Living in the future

[maradydd]

An enterprising open-source hacker who goes by the moniker Famulus, using polywell plasma confinement, has achieved desktop-scale nuclear fusion.

There are some really lovely photos of plasmas and lab equipment on the blog, and all the STL files for the polywell itself, plus Ruby source code for running the thing, are available on github. Go to.

ETA: That's fusion full stop, not "a sustained fusion reaction producing more energy than is consumed by plasma containment". I'd wager my left temporal lobe that he's running at a net energy loss. However, polywell confinement is one of the more promising technologies out there for net-gain fusion; interested parties should check out the work that EMC2 Fusion is doing.

Comments

[vanbeast.livejournal.com]

Ruby, you say? Fascinating.

[graydon.livejournal.com]

I find myself unable to differentiate fusion research projects that are quackery from fusion research projects that are simply part of a slow technological climb towards working production systems. Which is this, and why are you convinced?

[whswhs.livejournal.com]

I was wondering that myself, with a sidebar of "Is this an actual physical experiment, or are they simulating it on a computer?"

[maradydd.livejournal.com]

Cf. my reply to graydon below. I'm pretty sure this is an actual physical experiment.

[maradydd.livejournal.com]

Polywell containment has been around for a while now; the Department of Defense started funding research into it in 1983, and according to the wikipedia article I linked, in 2005 Robert Bussard's research team achieved 10⁹ fusion events per second. The Navy appears to be impressed with their results, given that they're continuing to fund the research to the tune of several million dollars a year; apparently the granting of this funding is based on peer-reviewed results, so there's that.

It looks to me like Famulus is aiming to reproduce Bussard's results with the WB-6 design, which seems like a reasonable way of going about it.

[graydon.livejournal.com]

I'm aware that fusion is an achievable state (I follow ITER progress to some extent, seemingly alone among most nerds) and did read the wikipedia page. I guess I just find myself overwhelmed any time someone starts giving the sales pitch on their uniquely-probable break-even fusion system. The LLNL thing, for example ... I dunno. I guess it's just a hazard of the territory. Energy systems are full of snake oil salesmen at every level, it's so hard to tell who's even working in good faith. Solar, fuel cells, bioethanol, all are like this; why should fusion be any different?

[heron61.livejournal.com]

My thoughts exactly. Fusion has proven to be impressively difficult (it's been 20 years away for most of my life) and so I'm seriously inclinded to doubt small-scale results like these. OTOH, if true, it's quite cool.

[maradydd.livejournal.com]

Inducing fusion events actually isn't that hard. The issue for power generation is inducing lots of fusion events, all in one place, sustained over an extended period of time, without putting in more energy than you get out. A tokamak (http://en.wikipedia.org/wiki/Tokamak), for instance, can produce sustained fusion, but all the tokamaks that have ever been built need more energy to keep their plasma at sufficient temperature than the fusion reaction produces, thus aren't suitable for power generation.

Famulus' project is probably almost certainly running at a net energy loss. That's okay, though. As I said above, it looks like he's working to reproduce results from 2005 that were declassified fairly recently. Meanwhile, the team that produced those results in the first place has funding to improve their existing designs and scale them up. The math suggests that net energy gain is feasible; it'll be exciting to see whether they can pull it off in practice. I'm cautiously optimistic.

[phanatic.livejournal.com]

We're not sure yet. Tabletop fusion is actually fairly easy; electrostatic confinement systems (Farnsworth fusors (http://en.wikipedia.org/wiki/Fusor)) are pretty easy to build. The problem is that the majority of the ions you inject into the well rapidly leave it and need to be reinjected if you ever want them to fuse. There's a significant paper (http://dspace.mit.edu/handle/1721.1/11412) from MIT that, if correct, is basically the death knell for any fusion process that isn't a) in thermal equilibrium and b) not D-T.

The Polywell is a related design, which uses a combination of electrostatic and magnetic fields to confine the ions. The big question is about the Bremmstrahlung losses; you've got electrons moving around, which means they're emitting radiation, and that means you're losing energy out of the plasma. The MIT paper says that if you're confining the plasma in this manner, you're going to lose more energy through that path than you can possibly get out of the (relatively) small number of fusion events that are occurring, so you're boned.

That said, the MIT paper might be wrong, and Bussard was a pretty clever guy. Personally, I think magnetic confinement fusion, tokamak-style, is a difficult enough problem that it will probably *never* produce commercially-viable fusion power (at best, I could see it being used in applications where you don't expect to profit, just like how RTGs are used to power space probes today), and that Polywell research is a good avenue to explore.

[(Anonymous)]

...and if I'm an old fuddy dud who doesn't want some new fangled... wait. Did you say desktop nuclear fusion?

Hrm...

Do I *have* to use ruby? I guess perl would be too dangerous.

[ndgmtlcd.livejournal.com]

What impresses me the most is that open source hackers can set up a useful vacuum chamber so easily.

[lightning-rose.livejournal.com]

Well hell, just last week I finally sold that old flux capacitor I had lying around for scrap!

[(Anonymous)]

On http://prometheusfusionperfection.com/ it sure looks like he's building a Farnsworth fusor. 2nd entry down looks like a Farnsworth style grid, to me at least.

[feonixrift.livejournal.com]

Yeah, it looked like Farnsworth to me too... I'd be much more interested in something closer to the Polywell designs; the issues with Farnsworth are well known by now.

[siliconshaman.livejournal.com]

Hmm, fusion reactors like that aren't much use for conventional power generation, but then converting nuclear reactions to heat to electrical power is rather inefficient.

However, use a polywell fusor as neutron source for a thorium reactor, then use the neutron output from that to produce a beta cascade via spallination in a betavoltaic semi-conductor stack to produce electricity..and you could have a usable power source. A solid-state fusion/fission battery.

Fusor / Polywell

[(Anonymous)]

This fusion run was using a Fusor, but we are simultaneously building a Polywell.

http://prometheusfusionperfection.com/2009/11/17/hello-internets/