WEBVTT 1 00:00:01.860 --> 00:00:21.540 Mark Kushner: Oh, good afternoon! My name is Mark Kushner, I'm the director of MEPSI, and I welcome you to the 16th graduate symposium and our special seminar today. 2 00:00:21.730 --> 00:00:33.179 Mark Kushner: It's my pleasure to introduce Professor David Rusick, today's seminar speaker from the University of Illinois. David received his PhD in physics from Princeton University. 3 00:00:33.180 --> 00:00:45.900 Mark Kushner: After which, he remained on the staff at Princeton Plaza Physics Laboratory. Before joining the Nuclear Engineering Department at the University of Illinois at Urbana-Champaign, we have served in several, 4 00:00:45.900 --> 00:00:52.380 Mark Kushner: academic and administrative roles, and is now Emeritus Professor. Yay. 5 00:00:52.520 --> 00:01:06.950 Mark Kushner: And it's gotten better looking over the years. At UAUC, he has served as assistant dean, Associate Vice President, Faculty Fellow, and most recently as Director of the Illinois Plasma Institute. 6 00:01:06.950 --> 00:01:17.229 Mark Kushner: In addition to David's research prowess, he's also very well known for his teaching excellence, having worn virtually every teaching award possible at UIUC, 7 00:01:17.230 --> 00:01:23.469 Mark Kushner: And it has a heavily subscribed YouTube channel called Illinois Energy Prof. 8 00:01:23.650 --> 00:01:35.389 Mark Kushner: Just as an aside, David taught an Introduction to Energy course for undergraduates, in which every class session, he blew up something. 9 00:01:35.390 --> 00:01:45.949 Mark Kushner: In order to demonstrate energy. And this was one of the campus's most popular courses. They kept moving me to worse and worse buildings, though. 10 00:01:46.680 --> 00:02:00.860 Mark Kushner: So David's research areas span from fusion technology, plasma deposition, plasma etching, EUV lithography, to atmospheric pressure plasma processing. And he has been highly recognized for these works. 11 00:02:00.890 --> 00:02:09.040 Mark Kushner: He is a fellow of the American Vacuum Society, American Physical Society, American Nuclear Society, and SPIE. 12 00:02:09.240 --> 00:02:20.169 Mark Kushner: He's received the Gaudet Langler Award from AVS, the Fusion Technology Prize from IEE, and the International Award in Technology from IU Vista. 13 00:02:20.400 --> 00:02:28.519 Mark Kushner: And he has, most importantly… Yes. …the 2024 recipient of the University of Michigan Plasma Prize. 14 00:02:29.040 --> 00:02:38.709 Mark Kushner: The title of David's talk today is What Infusion Technology, Physical Vapor Deposition, and EUV lithography have in common? 15 00:02:38.860 --> 00:02:56.299 Mark Kushner: However, all of those prizes and awards pale in significance. Receiving the Lipsy mug. Oh my god, a mug! Congratulations! Thank you, thank you. 16 00:02:57.410 --> 00:02:58.420 Mark Kushner: If you don't that? 17 00:02:58.560 --> 00:02:59.660 Mark Kushner: Alright. 18 00:02:59.880 --> 00:03:00.690 Mark Kushner: Alright. 19 00:03:04.360 --> 00:03:06.090 Mark Kushner: Great, thank you. Okay. 20 00:03:06.250 --> 00:03:11.470 Mark Kushner: Well, thank you, Mark. Mark and I go way back, and hopefully way forward. 21 00:03:11.690 --> 00:03:15.009 Mark Kushner: Don't let me forget my mug. All right, 22 00:03:16.230 --> 00:03:24.390 Mark Kushner: the work I'm going to talk to you about today is not possible without all of them, and probably many more I haven't mentioned. 23 00:03:24.520 --> 00:03:29.310 Mark Kushner: Those are my current or recent grad students and postdocs. 24 00:03:29.560 --> 00:03:47.460 Mark Kushner: And I have even more, but their work isn't in this talk. And it's their abilities to do this and to work exceedingly hard and be exceedingly smart, that… that it's possible. And to the many students and postdocs here present. 25 00:03:47.460 --> 00:03:51.609 Mark Kushner: I applaud you, too, because you are the future. 26 00:03:51.910 --> 00:04:02.519 Mark Kushner: And, hopefully you can replace old fogies like Mark and I along the way, and we can be tired to a beach. Okay. Just because I'm emeritus. 27 00:04:02.520 --> 00:04:14.399 Mark Kushner: I haven't figured out how to not go to work every day, and still currently have 15 graduate students. So, on with! What do these things have in common, besides the fact that I work in them? 28 00:04:14.440 --> 00:04:17.579 Mark Kushner: Alright? And here is your answer. 29 00:04:18.510 --> 00:04:30.140 Mark Kushner: They depend on the plasma's interaction with the surface for them to either work at all, or for them to work in a manner that anyone would care about. 30 00:04:30.470 --> 00:04:44.710 Mark Kushner: And so, I'm gonna tackle all of these topics today, and give you an introduction to what we're doing, and what is so super cool about the plasma-surface interaction that's made them work. 31 00:04:45.020 --> 00:04:48.559 Mark Kushner: So the outline, I'll talk about fusion technology. 32 00:04:48.830 --> 00:04:56.609 Mark Kushner: Talk about magnetron sputtering, and then talk about extreme ultraviolet lithography. 33 00:04:57.430 --> 00:04:58.760 Mark Kushner: All right. 34 00:04:59.630 --> 00:05:03.990 Mark Kushner: So… We would like to make energy like the sun does. 35 00:05:04.310 --> 00:05:18.320 Mark Kushner: That means making nuclear fusion. But we can't use hydrogen and hydrogen, because to do that, you need an extremely large volume. Remember, the Sun is this big, and the Earth is this big. 36 00:05:19.110 --> 00:05:21.180 Mark Kushner: So, we can't use gravity. 37 00:05:21.370 --> 00:05:24.459 Mark Kushner: We have to use something else, and we have to use a different fuel. 38 00:05:24.620 --> 00:05:36.970 Mark Kushner: And the easiest fuel, as you can see from here, that you need the smallest amount of combination of density, confinement, time, and temperature is deuterium and tritium, and this is a log scale. 39 00:05:37.100 --> 00:05:43.910 Mark Kushner: So, 100 million degrees, Deuterium and tritium 40 00:05:44.130 --> 00:05:55.849 Mark Kushner: And you've got to confine it. You have to have confinement time. You have to… not physically, right, you could be a steady-state plasma, but an energy confinement time. You have to hold it together. 41 00:05:56.020 --> 00:06:03.220 Mark Kushner: And since we can't use the sun's way to do it with gravity. 42 00:06:03.350 --> 00:06:05.980 Mark Kushner: We're gonna take a hint from the sun. 43 00:06:06.100 --> 00:06:20.049 Mark Kushner: And look at the picture of this beautiful plasma flare, and do you notice that it looks like, hey, imagine this connects here in a torus, and the torus is twisted? 44 00:06:21.130 --> 00:06:24.400 Mark Kushner: That's a minimum energy state of a plasma. 45 00:06:24.700 --> 00:06:36.390 Mark Kushner: Just like a ball that would roll down a hill and would stay at the bottom of a hill, a plasma in a twisted torus is a confined, minimum energy state. 46 00:06:36.590 --> 00:06:40.869 Mark Kushner: So let's make something on Earth that looks like that. 47 00:06:41.670 --> 00:06:46.939 Mark Kushner: And by the way, The surface heat flux of the sun 48 00:06:47.090 --> 00:06:51.490 Mark Kushner: Is 64 million watts per meter squared. 49 00:06:53.210 --> 00:07:03.819 Mark Kushner: And you might imagine that if you put the sun in a can, you still have to deal with that heat flux. We'll come back to that plasma-surface interaction. 50 00:07:04.470 --> 00:07:09.000 Mark Kushner: Now, the way the world is of trying to do this… 51 00:07:10.180 --> 00:07:15.339 Mark Kushner: Is to build Eater, International Thermonuclear Experimental Reactor. 52 00:07:15.820 --> 00:07:21.219 Mark Kushner: I worked in the early 90s on the conceptual design activity. 53 00:07:21.820 --> 00:07:33.350 Mark Kushner: And so, the technology that is planned in this device is early 1990s technology. It took them a long time to agree on it. 54 00:07:33.420 --> 00:07:48.810 Mark Kushner: They took a long time to start building it, they started… they actually got a license, they actually did construction, they actually started taking it together, and then they actually started taking it apart a couple times, and then back together. 55 00:07:48.810 --> 00:07:58.039 Mark Kushner: And they don't expect startup experiments till 2034, DT to 2040. 56 00:07:58.470 --> 00:08:02.000 Mark Kushner: And I seriously have my doubts if they'll ever even do that. 57 00:08:02.110 --> 00:08:05.849 Mark Kushner: Because technology has moved on. 58 00:08:06.120 --> 00:08:09.380 Mark Kushner: Alright? There is a better way. 59 00:08:10.940 --> 00:08:15.760 Mark Kushner: Now, part of the better way is simply having better maggots. 60 00:08:15.940 --> 00:08:21.970 Mark Kushner: We can now make… those superconducting coils are designed to run at 6 Tesla. 61 00:08:22.140 --> 00:08:36.799 Mark Kushner: You can now make Rebco tape superconducting coils that are flexible at 20 Tesla. And everything in magnetic, everything in fusion goes better as magnetic fields squared. So that alone means, don't make it this big, don't use those magnets. 62 00:08:37.270 --> 00:08:43.109 Mark Kushner: But there's another thing, the thing I'm gonna tell you about, the thing I've been working on since the 63 00:08:43.220 --> 00:08:46.730 Mark Kushner: 1990s, after the conceptual design activity. 64 00:08:46.860 --> 00:08:51.239 Mark Kushner: And this is a way to improve the confinement time. 65 00:08:51.640 --> 00:08:56.530 Mark Kushner: You see, every time we make a big fusion device. 66 00:08:56.750 --> 00:09:09.310 Mark Kushner: and we make it bigger, we find that energy confinement goes down, or it doesn't scale like you expected it to. And part of this, the biggest thing, is turbulence. 