Stellar optimization
July 22, 2017 5:22 PM   Subscribe

posted by potch at 5:37 PM on July 22, 2017 [5 favorites]

Look at the ports on that thing!
posted by Artw at 5:43 PM on July 22, 2017 [3 favorites]

Just like a man. You see a stellarator, all you can talk about is the ports. Hey, buddy. Sensors up here.
posted by Samizdata at 6:52 PM on July 22, 2017 [14 favorites]

"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."
posted by Artw at 8:05 PM on July 22, 2017 [6 favorites]

20 years away is too far...
posted by Artw at 8:05 PM on July 22, 2017 [1 favorite]

I never thought a prop could be over-greebled, but there you have it.
posted by rhizome at 9:01 PM on July 22, 2017 [7 favorites]

Man, forty years on and these guys still haven't figured out how to configure a stable transverse bi-helical plasma manifold? It's 2017. This has been a solved problem since like module 5. You can get metamaterial plasma turbine feed plates and passable oblidisks on Ali Baba for like five bucks these days. Sure, it'll explode at anything over a mEv in the presence of a housecat within a hundred meters but...

What do you mean this isn't a Volt Xoccula module forum post? That thing is real?
posted by loquacious at 9:28 PM on July 22, 2017 [3 favorites]

Now that's an everything bagel!
posted by scruss at 9:32 AM on July 23, 2017 [6 favorites]

And still the only confinement method we've been able to get working is gravitational. :(
posted by heatherlogan at 10:50 AM on July 23, 2017 [1 favorite]

At first glance, I thought it was made out of Lego bricks.
posted by ZeusHumms at 10:53 AM on July 23, 2017

That's a seriously wide encompassing "we" there, were you on the project team? :-) :-)

It certainly seems that it's a much harder problem than expected, and it seems deeply crazy that ultimately it'll use the heat generated to drive a steam engine (that drives a generator). I've had physicists look at me side eyed when I asked why there isn't a direct nuclear -> electricity conversion like some kind of hyper-solar panel. Guess that's hard but with the quixotic fusion efforts it's seem like other out there ideas could be worth chasing.
posted by sammyo at 11:58 AM on July 23, 2017

I've had physicists look at me side eyed when I asked why there isn't a direct nuclear -> electricity conversion like some kind of hyper-solar panel.

Those do exist:
Direct charging generators

In the first type, the primary generator consists of a capacitor which is charged by the current of charged particles from a radioactive layer deposited on one of the electrodes. Spacing can be either vacuum or dielectric. Negatively charged beta particles or positively charged alpha particles, positrons or fission fragments may be utilized. Although this form of nuclear-electric generator dates back to 1913, few applications have been found in the past for the extremely low currents and inconveniently high voltages provided by direct charging generators. Oscillator/transformer systems are employed to reduce the voltages, then rectifiers are used to transform the AC power back to direct current.

English physicist H.G.J. Moseley constructed the first of these. Moseley’s apparatus consisted of a glass globe silvered on the inside with a radium emitter mounted on the tip of a wire at the center. The charged particles from the radium created a flow of electricity as they moved quickly from the radium to the inside surface of the sphere. As late as 1945 the Moseley model guided other efforts to build experimental batteries generating electricity from the emissions of radioactive elements.


Main article: Betavoltaics
Betavoltaics are generators of electric current, in effect a form of battery, which use energy from a radioactive source emitting beta particles (electrons). A common source used is the hydrogen isotope, tritium. Unlike most nuclear power sources, which use nuclear radiation to generate heat, which then generates electricity (thermoelectric and thermionic sources), betavoltaics use a non-thermal conversion process, using a semiconductor p-n junction.

Betavoltaics are particularly well-suited to low-power electrical applications where long life of the energy source is needed, such as implantable medical devices or military and space applications.


Alphavoltaic power sources are devices that use a semiconductor junction to produce electrical particle from energetic alpha particles.[8][9]
posted by jamjam at 1:14 PM on July 23, 2017 [3 favorites]

"This talk [SLYT] reviews the present state of fusion energy research and .. introduce MIT's proposed pathway to use high-field superconducting magnets to achieve fusion energy at smaller unit size, at lower cost, and on a timescale relevant to climate change." (quoting the YouTube blurb)

Since ITER was spec'd the higher field strengths possible due to high-temp superconductors mean fusion can theoretically be done in a smaller and cheaper reactor now (i.e perhaps in ten to fifteen years ..)
posted by anadem at 10:14 PM on July 23, 2017

Re: Stellarator vs. Tokamak video, I was hoping for an Epic Rap Battle video and was disappointed.
posted by jrishel at 11:27 AM on July 26, 2017 [1 favorite]

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