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Artistically shaped magnets may make stellarators easier to manage than ITER
- dmix 9y agoI was just reading about stellarators in the book "A Piece of the Sun" [1] about the history of fusion. I find it fascinating (and a bit worrying) they are still basically attempting to optimize the same two approaches that were developed in the 50s/60s, tokamak and stellarator. I respect the scientists who continue to work on this. Many people have spent their whole careers on it and have died without making significant progress. It's inherently challenging because it's super expensive and working at super high temperatures. But the potential of the end goal might be enough to keep people working on it perpetually. [1] https://www.amazon.com/gp/aw/d/1468304933/ https://www.amazon.com/gp/aw/d/1468304933/
- dom0 9y agoFusion is simple — practically primitive — whereas plasma physics is insanely-mind-numbingly difficult. To sustain a fusion process, plasma physics have to be tamed. That's the hard part. The Wendelstein 7-X, which the article is about, can't even do fusion, it's entirely about plasma physics.
- msie 9y agoThe old guard has to die off before a new approach can be tried.
- colordrops 9y agoWhat are the new approaches being ignored or staved off by the old guard?
- benpbenp 9y ago> But the potential of the end goal might be enough to keep people working on it perpetually. Working on it perpetually, you say? If only we could somehow harness that energy...
- lovemenot 9y agoWe can in principle. But so far the energy to operate their harness matrix exceeds their work output.
- saalweachter 9y agoI am fascinated by the class of problems it is worth spending your life working on only to fail.
- lovemenot 9y agoPerhaps you could research these a little deeper ...
- Sir_Substance 9y agoThere are a bunch of other interesting ideas out there as well. There's the polywell, my personal favorite, which uses a powerful electric field to confine the fuel: https://en.wikipedia.org/wiki/Polywell https://en.wikipedia.org/wiki/Polywell (You can make a kind of shitty version of this in your garage with two microwaves, some thick wire and a healthy dose of personal risk: https://en.wikipedia.org/wiki/Fusor https://en.wikipedia.org/wiki/Fusor ) There's the Dense Plasma Focus, one version of which is being developed by Lawrenceville Plasma Physics. They're cool dudes, I once donated $10 to help them get a new Beryllium cathode about three years ago, they still send me periodic and detailed updates on their progress. You can read about their approach here, complete with radical 90's theme and pretty good video: http://lppfusion.com/fusion-power/dpf-device/ http://lppfusion.com/fusion-power/dpf-device/ Sandia National Laboratories is using a massive Marx generator [1] to power the Z-Machine, a Z-pinch that uses powerful magnetic fields generated by high current to squeeze matter in the middle of a conductor: http://www.sandia.gov/z-machine/research/fusion.html http://www.sandia.gov/z-machine/research/fusion.html This approach is known as ICF, and is also being pursued by the National Ignition Facility, who use lasers instead: https://lasers.llnl.gov/science/icf/how-icf-works https://lasers.llnl.gov/science/icf/how-icf-works So there's a few different ideas out there. However, if you really want to know why no significant progress has been made[2] you need only look at this graph: https://imgur.com/sjH5r https://imgur.com/sjH5r Note that it has a citation at the bottom, you should follow it and read the article to see that this isn't a bullshit internet chart. In the US at least, fusion has been consistently funded at a rate that the US government /knows/ is too low to see significant progress. You're welcome to make your own guesses on why this is the case. [1] My second favorite thing in HV equipment after the explosively pumped flux compression generator: https://en.wikipedia.org/wiki/Marx_generator https://en.wikipedia.org/wiki/Marx_generator https://en.wikipedia.org/wiki/Explosively_pumped_flux_compression_generator https://en.wikipedia.org/wiki/Explosively_pumped_flux_compre... [2] I'm not sure this is really the case. I think that the fusion research community has made admirable progress under trying circumstances.
- dmix 9y ago> (You can make a kind of shitty version of this in your garage with two microwaves, some thick wire and a healthy dose of personal risk: https://en.wikipedia.org/wiki/Fusor https://en.wikipedia.org/wiki/Fusor ) This reminded me of that guy who tried splitting atoms in his apartment in Sweden in 2011. Turns out last year in 2016 the police came back again because someone told them off he had Uranium. They shut down the whole neighbourhood and didn't let him come home for a full day while they searched it with a bomb squad and radiation team: https://richardsreactor.blogspot.ca/2016/04/20160401-and-again.html https://richardsreactor.blogspot.ca/2016/04/20160401-and-aga... Risky stuff to do in this age of over reaction.
- petters 9y agoBoth the article and that book compares "human fusion" to the sun. But there are surprising differences. In fact, the sun generates less energy per volume than a compost. It's all about the scaling of the surface area vs. the volume.