67 00:09:10.100 --> 00:09:15.020 Mark Kushner: You would think everything's great, but turbulent transport ruins your day. 68 00:09:15.570 --> 00:09:34.110 Mark Kushner: And this turbulent transport is driven by temperature gradients. That makes perfect sense, just think about any type of physics. If I got hot here and cold here, there's a gradient, and that gradient has free energy, right? Because where the hot part can become cold, that energy goes somewhere. 69 00:09:34.330 --> 00:09:42.210 Mark Kushner: So, a temperature and energy gradient means you're going to be ripe for turbulence. 70 00:09:44.560 --> 00:09:45.560 Mark Kushner: Bad. 71 00:09:46.190 --> 00:09:47.470 Mark Kushner: Really bad. 72 00:09:48.510 --> 00:09:55.979 Mark Kushner: The other thing… is that in a eater-like Fusion device. 73 00:09:57.640 --> 00:10:02.919 Mark Kushner: Everything that comes from the hot part of the plasma you hope to be fusing, say the sun. 74 00:10:03.300 --> 00:10:08.969 Mark Kushner: Comes out, hydrogen atoms, hydrogen ions, and it ends up hitting a wall. 75 00:10:09.250 --> 00:10:13.690 Mark Kushner: Remember, on the Sun, it doesn't hit a wall. It just keeps going into space. 76 00:10:14.260 --> 00:10:17.550 Mark Kushner: Now, let's just think about this. It hits the wall, what happens? 77 00:10:17.980 --> 00:10:24.710 Mark Kushner: Well, the wall gets hot. Okay, fine. But, if I think about what happens to an individual hydrogen. 78 00:10:25.570 --> 00:10:31.450 Mark Kushner: If I have two hydrogens hit the wall, the wall will saturate, whatever it happens to be. 79 00:10:31.640 --> 00:10:35.009 Mark Kushner: And it will come back at a hydrogen molecule. 80 00:10:35.780 --> 00:10:39.029 Mark Kushner: At the temperature of the wall. 81 00:10:39.510 --> 00:10:40.410 Mark Kushner: Right? 82 00:10:41.380 --> 00:10:44.369 Mark Kushner: 100 million degrees in the middle of the fusion device. 83 00:10:44.750 --> 00:10:47.630 Mark Kushner: Temperature wall at the edge of the fusion device. 84 00:10:48.570 --> 00:10:56.140 Mark Kushner: of the hydrogen. So your temperature gradient is enormous inside a eater-like fusion device. 85 00:10:56.460 --> 00:11:15.769 Mark Kushner: But what this also does for you, unfortunately, is if I use a magnetic structure called a diverter, so all the plasma interaction is in one location, which you need to do, otherwise you can't run it at all, okay, you do this. Because it's cold, and a lot of power. 86 00:11:16.090 --> 00:11:17.050 Mark Kushner: the… 87 00:11:17.430 --> 00:11:36.150 Mark Kushner: Stripe, this power comes on, this lambda sub Q, the fall-off distance of the power gets smaller and smaller and smaller. And so the heat flux goes up and up, and for Eater, if they think their wall can only take 10 megawatts per meter squared. 88 00:11:36.270 --> 00:11:51.460 Mark Kushner: Right? 1 sixth the surface of the sun, but you're exhausting all the power of the sun, you have to do something. And just to give you some idea of what it looks like to be at 60 megawatts per meter squared. 89 00:11:52.580 --> 00:11:55.430 Mark Kushner: I want to start the movie. 90 00:11:57.550 --> 00:11:59.490 Mark Kushner: Which I know I can start like this. 91 00:12:03.560 --> 00:12:05.849 Mark Kushner: And not have it. Oh, there we go, okay. 92 00:12:07.280 --> 00:12:08.950 Audio shared by David Ruzic: That's an arc welder. 93 00:12:09.710 --> 00:12:13.509 Audio shared by David Ruzic: And an arc welder is about 16. 94 00:12:13.510 --> 00:12:14.100 Mark Kushner: to watch from there. 95 00:12:15.840 --> 00:12:18.730 Audio shared by David Ruzic: You need to design a material that holds. 96 00:12:18.760 --> 00:12:19.830 Mark Kushner: Quebec. 97 00:12:20.730 --> 00:12:34.299 Mark Kushner: Clearly, that tungsten rod is not, because you saw it melting and sputtering away. So, to prevent Eater's tungsten walls from looking like that welding rod. 98 00:12:34.500 --> 00:12:36.179 Mark Kushner: What do they do? 99 00:12:36.840 --> 00:12:44.160 Mark Kushner: Well, they have this much heat coming off, They are going to, 100 00:12:44.600 --> 00:13:09.569 Mark Kushner: puff in some kind of gas to the edge. They're going to, make, hang on… they're going to, never allow one of these edge-localized modes to occur by controlling the magnetic field. They're throwing small pellets of fuel at the edge to make sure it stays cool. They're going to add nitrogen or argon to the edge to power the radiator away. 101 00:13:10.080 --> 00:13:16.210 Mark Kushner: And, by the way, they can't run the device at its full capabilities, or they will melt their tungsten wall. 102 00:13:16.560 --> 00:13:17.400 Mark Kushner: Okay. 103 00:13:18.510 --> 00:13:23.220 Mark Kushner: I like to remind people that 104 00:13:24.280 --> 00:13:30.300 Mark Kushner: Eater is ridiculous, and if you want to turn Eater's concept into a power plant they call Demo. 105 00:13:30.460 --> 00:13:40.750 Mark Kushner: It is absolutely enormous, and absolutely too costly. And we compare this to what 20% of the electricity 106 00:13:40.750 --> 00:13:44.989 Mark Kushner: being made in the United States happens right now in 85% in France. 107 00:13:44.990 --> 00:14:02.180 Mark Kushner: to nuclear power. A fission plant makes 4 times the power, costs 10 times less, it lasts 50 years, we know that, we have ones that have, instead of a few months. And if you really want to make a power plant, it cannot look like a scaled-up eater. 108 00:14:02.670 --> 00:14:03.650 Mark Kushner: Alright. 109 00:14:04.220 --> 00:14:07.250 Mark Kushner: So, is there a better way? 110 00:14:08.090 --> 00:14:09.180 Mark Kushner: There is. 111 00:14:09.370 --> 00:14:13.780 Mark Kushner: And it uses flowing molten lithium. 112 00:14:15.200 --> 00:14:17.560 Mark Kushner: Alright. Why? 113 00:14:20.320 --> 00:14:22.150 Mark Kushner: You heard my son analogy. 114 00:14:22.590 --> 00:14:24.909 Mark Kushner: Cold hydrogen comes back from the edge. 115 00:14:25.240 --> 00:14:29.399 Mark Kushner: What if I have something that hydrogen never comes back? 116 00:14:29.920 --> 00:14:32.479 Mark Kushner: Every hydrogen that hits the wall sticks. 117 00:14:32.760 --> 00:14:34.910 Mark Kushner: And it doesn't saturate. 118 00:14:36.020 --> 00:14:41.159 Mark Kushner: Alright? So if I have no cold hydrogen coming from the wall, the plasma stays hot. 119 00:14:41.690 --> 00:14:46.989 Mark Kushner: In the standard case, I have a very peaked Back to Pointer. 120 00:14:47.900 --> 00:14:53.739 Mark Kushner: I have a very peaked Temperature profile, and a flat density profile. 121 00:14:54.370 --> 00:14:57.719 Mark Kushner: If, instead, I have a pumping wall. 122 00:14:57.910 --> 00:15:05.699 Mark Kushner: I have no cold hydrogen coming back, I have a flat temperature profile, and I have a peaked density profile. 123 00:15:07.080 --> 00:15:11.859 Mark Kushner: So, if I only was getting fusion from the core. 124 00:15:12.630 --> 00:15:15.489 Mark Kushner: Now, I only have to make my device 125 00:15:15.650 --> 00:15:17.989 Mark Kushner: A little bigger than the size of the core. 126 00:15:18.690 --> 00:15:20.230 Mark Kushner: Size is money. 127 00:15:20.740 --> 00:15:27.289 Mark Kushner: I can make the whole thing smaller to get the same amount of fusion. I'm way ahead in costs. 128 00:15:28.300 --> 00:15:32.670 Mark Kushner: So… The plasma that fuses 129 00:15:34.310 --> 00:15:38.790 Mark Kushner: I only need the same size circle, so I can make my whole device smaller. 130 00:15:40.000 --> 00:15:40.909 Mark Kushner: Got him? 131 00:15:41.210 --> 00:15:45.749 Mark Kushner: Also, remember those temperature gradients that drove all those instabilities? 132 00:15:45.950 --> 00:15:46.990 Mark Kushner: They're gone. 133 00:15:49.590 --> 00:15:57.079 Mark Kushner: And you might say, Well… Aren't you gonna make the heat flux worse? 134 00:15:57.500 --> 00:15:59.540 Mark Kushner: Right? Because it's hotter at the edge. 135 00:16:00.720 --> 00:16:06.569 Mark Kushner: I think I'll come to it in here, but remember that lambda Q, that width of the heat flux? 136 00:16:06.810 --> 00:16:09.710 Mark Kushner: It scales with the Larmore radius. 137 00:16:09.820 --> 00:16:12.569 Mark Kushner: Which squares as the square root of the temperature. 138 00:16:13.050 --> 00:16:16.069 Mark Kushner: If I have a 10K EV edge. 139 00:16:16.260 --> 00:16:21.900 Mark Kushner: instead of a 1EV edge, I get the square root of 10,000, 140 00:16:22.050 --> 00:16:27.000 Mark Kushner: Which is 300 times larger stripe. 141 00:16:28.570 --> 00:16:33.809 Mark Kushner: do 300 factors there, I can handle that heat flux, no problem. 142 00:16:34.030 --> 00:16:41.039 Mark Kushner: So, furthermore, Everything bad in a fusion device 143 00:16:41.160 --> 00:16:45.020 Mark Kushner: Goes bad as the atomic number squared. 144 00:16:46.070 --> 00:16:47.690 Mark Kushner: And, 145 00:16:47.890 --> 00:16:55.250 Mark Kushner: I always tease the people that plan to use tungsten, and I say, you know, you are going to use molten metals. 146 00:16:55.710 --> 00:17:11.159 Mark Kushner: Whether you want to or not, because something's gonna burp in the plasma. Your control will not be perfect. And when it does, you have to replace your entire wall. Also, another field, you can make a fuzz. 147 00:17:11.410 --> 00:17:16.209 Mark Kushner: If I make it out of lithium, I can have quite a bit more. 148 00:17:16.490 --> 00:17:31.910 Mark Kushner: In fact, this graph shows you both for fuel dilution and radiation. I can absorb a lot of things at Z equals 3. I can only have extremely small amounts at Z equals 74. 