Fusion is a potentially unlimited source of non-carbon emitting energy. It requires the mashing together of small nuclei such as deuterium and tritium to make another nucleus and a lot of leftover energy. The problem is that nuclei do not want to be mashed together and thus to achieve fusion you need something to confine high energy nuclei for a long enough time. Currently, there are only two methods that have successfully demonstrated fusion: 1) gravitational confinement as in the center of a star, and 2) inertial confinement as in a nuclear bomb. In order to get nuclei at high enough energy to overcome the energy barrier for a fusion reaction, electrons can no longer be bound to nuclei to form atoms. A gas of quasi-neutral hot nuclei and electrons is called a plasma and has often been dubbed the fourth state of matter. Hence, the physics of fusion is mostly the physics of plasmas.
My PhD work was in plasma physics and although my thesis ultimately dealt with chaos in nonlinear partial differential equations, my early projects were tangentially related to fusion. At that time there were two approaches to attaining fusion, one was to try to do controlled inertial confinement by using massive lasers to implode a tiny pellet of fuel and the second was to use magnetic confinement in a tokamak reactor. Government sponsored research has been focused almost exclusively on these two approaches for the past forty years. There is a huge laser fusion lab at Livermore and an even bigger global project for magnetic confinement fusion in Cadarache France, called ITER. As of today, neither has proven that they will ever be viable sources of energy although there is evidence of break even where the reactors produce more energy than is put in.
However, these approaches may not ultimately be viable and there really has not been much research funding to pursue alternative strategies. This recent New York Times article reports on a set of privately funded efforts to achieve fusion backed by some big names in technology including Paul Allen, Jeff Bezos and Peter Thiel. Although there is well deserved skepticism for the success of these companies, (I’m sure my thesis advisor Abe Bers would have had some insightful things to say about them), the time may be ripe for new approaches. In an impressive talk I heard many years ago, roboticist Rodney Brooks remarked that Moore’s Law has allowed robotics to finally be widely available because you could use software to compensate for hardware. Instead of requiring cost prohibitive high precision motors, you could use cheap ones and use software to control them. The hybrid car is only possible because of the software to decide when to use the electric motor and when to use the gas engine. The same idea may also apply to fusion. Fusion is so difficult because plasmas are inherently unstable. Most of the past effort has been geared towards designing physical systems to contain them. However, I can now imagine using software instead.
Finally, government attempts have mostly focused on using a Deuterium-Tritium fusion reaction because it has the highest yield. The problem with this reaction is that it produces a neutron, which then destroys the reactor. However, there are reactions that do not produce neutrons (see here). Abe used to joke that that we could mine the moon for Helium 3 to use in a Deuterium-Helium 3 reactor. So, although we may never have viable fusion on earth, it could be a source of energy on Elon Musk’s moon base, although solar would probably be a lot cheaper.
4 thoughts on “Are we in a fusion renaissance?”
almost everyone believes in plasma physics.
see hannes alven—-he even got a noble in physics, the best version may be ‘the big bang never happened’ by eric lerner (it showed most physics theories are simply ideology—-big bang happenned because of OPEC (physics of finance, illinski, arxiv…) ; robert laughlin , another noble, may have related views.
i see current PNAS has an article on how football team wins cause wins by incumbents in political elections oct 26—not exactly their claim . (they disprove that clami published in pnas in 2010–its spurious correlations , seee http://www.replicatedtypo.com
see also h kleinart –electronic journal of theoretical physics—the ‘world crystal’ not plasma. kleinart has path integrals and quasicrystals. EJTP (el j theor phys) seems to have alot of everything that is imaginable http://www.ejtp.com
i see arxiv q-bio has an article on using a markov chain to model dna as a language. pnas also has one on dropping p value, effect size, etc in favor of something (‘a method of partitions’ http://www.arxiv.org/abs/1009.5744 there is a newer version but its lost on my computer. has A. Lo who was into showing how markets may be innefficicent, so if you throw darts at the market to pick stocks, or at the real number line to get a rational number, you may win, unlike what p samuelson or anyone else would have you believe..its a nonstationary ergodic process (dobrushin—back in the ussr)
if i played fusion music maybe i wouldnt have a 30 day notice to ‘cure or quit’ from my landlord except i i tried but didnt suceed to cure it. i do have an option—funny how that full moon works. maybe i can move a few blocks and get a bigger place for 1/3 of current rent—i put up people and they may put up wih me. (but thats the hardcore hood and i aint no hoodrat but people their treat me like a squirrel–squirrels arent involved in any drama)
I wonder if anyone still holds hope for muon-catalyzed fusion (MCF)? When muons replace electrons in hydrogen, the shielding of the nuclei is greatly reduced. In the 80’s I was optimistic that we could come up with a source of “cheap muons” (which usually boils down to “cheap pions”), but alas. Actually I was fortunate to have J.D. Jackson himself explain the issues to me.
(There’s an Australian company called Star Scientific Limited that has claimed to be “close” for quite some time.)
@David Good question. I have no idea what the state of MCF is? It looks like Star Sci still exists.
i wonder if abe bers is related to ambrose bierce (the devils’ dictionary, and incident at owl street bridge—on youtube). blacklightpower.com seems to have a nice alternative to solar. (of course a few people on arxiv tore that to shreds but who cares—he even has a few papers associated with louis debroglie people–who had some formula like lambda=h/p.). abe may also be related to abe lincoln–a name for a car.or see http://www.arxiv.org/abs/1411.7309 for another abe. see steven presse for a disagreement on this-tsallis entropy. i’m agnostic). in https://www.rt.com/op-edge/313922-cern-collider-hadron-higgs/ noted chaos theorist rossler, turned cranck, said, apart from fusion reactores destroying the reactors, cern would destroy the world. they even discussed this—ulam, etc back in the day.