- AnimalMuppet 9y ago> In fact, the sun generates less energy per volume than a compost. Though the sun can keep it up far longer than a compost can... > It's all about the scaling of the surface area vs. the volume. If I understand that statement correctly, would it be easier to create a fusion reactor if we made it bigger?
- nnfy 9y ago>would it be easier to create a fusion reactor if we made it bigger? Absolutely-but only when you approach mass scales on par with small suns. So not in a practical sense. To elaborate, plasma in stellar bodies is essentially contained by gravity, as opposed to complex electroomagnetic fields that have to be painstakingly engineered and tend to be unstable.
- ajuc 9y agoWhat if we made a small black hole and put plasma in orbit?
- petters 9y agoA small black hole would probably glow very bright by itself, so it could be a useful energy source in orbit (for a while, until it crashes into Earth).
- dredmorbius 9y agoObjects in orbit don't suddenly stop being in orbit. There's no reason a black hole would de-orbit into Earth. And if it did, it would largely continue to orbit through the Earth, or what bits of it remained following passage. That said, I don't suspect the approach would be particularly viable.
- theothermkn 9y ago> I find it fascinating (and a bit worrying) they are still basically attempting to optimize the same two approaches that were developed in the 50s/60s, tokamak and stellarator. This would be a bit like worrying that aerospace engineers are still optimizing wings. Like wings, tokomaks/stellarators are the best tools for the job, as dictated by the underlying physics of the systems in question. Basically, donut-shaped magnetically-confined plasmas "leak" into themselves, rather than out into the world. > Many people have spent their whole careers on it and have died without making significant progress. This is a popular view that is entirely wrong. The figure of merit, which is the triple product of confinement time, density, and temperature, outpaced Moore's law right up until a gain of about 0.95, when the magnetic technology of the day caused the necessary size increase to put ITER in the realm of international cooperation. ITER absolutely will produce more power than it consumes. The plasma physics are just that well understood. The problem is size. MIT have recently worked out that a new breed of superconducting magnets can more than double the available field strength, resulting in a 16-fold reduction in reactor size (due to a 4th power gain in confinement strength as a function of field strength). They hope to achieve a gain of about 2 with a university-scale reactor before ITER, designed with the magnets available at the time, is complete. Most, if not all, of the above comes from https://www.youtube.com/watch?v=L0KuAx1COEk https://www.youtube.com/watch?v=L0KuAx1COEk. ARC and SPARC, the MIT reactor concepts, are the most exciting thing I've heard about in...gosh, I guess my whole life. They could pull it off. If they do, we could save the planet with fusion-powered CO2 scrubbing. We could avert disaster.
- Razengan 9y ago> Many people have spent their whole careers on it and have died without making significant progress. I wonder... if there are entire domains of technology that simply -cannot- be achieved without AI – machines building and improving themselves. We have already seen problems that simply cannot be solved within the lifetime of humans or in terrestrial environments, like telescopes in space vs. those on ground, or crossing long distances in "generation spaceships.."
- wiz21c 9y agoyou seem to mix the time it takes to bring a solution to the problem, with the invention of the solution itself. For me, AI is just another tool on top of others. You can't build an AI to, say, control a plasma without a thorough understanding of plasma physics (acquired without the use of AI)... So I'd say AI may be useful, but not in the sense that it will bring a breakthrough...
- dredmorbius 9y agoI'm not entirely sure that's the case. It's occurred to me that AI might actually represent a form of nonscientific capability. That is, the ability to achieve results but without the understanding or structured knowledge that we consider to be part of science. That's not saying that AI will solve the problem, just what the situation might be should it do so. I'm still trying to wrap my head around what it actually does itself.
- sulam 9y agoI kept waiting for the artistic magnets. Sadly the opening image the best you get.
- dom0 9y agohttps://www.google.de/search?q=wendelstein+7+x&tbm=isch https://www.google.de/search?q=wendelstein+7+x&tbm=isch https://www.google.de/search?q=wendelstein+7+x+magnete&tbm=isch https://www.google.de/search?q=wendelstein+7+x+magnete&tbm=i...
- karlshea 9y agoThere's a bunch of pictures of them in the article's slideshows.
- nitrogen 9y agoLook for videos about the reactor on YouTube. Like this one. https://youtu.be/lyqt6u5_sHA https://youtu.be/lyqt6u5_sHA Also search HN for previous articles.
- tekkk 9y agoI watched this video called "MIT's Pathway to Fusion Energy (IAP 2017) - Zach Hartwig" which I thought was interesting (and which I submitted here two days ago but went unnoticed as it's the faith of many interesting HN submissions). https://www.youtube.com/watch?v=L0KuAx1COEk https://www.youtube.com/watch?v=L0KuAx1COEk There Zach gives a quick overview (well hour long) of the current state of fusion and what its future is going to be. He didn't talk too much about stellarators but I feel I have now a better overall understanding of fusion physics thanks to him.