149 00:17:32.480 --> 00:17:40.419 Mark Kushner: Here's the thing about the heat flux. Sure, the temperature is higher, but the heat flux is dramatically less. 150 00:17:41.280 --> 00:17:48.599 Mark Kushner: So… 100 times larger temperature would be, 10 times larger. 151 00:17:49.560 --> 00:17:50.740 Mark Kushner: Lambda Q. 152 00:17:51.670 --> 00:17:55.569 Mark Kushner: End result is we still can only have 10 megawatts on the wall. 153 00:17:56.900 --> 00:18:05.480 Mark Kushner: All of these things you can put together, and we've done this in a paper, that gives us about one-third of the cost of electricity. 154 00:18:08.060 --> 00:18:12.900 Mark Kushner: Alright, so… Can it possibly be true? 155 00:18:13.570 --> 00:18:23.259 Mark Kushner: If I have molten lithium on the wall, let's say I just have lithium on the wall, does it really actually do all these wonderful things I just told you about? 156 00:18:24.730 --> 00:18:44.630 Mark Kushner: All right, there's an experiment at Princeton, the lithium tokamak experiment. Relatively small, it has totally lithium walls, and its temperature profile, which normally is peaked in the center if you run it without the lithium, it is flat. 157 00:18:45.590 --> 00:18:55.939 Mark Kushner: they had an earlier machine, CDXU, and they put a molten lithium diverter into it, and its confinement time went up some factor of 3. 158 00:18:56.740 --> 00:18:58.539 Mark Kushner: Now, these are small machines. 159 00:19:02.460 --> 00:19:09.820 Mark Kushner: The biggest tokamak built in the U.S. was built in the 80s, operated in the 90s, called TFTR. 160 00:19:10.380 --> 00:19:19.189 Mark Kushner: At Princeton Plasma Physics Lab, on the very last week of operation, they let the crazy people put some molten lithium in it. 161 00:19:20.060 --> 00:19:37.800 Mark Kushner: And that week of shots are… were the record shots in terms of triple product and confinement time, which you can see the confinement time here, and the total number of the triple product of density, temperature, and confinement time. 162 00:19:38.070 --> 00:19:41.520 Mark Kushner: By having some molten lithium in the device. 163 00:19:43.630 --> 00:19:53.700 Mark Kushner: The thing is that all these things are either pulsed small experiments, or, you know, again, a one-time thing, and we're gonna stick lithium in for an instant. 164 00:19:54.340 --> 00:19:58.660 Mark Kushner: Can you actually do a real solution? 165 00:19:59.230 --> 00:20:03.359 Mark Kushner: Which means I need a continuously clean lithium. 166 00:20:04.130 --> 00:20:09.580 Mark Kushner: Clean lithium works with one shot, then it gets saturated, and again, every hydrogen that hits it, something comes back. 167 00:20:09.810 --> 00:20:14.480 Mark Kushner: So I need flowing molten lithium. 168 00:20:15.640 --> 00:20:21.399 Mark Kushner: How do I get it steady state? How do I get a clean, non-saturated surface that will pump? 169 00:20:21.550 --> 00:20:26.209 Mark Kushner: How can I pump helium, and how can I still make electricity? 170 00:20:26.630 --> 00:20:31.769 Mark Kushner: And the answer is liquid, molten lithium technology. 171 00:20:32.740 --> 00:20:34.330 Mark Kushner: Still have questions? 172 00:20:34.930 --> 00:20:41.340 Mark Kushner: all of these, and I've had a research program in the last 20 years to answer them all. 173 00:20:43.910 --> 00:20:48.710 Mark Kushner: The key is this thing, which is so… Cool. 174 00:20:49.610 --> 00:20:52.029 Mark Kushner: I use the Sabeck effect. 175 00:20:52.130 --> 00:20:53.769 Mark Kushner: I'm saying, say what? 176 00:20:54.320 --> 00:20:59.059 Mark Kushner: So… Thermocouples. Thermocouples work, because you have two different metals. 177 00:20:59.560 --> 00:21:06.159 Mark Kushner: And they're at one temperature, and that makes a voltage difference between the two metals. That's how every thermocouple works. 178 00:21:07.370 --> 00:21:12.559 Mark Kushner: So imagine one of my metals, Stainless steel, could be tungsten. 179 00:21:12.880 --> 00:21:15.499 Mark Kushner: The other one is lithium. 180 00:21:16.580 --> 00:21:24.590 Mark Kushner: And if I take one cooling channel, like this one here, right, one of these little trenches. 181 00:21:25.670 --> 00:21:33.460 Mark Kushner: The temperature at this point, remember, this inside is lithium, this side is the metal, this is the little trench. 182 00:21:33.910 --> 00:21:35.490 Mark Kushner: This is hot. 183 00:21:35.810 --> 00:21:41.809 Mark Kushner: This is cooler, because I have cooling channels in the middle of this, and the plasma's hitting the top. 184 00:21:42.070 --> 00:21:44.399 Mark Kushner: So I have a temperature difference. 185 00:21:44.770 --> 00:21:49.709 Mark Kushner: Two different thermocouple junctions with a temperature difference have a voltage difference. 186 00:21:50.060 --> 00:21:56.650 Mark Kushner: A voltage difference in a conductor, electric conductor, means I have a current. 187 00:21:57.060 --> 00:22:08.049 Mark Kushner: So, this is a graph of the current. I have a current that goes down through the stainless steel, or down through the lithium, up through the stainless steel. I have a little current loop here. 188 00:22:08.860 --> 00:22:14.400 Mark Kushner: Now… The tokamak has this enormous magnetic field in the toroidal direction. 189 00:22:14.880 --> 00:22:17.229 Mark Kushner: And I have just made a J. 190 00:22:17.560 --> 00:22:19.560 Mark Kushner: J cross B is F. 191 00:22:19.980 --> 00:22:22.900 Mark Kushner: The lithium flows along the trash. 192 00:22:23.260 --> 00:22:26.340 Mark Kushner: If it gets hotter, it flows faster. 193 00:22:26.660 --> 00:22:29.689 Mark Kushner: Takes zero energy to make it work. 194 00:22:30.460 --> 00:22:32.010 Mark Kushner: Does this really work? 195 00:22:32.120 --> 00:22:39.010 Mark Kushner: Yes, and it turns out, lithium has a huge Sabec thermal power compared to other things, which is good. 196 00:22:39.670 --> 00:22:41.389 Mark Kushner: We had to measure that. 197 00:22:41.660 --> 00:22:50.810 Mark Kushner: Then we had to make a device. We didn't have a tokamak, but we put what looks like a diverter stripe with an electron beam onto it. 198 00:22:51.280 --> 00:22:58.500 Mark Kushner: And… Come on, movie! Come on, movie! 199 00:22:59.130 --> 00:23:01.430 Mark Kushner: Movies are important, there we go, okay. 200 00:23:02.060 --> 00:23:03.059 Mark Kushner: Look at that. 201 00:23:04.660 --> 00:23:05.930 Mark Kushner: See it flowing? 202 00:23:08.610 --> 00:23:14.720 Mark Kushner: This is where the heat stripe is, and you can see it's flowing faster in this heat stripe. 203 00:23:15.330 --> 00:23:17.739 Mark Kushner: And the lithium is flowing across the machine. 204 00:23:18.860 --> 00:23:25.550 Mark Kushner: If you, don't, put the lithium in it up enough, you melt the stainless steel. 205 00:23:26.070 --> 00:23:29.569 Mark Kushner: We had heat flux up to 15 megawatts per square meter. 206 00:23:29.750 --> 00:23:31.330 Mark Kushner: That this was able to take out. 207 00:23:33.640 --> 00:23:35.710 Mark Kushner: Or 10. Alright? 208 00:23:36.830 --> 00:23:38.000 Mark Kushner: Pretty neat. 209 00:23:38.740 --> 00:23:44.490 Mark Kushner: Now… One thing here is that when the lithium starts going. 210 00:23:45.180 --> 00:23:47.530 Mark Kushner: You notice there, the beam is turned on. 211 00:23:47.760 --> 00:23:50.050 Mark Kushner: The lithium is depressed here. 212 00:23:50.960 --> 00:24:00.949 Mark Kushner: Why? Well, pretty obvious. It's moving faster, right? Same amount of material, moving faster. And this is bad, because you could get dry out in that region. 213 00:24:01.390 --> 00:24:05.710 Mark Kushner: How do I combat dry out? I need to use lithium's surface tension. 214 00:24:06.220 --> 00:24:08.619 Mark Kushner: So, our next design… 215 00:24:08.770 --> 00:24:20.069 Mark Kushner: was to make ordered meshes. So the lithium can flow freely, but along the top, we actually have, 216 00:24:21.860 --> 00:24:23.410 Mark Kushner: we actually… 217 00:24:23.850 --> 00:24:38.420 Mark Kushner: have, surface tension holding the lithium up on the surface. And yes, we do some computer modeling, alright, to actually show what the temperature profiles and the flow profiles would look like. 218 00:24:38.800 --> 00:24:53.909 Mark Kushner: But of course, we then go and actually stick it into a device, and when we measure it, now we're getting this one up to about 7 megawatts per meter squared, and we do not get that surface depression. 219 00:24:56.310 --> 00:24:57.460 Mark Kushner: Pretty cool. 220 00:24:59.550 --> 00:25:06.969 Mark Kushner: You might say, well, don't some of this have… don't you have a diverter on the top, too? Doesn't this have to actually, work? 221 00:25:07.370 --> 00:25:08.970 Mark Kushner: Upside down. 222 00:25:09.770 --> 00:25:15.909 Audio shared by David Ruzic: Yes. Book our whole experiment, put it on gimbals, and while it was running. 223 00:25:16.670 --> 00:25:29.040 Mark Kushner: This one doesn't have a pump on, but while it's running, turn it upside down. The camera flipped with it, and the lithium kept flowing in trenches, did not come out, whether it was upside down or not upside down. 224 00:25:30.270 --> 00:25:30.930 Audio shared by David Ruzic: So… 225 00:25:30.930 --> 00:25:34.809 Mark Kushner: Gravity is irrelevant to this type of surface junction. 226 00:25:36.000 --> 00:25:38.760 Mark Kushner: Alright, so all this sounds great. 227 00:25:39.650 --> 00:25:40.940 Mark Kushner: in a lab. 228 00:25:41.380 --> 00:25:43.310 Mark Kushner: So now we're up to 2011. 