow motion of the centre of a simple plus, a superior motion that is really fast. 365 00:35:03,160 --> 00:35:05,110 Right. And then you have corrections. 366 00:35:05,110 --> 00:35:11,740 I mean, once you begin to include more and more tension, it is not circular, is elliptical well, not political, is somewhat triangular. 367 00:35:11,950 --> 00:35:15,960 And you keep correcting and correcting incorrect and you can get the circular motion out of this. 368 00:35:17,170 --> 00:35:20,590 This was proposed. I mean, that was scale expansion. 369 00:35:21,010 --> 00:35:29,980 Classical already did it in the sixties. Peter Cato is is actually the person that proposed the easiest way of of of doing this system. 370 00:35:30,160 --> 00:35:31,480 And it actually works quite well. 371 00:35:31,690 --> 00:35:41,019 What you can do then is that once you look at the system, right, you can actually obtain equations for this low dependence of these things. 372 00:35:41,020 --> 00:35:46,630 This is the position of the centre of the city. Paul And this here is the reading of the simple right. 373 00:35:46,960 --> 00:35:52,900 So you can see how slowly the centre of this pragmatically line because there is no force along it. 374 00:35:52,900 --> 00:35:56,800 So you can, you can move it along on it drifts slowly across. 375 00:35:57,400 --> 00:36:04,630 You can actually see how the circle as it goes around it becomes larger or smaller as we're moving the particle around. 376 00:36:04,900 --> 00:36:09,850 Aren't that part of the velocity actually can be affected by electric fields and all that I know it affects. 377 00:36:11,080 --> 00:36:17,620 The final thing that you get is that you are moving around rings of stars, right? 378 00:36:18,010 --> 00:36:22,510 With these three simple out of the velocities and then you get up again a hit equation 379 00:36:22,510 --> 00:36:26,530 in which you actually the characteristics of it are the most of the particles. 380 00:36:27,400 --> 00:36:33,130 And you get things like these. This is a might if you like. I think what you have is that you have a ring of charts. 381 00:36:33,370 --> 00:36:38,920 That move moves mostly parallel to the Magic V line, but they slowly can drift across. 382 00:36:40,240 --> 00:36:49,180 And you have to finish. This is not only a nice expansion into scale of and stuff like that, it's actually extremely crucial to our machines. 383 00:36:50,140 --> 00:36:54,250 We have to take into account these three because otherwise they wouldn't work on. 384 00:36:54,250 --> 00:37:04,209 I have here two samples. The first one is the Tokamak, which is a isometric between configuration, which looks like a doughnut and what you have. 385 00:37:04,210 --> 00:37:12,390 A magic film produced by the Royal Magnets, which is a magic filler, goes along the long length of the of the light. 386 00:37:12,730 --> 00:37:19,690 In principle, you would think that that's enough. But it turns out because of the separately so that a small parallel is right, they never stop. 387 00:37:20,350 --> 00:37:26,530 You actually need to have an almighty feed such that this in the short direction of the doughnut so 388 00:37:26,530 --> 00:37:33,579 that the composition of it looks like that it's kind of lying along along it to keep the particle seen, 389 00:37:33,580 --> 00:37:39,370 to avoid that from killing you, that actually requires a cover into the system. 390 00:37:39,910 --> 00:37:45,760 I won't go into details of that, but that is expensive and that is actually can be dangerous for instabilities and stuff like that. 391 00:37:45,760 --> 00:37:52,719 So there were some people that thought that what the the current you want to create a system of magnets 392 00:37:52,720 --> 00:37:57,910 that easily form in such a way that you get the same effect as you couldn't pick them up from the current. 393 00:37:59,290 --> 00:38:04,239 These are very smart idea so that you can prove that you kind of work in electric motor device. 394 00:38:04,240 --> 00:38:12,430 That's why these these devices have these we are shapes. It turns out that if you forget about the drifting systems, they don't work at all. 395 00:38:12,970 --> 00:38:18,760 And it's being the case that. Until probably the end of the age of the nineties. 396 00:38:18,760 --> 00:38:22,660 People were designing these things, not pursuing their dreams. None of them work well. 397 00:38:23,140 --> 00:38:26,200 As soon as you can prove them for this, they were fantastic. 398 00:38:26,530 --> 00:38:29,590 Well, not as good as that one, but it's getting close. 399 00:38:30,190 --> 00:38:33,700 So that's it for me for now. If you have any questions.