- astrodust 9y agoIt's like Frank Gehry designed a reactor.
- crimsonalucard 9y ago>"Let me make it very clear: fusion is, if you simply look at the carbon dioxide goals we have, fusion would be too late to bring those carbon dioxide emissions down at the rate that we need. If renewables do the job, fusion could become part of a network of dispatchable power generation units. However, if renewables don’t do the job, fusion will be too late to prevent serious damage. In that scenario, we would find ourselves in a bad situation for a period of time that extends beyond when the first fusion reactors come on line." This quote is so telling on the limits of technology. So many people think of fusion as a technological miracle that can save the world. Here we have a man telling the world that we're fucked if we just sit on our asses waiting for this miracle.
- pirocks 9y agoCouldn't you just pump co2 out of the atmosphere if you had sufficient energy/money ?
- Eerie 9y agoYou totally could pump it out, and I suspect that's what humanity will have to do, as clearly we are not going to stop pumping it in for a while...
- crimsonalucard 9y agopump it where?
- ItsDeathball 9y agoSeveral options: pump it back down the oil wells it came from, use fast-growing juvenile trees to "pump" it into house frames and libraries, use algae to "pump" it into useful plastics, or, if you have infinite money, bottle it and shoot it at Mars to thicken the atmosphere.
- rosser 9y agoSolar sails and balloons wouldn't require infinite money. Merely a lot.
- Animats 9y agoThere was a previous article on HN about the WX-7. It's an incredible piece of mechanical engineering. It's more symmetrical than it looks at first. The thing has the thermal management problem from hell. The magnet coils are superconductors and have to be maintained down near liquid helium temperatures. The plasma is at a few million degrees. These are inches apart. 3D printing might help when the next one is built. Rocket engines have some of the same problems - they're plumbing parts filled with cooling hollows. Those take way too many joints and welds to build. The Space-X Dragon spacecraft has 3D printed engines, which gets the part count down. If we ever get room temperature superconductors, these things will be much simpler. If we ever got high temperature superconductors, so that the whole thing could run hot, like a boiler, that might make it economically feasible.
- okket 9y agoThe engineering challenges and their solutions are described in detail in this video: "Wendelstein 7-X - from concept to reality" (10m30s) https://www.youtube.com/watch?v=lyqt6u5_sHA https://www.youtube.com/watch?v=lyqt6u5_sHA
- bradleyjg 9y agoIf they have to keep the temperature down near liquid helium they must be using (and need) type I superconductors. If we get room temperature superconductors any time in the near future it will almost certainly be type II.
- vilhelm_s 9y agoWhat's the difference between them? When would you need one or the other?
- bradleyjg 9y agoTurns out I was wrong. These applications use niobium-titanium or niobium-tin, both of which are type II superconductors. They do have relatively low Tc -- 10-20 kelvins versus >80 kelvin for the best HTSC, and are cooled even lower to maximize the critical field and current (i.e. maximum they can withstand before losing superconductivity).
- maxxxxx 9y agoIf you speak German, this podcast is fantastic: https://alternativlos.org/36/ https://alternativlos.org/36/. The sheer number of technological challenges in a fusion reactor is just crazy. Besides plasma physics you have to invent welding techniques, materials and a lot of other stuff. Everything is on or over the limit of what we can do now.
- Roritharr 9y agoI can also highly recommend it. My favorite tidbit were the diamond encrusted screwheads...
- someSven 9y agoYeah, I thought there was also one in English. I may confused it with one of those: http://omegataupodcast.net/tag/fusion/ http://omegataupodcast.net/tag/fusion/
- maxxxxx 9y agoThis one is good too but it's about ITER.
- 0xbear 9y agoThis is what real engineering looks like.
- erikpukinskis 9y agoI wonder if you could make it in the form of a tree, where you took the leaves and wrapped them around to join the roots, like an inside out donut. So in the middle you'd have your conjoined mega stream, and then that would flow upward, be separated out into filaments which then curl around in all directions down to the roots where they are re-merged into the megastream. Probably too much turbulence at the branches, but maybe they can use vibration and learning to find beneficial harmonics. I would hire sound engineers. I just have an intuition that a single stream will never have adequate confinement and you'll need redundancy in the geometry to get good concentration.
- bdamm 9y agoYou should build your design and tell us if it works. Or even better, patent it and maybe make millions from licensing it to a conglomerate.
- erikpukinskis 9y agoWhy would I build it? You have to model this stuff computationally before you even have a whiff of an idea whether it would work.
- alanbernstein 9y agoYou mean a tokamak?
- deleted 9y ago[deleted]