229 00:25:43.500 --> 00:25:54.299 Mark Kushner: I'm going to China every year, and they have a fusion device they're about to build east, their big fusion device. And they have a smaller one called HT7 sitting there. 230 00:25:54.830 --> 00:26:01.629 Mark Kushner: And the crazy American says, hey, can I put lithium in your machine? You're gonna take it all apart anyway. 231 00:26:01.910 --> 00:26:16.410 Mark Kushner: So in the very last week of operation, notice symmetry here, the last week of operation on HT7, they let me put in, my, my flowing liquid lithium concept, 232 00:26:17.390 --> 00:26:27.319 Mark Kushner: And… We don't get it filled all the way, but when the plasma turned on, that spot 233 00:26:28.240 --> 00:26:30.110 Mark Kushner: Moved to that spot. 234 00:26:30.370 --> 00:26:51.259 Mark Kushner: Right? You can see it moved across. So, so it actually did self-propel the lithium, and even though this thing wasn't filled with lithium, believe me, a bunch of lithium fell on the outside of it, you know, it was a mess. I can see why they let us do it last. To admit. But, it did 235 00:26:51.260 --> 00:26:53.500 Mark Kushner: Improve confinement time. 236 00:26:53.920 --> 00:27:00.390 Mark Kushner: And it lowered the elms, even with just a little bit of molten lithium in there. 237 00:27:01.200 --> 00:27:06.809 Mark Kushner: So, this is enough to actually put this into East. 238 00:27:07.360 --> 00:27:22.300 Mark Kushner: the large Chinese tokamak, and this is a, it's a limiter, it's something they can move in and out to get it near the plasma. And this, made improvements across the board. 239 00:27:22.460 --> 00:27:27.029 Mark Kushner: 20% improvement in confinement time, 240 00:27:28.090 --> 00:27:34.420 Mark Kushner: For just one portion of the wall, Coated with moving molten lithium. 241 00:27:36.310 --> 00:27:37.200 Mark Kushner: Alright. 242 00:27:38.030 --> 00:27:39.570 Mark Kushner: Now we're getting serious. 243 00:27:39.920 --> 00:27:42.930 Mark Kushner: Can we do this in a design 244 00:27:43.480 --> 00:27:51.420 Mark Kushner: So that it could actually work in a fusion device. The stuff in the yeast was all self-contained. The lithium never came out. 245 00:27:51.740 --> 00:27:54.749 Mark Kushner: And remember, my lithium is grabbing up all the hydrogen. 246 00:27:55.580 --> 00:28:03.520 Mark Kushner: So, I actually have to take this out through the magnetic field, take the hydrogen out, find a way to stick the hydrogen back into the machine. 247 00:28:03.540 --> 00:28:21.369 Mark Kushner: and be able to have it really work. I need a real combined, integrated system. We worked very hard, and paid both by Tokamak Energy and the U.S. Department of Energy, to build Apollo, a lithium loop that, 248 00:28:21.540 --> 00:28:39.280 Mark Kushner: Fully integrated lithium loop, a way to continually add the lithium, flow meters, pumps, a plasma source that actually can go onto the flowing plate, a place to take out the hydrogen from the lithium, and have it completely circulate. 249 00:28:39.720 --> 00:28:43.439 Mark Kushner: And there, it looks like, in reality. 250 00:28:43.680 --> 00:28:54.340 Mark Kushner: One of the real keys was having… this is east, and you can see there are places where the lithium did not cover. 251 00:28:55.510 --> 00:28:59.960 Mark Kushner: Same thing I had in HT7, places that I did not manage to get lithium into. 252 00:29:00.310 --> 00:29:06.640 Mark Kushner: So the first step is, this is a disaster for a power plant, because you've melted that part of the diverter. 253 00:29:07.220 --> 00:29:10.189 Mark Kushner: So, could we make a distributor? 254 00:29:11.710 --> 00:29:26.479 Mark Kushner: And the answer, due to a very brilliant graduate student, Steven Stemley, is yes, you can model how to have lithium coming in in one spot, and come out evenly across a whole bunch of holes. 255 00:29:27.090 --> 00:29:34.330 Mark Kushner: It's a bunch of turning equations that you optimize, and you end up with a shape that looks like this. 256 00:29:34.760 --> 00:29:36.910 Mark Kushner: And then you actually build it. 257 00:29:37.100 --> 00:29:44.640 Mark Kushner: And you actually build it, and these are the channels when we turn it on, and you can see that all the channels fill up. 258 00:29:46.610 --> 00:29:50.299 Mark Kushner: That's just so cool. Yes, he got a PhD. All right. 259 00:29:50.400 --> 00:29:51.490 Mark Kushner: Okay. 260 00:29:51.860 --> 00:29:55.159 Mark Kushner: So now, we put this all together. 261 00:29:55.280 --> 00:30:10.920 Mark Kushner: We've got our plate there, you've got your post structure with your full channels, you've got the lithium, and is it really going to work? And this is due to another brilliant graduate student, Dan O'Day, who just got his PhD. 262 00:30:15.530 --> 00:30:18.950 Mark Kushner: And I think the movie's going. Look at that. 263 00:30:20.600 --> 00:30:24.849 Mark Kushner: It's flowing. I mean, it doesn't look like it's flowing, but it is flowing from here to there. 264 00:30:25.390 --> 00:30:28.730 Mark Kushner: Right? Let's see… get this one to go. 265 00:30:32.340 --> 00:30:33.100 Mark Kushner: Oops. 266 00:30:38.210 --> 00:30:40.520 Mark Kushner: What's the secret, you think, to getting the movies to work? 267 00:30:44.030 --> 00:30:46.280 Mark Kushner: Alright, are these movies, too? 268 00:30:49.220 --> 00:30:49.885 Mark Kushner: Oh… 269 00:30:57.990 --> 00:30:59.039 Mark Kushner: There we go. 270 00:31:00.460 --> 00:31:06.279 Mark Kushner: And the lithium covers those posts, by the way, which is important. You want the lithium to just cover everything. 271 00:31:07.220 --> 00:31:11.170 Mark Kushner: So, this, this was pretty incredible. 272 00:31:14.470 --> 00:31:20.740 Mark Kushner: Then we could run it at different powers, different speeds, and… 273 00:31:22.390 --> 00:31:24.549 Mark Kushner: You can get different flow rates. 274 00:31:24.760 --> 00:31:31.769 Mark Kushner: By putting different currents into the pumps, up to 5 times more grams per second of lithium going through. 275 00:31:31.910 --> 00:31:38.189 Mark Kushner: And it's laminar, it's stationary, and it actually really works. 276 00:31:38.770 --> 00:31:41.569 Mark Kushner: What about if you put an electron beam on it? 277 00:31:42.830 --> 00:31:51.759 Mark Kushner: Lithium didn't jump out, and the beam missed, by the way. It should not be melting the steel edge here. 278 00:31:51.870 --> 00:31:59.069 Mark Kushner: you know, experiments are messy. Alright? But, we did illustrate that it can take these heat fluxes as well. 279 00:31:59.170 --> 00:32:05.839 Mark Kushner: Which is, this was only 2 megawatts per meter squared, only because half our electron beam is 280 00:32:06.040 --> 00:32:11.610 Mark Kushner: Not going where it's supposed to, but still, it's a very impressive result. 281 00:32:11.840 --> 00:32:30.250 Mark Kushner: We tried to put a plasma source on, that electron beam, through an ECR plasma. We can do this, and then this shows how much hydrogen can go into it, because you've got to do that. And then, of course, you need to take the hydrogen out, which we showed we can also do with a distillation column. 282 00:32:32.120 --> 00:32:33.460 Mark Kushner: The next step. 283 00:32:34.610 --> 00:32:38.519 Mark Kushner: TRL5 is to put this into our Stellarator. 284 00:32:38.830 --> 00:32:48.629 Mark Kushner: If you're old enough, you might remember there was a Vega Stellar raider at Greisfeld in Germany. That's been at Illinois since 2017. We call it Hydra. 285 00:32:49.730 --> 00:33:08.670 Mark Kushner: hybrid Illinois device for research and applications. And, as a stellar rater, can be continuously on, and so we are going to put this flowing molten lithium loop in an actual relevant environment of a stellar rater. 286 00:33:08.880 --> 00:33:10.370 Mark Kushner: And see what happens. 287 00:33:10.730 --> 00:33:15.559 Mark Kushner: Because the next step is to put it into a 288 00:33:16.290 --> 00:33:25.890 Mark Kushner: pretty good mid-size, superconducting 20 Tesla Fusion device, like ST40, with its field upgrades. 289 00:33:26.020 --> 00:33:37.969 Mark Kushner: So we're working closely with Tokamak Energy, and we hope after the Hydra tests, this is the next test, because this could lead to commercial fusion. 290 00:33:38.680 --> 00:33:40.270 Mark Kushner: I think… 291 00:33:40.390 --> 00:33:47.479 Mark Kushner: that Spark will demonstrate that a tokamak can do cube equals 1, and unlike what was done at Livermore. 292 00:33:48.200 --> 00:33:56.239 Mark Kushner: That was energy in compared to energy out, but remember, the energy that went into making those lasers was 100 times more electricity. 293 00:33:56.620 --> 00:34:05.349 Mark Kushner: Real engineering Q equals 1 is what we could do with magnetic fusion, because your energy… continual energy input is very low. 294 00:34:07.280 --> 00:34:12.830 Mark Kushner: So, that's what were done in fusion, all based on these plasma-material interactions. 295 00:34:13.690 --> 00:34:14.909 Mark Kushner: Next subject. 296 00:34:16.380 --> 00:34:17.939 Mark Kushner: Magnetron sputtering. 297 00:34:19.440 --> 00:34:22.049 Mark Kushner: This is a coating of a nuclear fuel rod. 298 00:34:22.460 --> 00:34:24.130 Mark Kushner: Made with our device. 299 00:34:25.190 --> 00:34:28.099 Mark Kushner: This is a porous layer. 300 00:34:28.380 --> 00:34:35.659 Mark Kushner: Such that if the zirconium in the fuel rod fails, the radioactive gases get trapped in this layer. 301 00:34:35.900 --> 00:34:43.589 Mark Kushner: On top is a fully dense, amorphous, zirconium carbide grated with zirconium, zirconium carbide. 302 00:34:44.489 --> 00:34:54.770 Mark Kushner: All of that, the porous coating and those top non-porous coatings, were done in one machine by simply changing the input on the power supply. 303 00:34:55.190 --> 00:34:58.110 Mark Kushner: As opposed to moving it from place to place to place. 304 00:34:58.980 --> 00:35:08.250 Mark Kushner: This is just one of the amazing, cool applications that can be done with the impulse power supply. 305 00:35:09.020 --> 00:35:15.600 Mark Kushner: Basically, this is magnetron sputtering with cathode reversal. 306 00:35:17.500 --> 00:35:22.540 Mark Kushner: So… I'm backing up a bit, because I gotta show you the cool stuff first. 307 00:35:22.790 --> 00:35:26.630 Mark Kushner: But, to do sputtering. 308 00:35:27.190 --> 00:35:37.820 Mark Kushner: You ram ions into a metal target. It doesn't have to be metal, whatever you want to make. Say, zirconium. You ram it into zirconium, zirconium atoms come out. 309 00:35:38.330 --> 00:35:42.199 Mark Kushner: If you make the plasma super dense. 310 00:35:42.480 --> 00:35:45.790 Mark Kushner: You actually can ionize some of those atoms coming out. 311 00:35:45.990 --> 00:35:49.429 Mark Kushner: And that's high impulse magnetron sputtering. 312 00:35:49.820 --> 00:35:57.140 Mark Kushner: Where magnets come in, the magnets hold the electrons very near the target. That traps and generates the ions. 313 00:35:58.370 --> 00:36:04.810 Mark Kushner: Our idea, well, my idea, was to change the pulse at the end and make it positive. 314 00:36:05.470 --> 00:36:07.529 Mark Kushner: And we can control that amount. 315 00:36:07.960 --> 00:36:13.429 Mark Kushner: And that turns out to be able to do an incredible number of things. 316 00:36:14.250 --> 00:36:20.970 Mark Kushner: So, normally, this… Pointer. 317 00:36:22.330 --> 00:36:35.180 Mark Kushner: Normally, right, when the magnetron's operating, here there's a magnet back here, so these are the magnetic field lines, this is the trapped plasma, it makes ions here, and initially, the potential is negative. 318 00:36:35.520 --> 00:36:39.909 Mark Kushner: And it goes up to, say, zero, or a little above zero. Plasma potential. 319 00:36:40.460 --> 00:36:42.750 Mark Kushner: Alright? And the ions fall this way. 320 00:36:43.940 --> 00:36:49.810 Mark Kushner: When I immediately reverse this potential, I make a hall thruster. 321 00:36:49.980 --> 00:36:58.330 Mark Kushner: Do you know what a Hall thruster is for electric propulsion? That's exactly a Hall thruster. So all of my ions get accelerated out, that were there. 322 00:36:58.920 --> 00:37:03.049 Mark Kushner: But what is so cool, we get plasma expelled. 323 00:37:03.320 --> 00:37:07.460 Mark Kushner: The Plasma potential is raised to a specific value we set. 324 00:37:07.850 --> 00:37:13.759 Mark Kushner: But, that potential goes everywhere. The plasma potential goes across. 325 00:37:14.380 --> 00:37:27.200 Mark Kushner: So, this electric field region moves all the way across. I now have a potential drop at my substrate, so the ions reaching my substrate hit the substrate at a controlled energy. 326 00:37:27.430 --> 00:37:46.129 Mark Kushner: I want 42 EV, I put 42 EV on the kick. Oh, no, no, I want to be below the sputtering threshold. I want 15 EV, or 10, or maybe I want the implant ions, I want 200 EV or 400 EV. I get to choose, and I can go from step to step every millisecond later with a different waveform. 327 00:37:46.530 --> 00:37:54.190 Mark Kushner: In addition, because I'm raising the potential, that's an electric field sending electrons back to the… 328 00:37:54.530 --> 00:38:06.379 Mark Kushner: back to the target, and that means I have energetic electrons, which will now ionize the gas, or the neutral sputtered atoms, that are en route to the substrate. 329 00:38:07.210 --> 00:38:12.519 Mark Kushner: So, this concept can do a lot of cool stuff. 330 00:38:12.780 --> 00:38:15.079 Mark Kushner: We get a higher degree of ionization. 331 00:38:15.850 --> 00:38:24.679 Mark Kushner: We can control the energy reaching without having to bias the substrate, and that means you can do it on glass, you can do it on an insulator. 332 00:38:26.160 --> 00:38:36.439 Mark Kushner: And we can actually control the ratio of target ions to gas ions by adjusting the lengths of the sizes of the pulse. 333 00:38:37.750 --> 00:38:38.750 Mark Kushner: No. 334 00:38:39.420 --> 00:38:41.070 Mark Kushner: This is cool. 335 00:38:41.280 --> 00:38:44.929 Mark Kushner: But we've done a lot of work to understand what happens. 336 00:38:45.240 --> 00:38:54.590 Mark Kushner: So, the first paper that we published on this was there. We actually, submitted a device patent, which we got. 337 00:38:55.450 --> 00:39:00.820 Mark Kushner: But more importantly, just this year, we got a method patent. 338 00:39:01.370 --> 00:39:07.789 Mark Kushner: So… If you're not familiar with patents, a device patent is, this is exactly what we built. 339 00:39:08.000 --> 00:39:09.830 Mark Kushner: And nobody else. 340 00:39:10.000 --> 00:39:15.709 Mark Kushner: It's gonna be able to build exactly what you built, but they can change a couple components, and they get around your device path. 341 00:39:15.950 --> 00:39:24.759 Mark Kushner: A method patent that says, okay, it's a magnetron, and what we do is we reverse its potential, and it does these things. 342 00:39:25.670 --> 00:39:33.549 Mark Kushner: Doesn't matter how you do it, if you reverse the potential and you do these, it's now covered by this method pattern. And this is a really big deal. 343 00:39:36.190 --> 00:39:40.729 Mark Kushner: We wrote a paper about the ion energy distributions. 344 00:39:40.930 --> 00:39:49.329 Mark Kushner: We showed that if you put, you know, 100 volts on, you get 100 volt ions, but not only that, you get more plasma. 345 00:39:49.550 --> 00:39:59.910 Mark Kushner: Otherwise, this would decrease, but instead, because you have that plasma potential sweeping across, you ionize more material. 346 00:40:01.970 --> 00:40:08.389 Mark Kushner: A way to look at this, as our diagnostics have gotten more sophisticated, time is here. 347 00:40:08.760 --> 00:40:11.769 Mark Kushner: This magnitude is up, and this is energy. 348 00:40:11.880 --> 00:40:28.059 Mark Kushner: So normal magnetron sputtering, you get a few energetic ions coming out. You turn on the kick, this is your Hall thruster, early kick portion, then this is the stuff falling through the plasma potential, set exactly to the potential you want. 349 00:40:32.560 --> 00:40:39.369 Mark Kushner: We wanted to look at the electron energy distribution. I wanted to understand the transmutation of this potential across the 350 00:40:39.950 --> 00:40:42.859 Mark Kushner: So, we measured that. 351 00:40:43.640 --> 00:41:03.249 Mark Kushner: And the, colored data is our, actually, electron energy distributions, time resolved at different points, and you can compare it to a M. Maxwellian, a Druvistine, or what fit best was actually using Bolsig, to do a Boltzmann solver 352 00:41:03.400 --> 00:41:06.359 Mark Kushner: With, partial waves. 353 00:41:06.950 --> 00:41:09.900 Mark Kushner: And you can predict the electron energy distribution. 354 00:41:10.550 --> 00:41:20.079 Mark Kushner: A way to visualize this electron energy distribution is, here's the electron energy, this is time, this is when the kick starts. 355 00:41:20.270 --> 00:41:23.430 Mark Kushner: And you see that there's no yellow here. 356 00:41:24.990 --> 00:41:35.730 Mark Kushner: And we believe that is those fast electrons that are doing the ionizations. And remember the referee saying, are you sure that's just not a blip on your, you know, oscilloscope or something? 357 00:41:36.100 --> 00:41:41.830 Mark Kushner: And then we showed them that this happens every time, no matter what we ground, no matter what we do. 358 00:41:42.040 --> 00:42:01.220 Mark Kushner: this is actually the transit of those higher… of that higher potential. It's not an individual electron moving, right? It's a… all of a sudden, there's an acceleration, well, actually, there's an acceleration all across. So we published that, but then we, just… this just came out, it did come out in September of this year. 359 00:42:02.920 --> 00:42:20.199 Mark Kushner: We did it as a function of space. So we moved our probe as a function of space. We get a Maxwellian during the pulse, a Druvistine knot, and something subdruvistine, during the positive pulse. We have very detailed measurements of the electron energy. 360 00:42:20.200 --> 00:42:28.760 Mark Kushner: And what we actually see is the potential… it doesn't have a little cliff that runs across, but rather it moves up. 361 00:42:29.050 --> 00:42:33.719 Mark Kushner: But that still means there's an electric field almost everywhere at one portion. 362 00:42:33.910 --> 00:42:36.380 Mark Kushner: That does this ionization. 363 00:42:38.470 --> 00:42:48.189 Mark Kushner: We've added more diagnostics. Now we have a PSM that gives us both energy resolution and species resolution. 364 00:42:48.900 --> 00:42:52.120 Mark Kushner: And we discovered something really interesting. 365 00:42:52.900 --> 00:43:03.559 Mark Kushner: That if we look straight down at the target, or up at the target, perpendicular to the target, we see one ratio of, that's the on-axis. 366 00:43:03.950 --> 00:43:07.650 Mark Kushner: Okay? On axis of the direction the things are coming, right? 367 00:43:07.760 --> 00:43:11.480 Mark Kushner: Of, say, the metal, the target to argon. 368 00:43:11.770 --> 00:43:17.720 Mark Kushner: But if we look perpendicular, You know, so here's the magnetron, and we're looking sideways. 369 00:43:18.040 --> 00:43:22.019 Mark Kushner: We get a very different ratio of the metal to the argon. 370 00:43:23.230 --> 00:43:25.300 Mark Kushner: How? Why? 371 00:43:26.220 --> 00:43:29.550 Mark Kushner: Well, first, it's very real. 372 00:43:29.860 --> 00:43:33.930 Mark Kushner: Shoot. And I didn't include the slide on why. 373 00:43:34.770 --> 00:43:36.429 Mark Kushner: Okay, I'll tell you why. 374 00:43:37.470 --> 00:43:42.289 Mark Kushner: If you look in time-resolve photography at high PIMS things, there's these spokes that move around. 375 00:43:42.750 --> 00:43:52.360 Mark Kushner: And there is an asymuthal electric field. And so, as part of this Hall effect, it accelerates ions out perpendicular. 376 00:43:52.550 --> 00:43:54.340 Mark Kushner: Why does this matter? 377 00:43:55.650 --> 00:44:00.390 Mark Kushner: You don't have to have your target parallel to your substrate. 378 00:44:00.900 --> 00:44:03.300 Mark Kushner: Pick an angle for your target to be. 379 00:44:03.970 --> 00:44:13.220 Mark Kushner: Now, I can choose to have ions that come like this, maybe to sputter off the field, the extra stuff you don't want if you're filling up a trench. 380 00:44:13.620 --> 00:44:16.480 Mark Kushner: But I turn on my potential, and everything comes straight down. 381 00:44:17.390 --> 00:44:23.919 Mark Kushner: With one device, I can get two different directionalities from two different ways to run it. 382 00:44:25.690 --> 00:44:30.280 Mark Kushner: And then the last thing on high PIMS, I'll get to UV. 383 00:44:31.130 --> 00:44:37.300 Mark Kushner: Is that most people stand… keep their same old magnets they have in their device. 384 00:44:37.770 --> 00:44:40.539 Mark Kushner: And… they put a different power supply on it. 385 00:44:41.650 --> 00:44:45.059 Mark Kushner: But why not optimize the magnets? 386 00:44:45.610 --> 00:44:47.490 Mark Kushner: to make high PIMS work better. 387 00:44:47.900 --> 00:44:50.880 Mark Kushner: Which we did, and we patented. 388 00:44:51.200 --> 00:44:55.379 Mark Kushner: And… the… we… this was the tri-pack. 389 00:44:55.820 --> 00:44:59.559 Mark Kushner: We don't want everything running straight back. 390 00:45:00.410 --> 00:45:03.510 Mark Kushner: We want some of it to… more of it to escape. 391 00:45:04.060 --> 00:45:06.800 Mark Kushner: And when we do that, we get a higher ion fraction. 392 00:45:08.200 --> 00:45:11.309 Mark Kushner: We even did this in a linear pack to do it. 393 00:45:11.580 --> 00:45:15.039 Mark Kushner: And I remember submitting this paper to the journal. 394 00:45:15.150 --> 00:45:25.129 Mark Kushner: And you… normally, people complain about high PIMs, because in a conventional magnet pack, which is the black compared to the red. 395 00:45:25.360 --> 00:45:27.750 Mark Kushner: Hi PIMS always has less deposition. 396 00:45:28.320 --> 00:45:30.230 Mark Kushner: Because all the ions are going in a circle. 397 00:45:32.090 --> 00:45:47.839 Mark Kushner: With our magnet pack, we get higher deposition than standard magnetrons. And again, the referee said, I think you mislabeled your graph. No one has ever demonstrated that high PIMs can make more deposition rate than regular magnetrons. 398 00:45:48.000 --> 00:45:55.450 Mark Kushner: We said that's actually the whole point of the paper. We have not mislabeled the graphs, right? Here's more and more and more evidence. 399 00:45:55.570 --> 00:45:57.000 Mark Kushner: So that was pretty cool. 400 00:45:58.020 --> 00:46:11.770 Mark Kushner: And where you might normally get 5%, 2% ion fractions, we are able to get 35% ion fractions. Ions you can control. Ions, you can control the energy. Ions can go straight down the trash. 401 00:46:12.080 --> 00:46:13.189 Mark Kushner: Or a VIA. 402 00:46:14.060 --> 00:46:16.390 Mark Kushner: You want ions, and we can get them. 403 00:46:19.730 --> 00:46:23.149 Mark Kushner: We can utilize those magnets. This is supposed to be a movie. 404 00:46:29.390 --> 00:46:32.159 Audio shared by David Ruzic: That movie didn't work, but this one is. 405 00:46:32.160 --> 00:46:49.599 Mark Kushner: We actually now have a system where we can actually, inside the vacuum system, rotate the magnetron. Not that that would happen during a deposition, perhaps, but maybe it could, but it allows us to be able to study all of the angles in more detail. 406 00:46:49.740 --> 00:46:57.460 Mark Kushner: So we're doing this with the support of Tokyo Electron in the hopes of making a PVD tool that they will sell. 407 00:46:59.270 --> 00:47:02.060 Mark Kushner: I gotta show you some of the applications. 408 00:47:02.620 --> 00:47:19.349 Mark Kushner: Because this is actually the thing that I'm the most proud of. I can't… I'm not allowed to tell you what company, but I did look them up, and they now have a 42% market share of all the hard disks in the world. 409 00:47:19.690 --> 00:47:25.989 Mark Kushner: They're made in Singapore and Malaysia, and each of those factories has 200 of our devices in it. 410 00:47:26.540 --> 00:47:34.860 Mark Kushner: And it's really satisfying when an invention you made is actually used. And I realize there's a lot of steps in making a hard disk. 411 00:47:35.080 --> 00:47:37.820 Mark Kushner: But, the amorphous carbon layer… 412 00:47:38.440 --> 00:47:56.770 Mark Kushner: The diamond-like carbon layer that has to be extremely smooth, right? Because the magnetron head, the magnetometer head that floats across, you have a tiny, tiny gap, and you have to have precision in your fields, right? We get 80% sp3, 80% diamond amorphous carbon. 413 00:47:56.810 --> 00:48:04.890 Mark Kushner: With less than one angstrom roughness, in 150 nanometer thickness. Over… 414 00:48:05.010 --> 00:48:09.570 Mark Kushner: Over macroscopic distances. Over a 10 centimeter distance. 415 00:48:09.750 --> 00:48:13.049 Mark Kushner: I mean, that is smooth, folks, okay? 416 00:48:13.270 --> 00:48:18.309 Mark Kushner: And and it's being used. They're buying power supplies. 417 00:48:18.420 --> 00:48:19.440 Mark Kushner: Love it. 418 00:48:20.070 --> 00:48:22.650 Mark Kushner: Alright, what else can you do that's cool? 419 00:48:24.650 --> 00:48:27.719 Mark Kushner: Andre Anders, friend of mine, brilliant guy. 420 00:48:28.870 --> 00:48:32.449 Mark Kushner: This is the zone diagram, the Thornton zone diagram. 421 00:48:32.650 --> 00:48:36.570 Mark Kushner: And it shows that if you have different temperatures on your substrate. 422 00:48:36.690 --> 00:48:39.420 Mark Kushner: And it used to be pressure, but it's really energy. 423 00:48:39.670 --> 00:48:41.990 Mark Kushner: You can get different regions. 424 00:48:42.440 --> 00:48:50.220 Mark Kushner: We control this energy with the voltage of our positive kick, And we control this axis. 425 00:48:50.720 --> 00:48:53.490 Mark Kushner: With the maximum current. 426 00:48:53.980 --> 00:48:57.930 Mark Kushner: Now, we're not changing the temperature of the entire material. 427 00:48:58.110 --> 00:49:01.749 Mark Kushner: We can deposit on plastic, for heaven's sakes, right? 428 00:49:02.760 --> 00:49:06.440 Mark Kushner: What we're changing is effectively the surface mobility. 429 00:49:06.710 --> 00:49:10.549 Mark Kushner: Because of the energy that's coming down with the ions that first hit. 430 00:49:11.010 --> 00:49:18.500 Mark Kushner: So, we can actually navigate anywhere in this diagram, including the etching area. 431 00:49:18.800 --> 00:49:23.159 Mark Kushner: Alright? And that means we can remove surface oxides. 432 00:49:23.390 --> 00:49:24.560 Mark Kushner: So… 433 00:49:24.600 --> 00:49:45.220 Mark Kushner: In one device, just changing the controls. We can clean off the oils and dirts, right? We can etch back an area, we can amorphize something, we can implant to get perfect adhesion, then we can start building up, whatever control of film you want, and even put in barriers and layers to this. 434 00:49:45.420 --> 00:49:49.830 Mark Kushner: We can do this on plastic, 435 00:49:50.340 --> 00:50:10.080 Mark Kushner: which doesn't come off, no matter how you stretch it, and peel it, right? We did a 12 micron… 13 micron coating inside of bellows, and the people that did this bellows, they took it, they plunged it into liquid nitrogen, they pulled it out, they went like this, expecting, bing, bing, bing, bing, all the copper to fly off. It did not fly off. 436 00:50:11.800 --> 00:50:13.999 Mark Kushner: All right. Finally! 437 00:50:14.350 --> 00:50:15.460 Mark Kushner: 10 minutes. 438 00:50:15.980 --> 00:50:17.810 Mark Kushner: EUV electrography. 439 00:50:19.580 --> 00:50:21.870 Mark Kushner: You want to make smaller chips. 440 00:50:22.390 --> 00:50:28.210 Mark Kushner: The whole world depends on Moore's Law continuing, making more transistors per unit area. 441 00:50:28.720 --> 00:50:33.579 Mark Kushner: But the wavelength of light was stuck at 193 nanometers. 442 00:50:34.110 --> 00:50:36.410 Mark Kushner: Until 2019. 443 00:50:36.760 --> 00:50:51.969 Mark Kushner: Been working on this since way back here, but it hit high-volume manufacturing in 2019, light at 13 nanometers, allowing the sizes of features to once again be near the wavelength of light. 444 00:50:52.640 --> 00:50:57.459 Mark Kushner: This is important because we are here 445 00:50:57.770 --> 00:51:05.690 Mark Kushner: Going from the 3 nanometer node to the 2 to the 1.4 nanometer node. 446 00:51:06.250 --> 00:51:16.440 Mark Kushner: And here's something you might not recognize. When you hear 3 nanometer node, you think that means every feature is 3 nanometers. It's not. 447 00:51:16.760 --> 00:51:21.280 Mark Kushner: Smallest features are still… 20 nanometers. 448 00:51:21.750 --> 00:51:24.260 Mark Kushner: Why do they call it the 3 nanometer node? 449 00:51:24.520 --> 00:51:28.350 Mark Kushner: Because the density of 450 00:51:28.980 --> 00:51:36.089 Mark Kushner: Transistors per unit area is as if there was one layer where they're only 3 nanometers wide. 451 00:51:36.670 --> 00:51:39.050 Mark Kushner: What they've done is they've stacked them vertical. 452 00:51:39.300 --> 00:51:44.410 Mark Kushner: Or they've stacked two sets of them vertical. And that's what they keep planning to do. 453 00:51:44.550 --> 00:51:51.119 Mark Kushner: With EV lithography, we will get down to 13 nanometer wide features, and they won't go any smaller. 454 00:51:51.120 --> 00:52:11.419 Mark Kushner: Until they do double printing, but they don't have to, because you can stay on the track of Moore's Law by putting the devices vertical and having multiple devices. And so you see here, that 16 to 12, that is the actual pitch. That's the actual size of a trench or a via. 455 00:52:12.140 --> 00:52:27.050 Mark Kushner: And you can continue Moore's Law, and if you're going to continue that, which looks something like this on the devices, right, you can't do it with a laser, because you run out of power. You have to do it this way. 456 00:52:27.610 --> 00:52:35.850 Mark Kushner: You have tin droplets hit by a giant CO2 laser, At 50,000 times per second. 457 00:52:36.520 --> 00:52:45.790 Mark Kushner: And this… Makes a highly ionized tin plasma between 10 plus 8 and 10 plus 12. 458 00:52:46.110 --> 00:52:50.730 Mark Kushner: That produces 13 nanometer light. 459 00:52:51.700 --> 00:52:57.719 Mark Kushner: We no longer have any optics that are transmissive. This has to be reflective optics. 460 00:52:57.950 --> 00:53:13.140 Mark Kushner: To make the reflective optics, you need a X-ray mirror, a Bragg reflector that relies on constructive interference, meaning each bilayer has to be exactly half the wavelength that you're picking out. 461 00:53:14.490 --> 00:53:19.200 Mark Kushner: Constructing these mirrors It's an amazing enterprise. 462 00:53:20.530 --> 00:53:22.110 Mark Kushner: an expensive one. 463 00:53:22.470 --> 00:53:24.680 Mark Kushner: Done by Zeiss. 464 00:53:25.460 --> 00:53:28.690 Mark Kushner: now partially owned by ASML. 465 00:53:31.950 --> 00:53:38.419 Mark Kushner: The flatness of those layers, because the collector mirror Is literally this big. 466 00:53:39.760 --> 00:53:45.549 Mark Kushner: They said, the roughness… Is as if you took a 467 00:53:45.940 --> 00:53:50.129 Mark Kushner: Either a quarter in North America or a euro in Europe. 468 00:53:50.330 --> 00:53:52.489 Mark Kushner: And it falls flat on the ground. 469 00:53:53.250 --> 00:53:59.780 Mark Kushner: that little tiny bump of the coin flat on the ground, compared to the width of North America. 470 00:54:00.320 --> 00:54:04.029 Mark Kushner: or the width of Europe, is too rough. 471 00:54:05.400 --> 00:54:10.289 Mark Kushner: Okay? That's how flat these things are, over that incredibly large scale. 472 00:54:11.680 --> 00:54:14.689 Mark Kushner: By the way, there are 10 mirrors. 473 00:54:15.310 --> 00:54:18.240 Mark Kushner: And each mirror, at best, is 60% reflective. 474 00:54:18.510 --> 00:54:24.830 Mark Kushner: Which means you end up with maybe 1% of the light that actually gets to making the chip. 475 00:54:26.210 --> 00:54:29.779 Mark Kushner: And that also means… so there's what the machine looks like. 476 00:54:30.700 --> 00:54:36.590 Mark Kushner: If some of this tin gets on your mirror, it ruins your whole day. 477 00:54:37.650 --> 00:54:51.799 Mark Kushner: That's the reflectivity change of one mirror with one nanometer of tin. Remember, I'm putting in 30 micron droplets 50,000 times a second. 478 00:54:52.130 --> 00:54:59.590 Mark Kushner: This isn't fusion or fission, folks. The tin doesn't disappear. It gets ionized, it radiates, it's still tin. 479 00:54:59.790 --> 00:55:01.829 Mark Kushner: It goes someplace. 480 00:55:02.590 --> 00:55:07.599 Mark Kushner: This is where plasma-material interactions come into play. 481 00:55:09.870 --> 00:55:13.120 Mark Kushner: How hydrogen fixes everything. 482 00:55:15.560 --> 00:55:21.089 Mark Kushner: did experiments back in 2006 in our UV source. 483 00:55:21.760 --> 00:55:30.110 Mark Kushner: And I got the same amount of EUV in, and I measured the energy of the tin ions coming… or the xenon ions, in this case, coming out. 484 00:55:30.250 --> 00:55:39.880 Mark Kushner: Whether I added 5% hydrogen, the bottom graph, 5% nitrogen, or 100% xenon. All adjusted to get the same amount of EUV light. 485 00:55:43.500 --> 00:55:45.649 Mark Kushner: It's really cool physics. 486 00:55:46.420 --> 00:55:54.260 Mark Kushner: Which I don't have time to completely explain, but I can explain this part. I've made this warm, dense plasma that's radiated. 487 00:55:54.950 --> 00:55:56.420 Mark Kushner: It expands. 488 00:55:56.770 --> 00:56:02.240 Mark Kushner: What comes out first? There's no magnetic confinement here, it expands. Electrons come out first. 489 00:56:02.780 --> 00:56:10.320 Mark Kushner: That creates a potential, because the plasmas have to be neutral, right? This now accelerates the ions. 490 00:56:10.580 --> 00:56:18.569 Mark Kushner: So, I get 10 KeV ions, or 4 KeV ions out of this. Bad. That's really gonna destroy your mirror. 491 00:56:19.560 --> 00:56:26.990 Mark Kushner: I add in hydrogen… The hydrogen accelerates more, I might get some highly energetic hydrogen. 492 00:56:27.090 --> 00:56:36.810 Mark Kushner: But the difference between a tin or a xenon coming in at multiple KeV and a hydrogen coming in at multiple KeV is the difference between a bowling ball and a ping pong ball hitting your mirror. 493 00:56:37.390 --> 00:56:41.190 Mark Kushner: So, you can slow them down by having hydrogen. 494 00:56:41.370 --> 00:56:46.099 Mark Kushner: But most importantly, you can clean off the tin. 495 00:56:46.490 --> 00:56:49.080 Mark Kushner: If you make enough hydrogen radicals. 496 00:56:49.910 --> 00:57:00.440 Mark Kushner: Hydrogen radicals in tin on a surface make stanane, TINH4, a gas, pretty darn unstable gas. You cannot buy a bottle of stanane. 497 00:57:00.780 --> 00:57:19.010 Mark Kushner: you get a tin-coated bottle of hydrogen at twice the pressure. Okay? So, we in our lab actually have found a way… we make… we have a chemistry set, we make standing and we do experiments with it, but it is absolutely essential to making EUV lithography work. 498 00:57:19.500 --> 00:57:29.070 Mark Kushner: Because, you need, a lot of hydrogen radicals per standine removed if you have only atomic hydrogen. 499 00:57:29.170 --> 00:57:39.900 Mark Kushner: But if you have a hydrogen plasma source, that number is maybe 1,000 or 700 to 1. 500 00:57:40.340 --> 00:57:50.209 Mark Kushner: So, we've done a bunch of experiments turning the collector mirror into a plasma, that didn't work, because… 501 00:57:50.460 --> 00:57:53.860 Mark Kushner: There was too much ion energy bombardment of the mirror. 502 00:57:54.250 --> 00:58:00.219 Mark Kushner: So, we then, actually turned to surface wave plasmas. 503 00:58:00.650 --> 00:58:11.710 Mark Kushner: Surface wave plasma is the perfect plasma, because you make the plasma right where you need it, and the electron energies, and therefore the sheath drop, is very low. 504 00:58:12.480 --> 00:58:22.590 Mark Kushner: We also were able to patent this, and Starfire makes it. I've discovered… That if you do research. 505 00:58:23.090 --> 00:58:25.989 Mark Kushner: Company comes to you and says, wow, that's a great idea. 506 00:58:26.750 --> 00:58:29.250 Mark Kushner: But how can you make 100 of these? 507 00:58:30.280 --> 00:58:36.350 Mark Kushner: And as a professor, you say, well, I can't. Well, then I don't think we're going to fund you large, because what's the point? 508 00:58:36.750 --> 00:58:42.139 Mark Kushner: But if you can then point to a company made by your former postdocs, and say, they can make it. 509 00:58:42.690 --> 00:58:54.590 Mark Kushner: Oh, really? Yeah. Okay, well, let's see if you can actually make this done. And this was another case with ASML. Now, I would love to say that, 510 00:58:54.590 --> 00:59:03.530 Mark Kushner: Because, remember 1 nanometer was terrible? This etch is 95 nanometers per minute? No problem getting rid of the tin. 511 00:59:03.540 --> 00:59:10.970 Mark Kushner: I'd love to now show the next slide and say every ASML source is loaded with these things, and it's in there, but it's not. 512 00:59:11.300 --> 00:59:17.009 Mark Kushner: And this is another lesson in humility and, practicality. 513 00:59:19.240 --> 00:59:20.779 Mark Kushner: Their system works. 514 00:59:21.030 --> 00:59:24.720 Mark Kushner: They make enough hydrogen radicals with their big, giant plasma. 515 00:59:24.910 --> 00:59:32.340 Mark Kushner: They can do a few extra tricks I can't tell you about that actually make sure their mirrors stay clean. 516 00:59:33.100 --> 00:59:42.519 Mark Kushner: If it ever gets really bad, yes, they could put one of these surface wave sources in, but at least to this point, they don't have to. 517 00:59:42.690 --> 00:59:52.510 Mark Kushner: And it's also a lesson, I think, for my students, that you can be working on, you can have the perfect solution for something, and it may never, ever get commercialized. 518 00:59:52.750 --> 00:59:55.590 Mark Kushner: Because there was some other way to do the same thing cheaper. 519 00:59:56.930 --> 01:00:10.069 Mark Kushner: That's what all this stuff has in common. I got one last, slide of conclusions. Lithium-walled fusion may allow Q equals 1 in magnetic fusion this decade, and on power on the grid by 2040. 520 01:00:10.650 --> 01:00:11.720 Mark Kushner: I hope. 521 01:00:11.900 --> 01:00:12.820 Mark Kushner: May. 522 01:00:13.110 --> 01:00:21.699 Mark Kushner: HIPEMS with cathode Reversal is extending PVD to many future nodes of Moore's Law, and allows his amazing films to be produced. 523 01:00:21.890 --> 01:00:30.260 Mark Kushner: EUV lithography scanners are the most complicated machine in the world, and are economical because of the plasma surface interactions. 524 01:00:30.850 --> 01:00:32.120 Mark Kushner: Thank you very much. 525 01:00:40.640 --> 01:00:42.620 Mark Kushner: Hey, David, are there questions? 526 01:00:45.650 --> 01:00:51.280 Mark Kushner: Yes, sir? Regarding the first 15-wall, please, I have heard also proposals 527 01:00:52.010 --> 01:00:56.770 Mark Kushner: False laser deposition to solve the wall heating problem of 528 01:00:57.020 --> 01:01:06.979 Mark Kushner: How do you see… do you see that you're listening wall fusion, is that more cost-effective for large-scale generation, or how do you distinguish between these two? 529 01:01:07.170 --> 01:01:15.110 Mark Kushner: So… I think if you have molten flowing lithium on the wall, you've got all these big advantages. 530 01:01:15.220 --> 01:01:33.200 Mark Kushner: Okay? How you want to get the molten flowing lithium on the wall, right? If you want to keep, you know, hitting a solid laser target with a laser, doesn't sound the most efficient way to me. But remember, I'm looking at a toroidal device. 531 01:01:33.700 --> 01:01:50.400 Mark Kushner: Right? There are other people that say, oh no, we can do it in a linear device, or we can do it like Zap Energy with a Z-pinch, and we have… or General Fusion that is a tokamak, but it's a lithium wall that compresses and comes back out, right? I mean, so… 532 01:01:50.530 --> 01:01:53.080 Mark Kushner: low Z materials on the wall. 533 01:01:53.220 --> 01:01:56.420 Mark Kushner: is a huge advantage, and you can't get any lower than lithium. 534 01:01:56.660 --> 01:02:02.330 Mark Kushner: The fact that lithium can absorb the hydrogen gives you this new physics. 535 01:02:02.520 --> 01:02:04.330 Mark Kushner: Gives you a lot more headaches. 536 01:02:04.840 --> 01:02:14.450 Mark Kushner: I have to take that hydrogen out, which I know I can do, stick it into a pellet generator, freeze it, and throw it in in pellets into the core to keep the fueling going. 537 01:02:14.520 --> 01:02:30.370 Mark Kushner: Right? Haven't tackled that one yet. I think it's doable. There's a lot of technology transfer levels, and we're getting there, right? We're actually… when we put this into Hydra, it'll be TRL5, which is usually the valley of death of various technologies. 538 01:02:31.130 --> 01:02:32.180 Mark Kushner: So… 539 01:02:32.420 --> 01:02:42.119 Mark Kushner: I don't know if it'll be the key, or if something else will be the key, but I think Low Z coatings… renewable low Z coatings on the walls are very important. 540 01:02:43.640 --> 01:02:44.510 Mark Kushner: Yeah. 541 01:02:46.680 --> 01:02:51.039 Mark Kushner: Scalability of the lithium wall coverage. 542 01:02:51.240 --> 01:02:54.649 Mark Kushner: Well, remember, you have to cover what's called the diverter. 543 01:02:54.870 --> 01:03:06.349 Mark Kushner: It's not the entire wall. It's a stripe where the magnetic field line hits. So it's a… it's a toroidal panel, maybe 10 centimeters wide, going around 544 01:03:06.550 --> 01:03:10.189 Mark Kushner: the bottom. If the double null token macroit also has to go around the top. 545 01:03:10.600 --> 01:03:25.329 Mark Kushner: So, we're not covering every square inch with flowing lithium. Now, believe me, lithium will be everywhere, right? It evaporates, it's gonna coat everything, which I don't think is so bad, because if anything gets into the fusion device, it's only Z equals 3. 546 01:03:25.550 --> 01:03:27.529 Mark Kushner: But, 547 01:03:29.750 --> 01:03:37.979 Mark Kushner: So, from that point of view, and remember, my thing went sideways across. So if I do one panel. 548 01:03:38.200 --> 01:03:46.649 Mark Kushner: the right width, you can imagine this is all now a continuous basis, and that shouldn't change. But clearly. 549 01:03:47.270 --> 01:03:54.930 Mark Kushner: technological engineering steps to get from, you know, each step is… is large. 550 01:03:55.530 --> 01:03:59.570 Mark Kushner: But, so far, doable, if people keep working on it. 551 01:04:03.380 --> 01:04:10.700 Mark Kushner: Do you recycle most of your lithium? The lithium doesn't get used, it just goes in a circle. 552 01:04:11.430 --> 01:04:20.200 Mark Kushner: So the lithium is not, oh my god, this thing's gonna use too much lithium. No. It's the same amount of lithium. You… when you heat it up. 553 01:04:20.610 --> 01:04:22.460 Mark Kushner: Hydrogen dissolves out. 554 01:04:23.070 --> 01:04:25.649 Mark Kushner: And then the lithium just keeps going in your loop. 555 01:04:26.080 --> 01:04:31.939 Mark Kushner: Okay? Okay. And it's the same thing, like, with helium gas cooling. 556 01:04:32.060 --> 01:04:40.900 Mark Kushner: If you're gonna cool this with high-pressure helium gas, you're not throwing away the helium. It's just a heat exchange medium, and goes in a loop. 557 01:04:45.200 --> 01:04:46.099 Mark Kushner: Yes, sir. 558 01:04:51.940 --> 01:04:53.360 Mark Kushner: Extremely so. 559 01:04:56.460 --> 01:05:00.460 Mark Kushner: It must be maintaining relatively 560 01:05:00.700 --> 01:05:09.459 Mark Kushner: stringent level of, you know, cleanliness inside the chamber, because any contaminants are going to react with the liquid. Absolutely, I'll tell you. 561 01:05:09.770 --> 01:05:15.119 Mark Kushner: I didn't show the slides. We have 2 or 3 experiments designed on compatibility of materials. 562 01:05:15.570 --> 01:05:24.549 Mark Kushner: you know, if I stick something copper, like a copper gasket, in the molten lithium, it just disappears. It's crazy. So… 563 01:05:24.700 --> 01:05:26.290 Mark Kushner: stainless steel. 564 01:05:27.420 --> 01:05:37.659 Mark Kushner: predominantly compatible, although eventually the chromium stuff comes out and you're just left with pure iron. Pure iron works. Tantalum works. Tungsten works. 565 01:05:38.060 --> 01:05:45.699 Mark Kushner: And many of… we made those whole things out of, machine-printed, tantalum, or tungsten, for instance. 566 01:05:45.800 --> 01:05:50.290 Mark Kushner: So, there are some materials that are compatible with lithium. 567 01:05:50.670 --> 01:05:56.740 Mark Kushner: But, oxygen, nitrogen, carbon, all makes lithium stuff crap stuff. 568 01:05:57.150 --> 01:06:01.080 Mark Kushner: But when we flow it, all this scale that's made. 569 01:06:01.560 --> 01:06:09.680 Mark Kushner: it doesn't go around the corners, right? You can skim it off. It either sinks or floats, because it's a solid. 570 01:06:09.970 --> 01:06:20.480 Mark Kushner: So, the beauty of the liquid lithium is, just merely by flowing it through the pipe or the distributor, you clean off the crap. Now, you get too much crap, you're gonna have to worry about 571 01:06:21.020 --> 01:06:24.760 Mark Kushner: Not everything getting clogged up, which has happened to us, too. 572 01:06:24.870 --> 01:06:33.070 Mark Kushner: So, lithium is a tremendously reactive material, and that's another aspect of the technology that we're certainly trying to deal with. 573 01:06:37.850 --> 01:06:42.090 Mark Kushner: Are there any other questions? Anything on high PIMS or EUV? 574 01:06:43.420 --> 01:06:44.220 Mark Kushner: Yeah. 575 01:06:44.430 --> 01:06:50.130 Mark Kushner: B, a larger degree of ionization. 576 01:06:50.830 --> 01:06:53.530 Mark Kushner: Is that purely magnetic? 577 01:06:53.720 --> 01:07:00.779 Mark Kushner: So, so, high PIMS, forget about our cathode reversal at first, just high PIMS itself. 578 01:07:01.640 --> 01:07:06.650 Mark Kushner: It makes the plasma so dense, That the sputtered atoms 579 01:07:06.850 --> 01:07:09.640 Mark Kushner: Get ionized in that first millimeter. 580 01:07:10.100 --> 01:07:21.620 Mark Kushner: And then they turn right around. So a normal magnetron might have a current of 1 amp, this has a current of 100 amps. Because everything gets sputtered, then self-sputters, and makes a loop. 581 01:07:22.000 --> 01:07:24.240 Mark Kushner: Some of the more ions get out. 582 01:07:24.860 --> 01:07:34.220 Mark Kushner: But now, when I reverse the cathode, it's like, you know, I've pent up the racehorses. I got them all agitated and all running around cool, and I open the gate, and they come bursting up. 583 01:07:34.650 --> 01:07:50.899 Mark Kushner: Right? Plus, all the neutral atoms that were sitting there as these electrons actually rush back to the target can get ionized too, so I get more ions, and now I can control their energy by the sheath at the end of what they fall through. 584 01:07:52.430 --> 01:07:58.749 Mark Kushner: So, high PIMS in general makes more ions, but much less deposition, because everything goes in a circle. 585 01:08:01.510 --> 01:08:03.039 Mark Kushner: Anything on a UV? 586 01:08:03.840 --> 01:08:05.010 Mark Kushner: One question. 587 01:08:07.770 --> 01:08:11.110 Mark Kushner: If not, let's thank Professor Russochiadi. 588 01:08:17.310 --> 01:08:25.040 Mark Kushner: For those of you who are participating in the symposium, this would be a good time to walk over to EECS and put up your posters. 589 01:08:25.149 --> 01:08:29.190 Mark Kushner: The first poster session, will begin 590 01:08:30.180 --> 01:08:39.349 Mark Kushner: I think I hit an hour, or a little under. 591 01:08:40.340 --> 01:08:41.090 Mark Kushner: Nope. 592 01:08:42.859 --> 01:08:43.560 Mark Kushner: What?