Levitated Dipole experiment

[dfryer]

Have any of you taken a look at this: http://www.psfc.mit.edu/ldx/

It's kinda tokamak-ish in the sense that it uses maxwellian heating, but I thought the idea of using a more "naturally" confined plasma (i.e. by dipole, as opposed to running current through plasma and having banks upon banks of magnets in a tokamak) to be pretty interesting. If you can find the paper on D-He3 "catalyzed" fusion using a levitating dipole reactor, I found it to be a fun (and optimistic) read - still, many hurdles to be overcome. I'd be interested in any comments or criticism, since many of you have been interested in fusion long before I even knew what it was

[Adam Szendrey]

I assume you have read more about this concept, so if you don't mind i would like to ask a few questions.
How, will they keep the superconducting ring, superconducting, while it's levitating in the vacuum? Would it bee in som sort of container ?
Though there are no stationary magnets, this dipole will need to have a magnetic field strength as high as any tokamak, if i'm correct.
Anyway, what i found most ingenius in the fusor, that it does not use Maxvellian heating, it does not consume a whole floor, and it costs very little compared to any other fusion experimental device, is lost in this LDX project.

Adam

[dfryer]

It may need fields as strong as a tokamak, but the impression that I get is that there is an inherent stability to the dipole configuration as contrasted to the tokamak situation. Currently they "charge" the ring inductively and then let it float (I believe that yes, it is surrounded by a Very Good Insulator or something along those lines). The Big Challenge (similar to preventing grid meltdown in IEC) is to build a refrigeration system that can keep the superconductor cool even in the presence of high neutron flux, which is what would really start heating it up (as far as I can tell, the plasma itself doesn't really touch the magical flying donut, so any heating would be due to fast neutrons & EM radiation)

Regarding the maxwellian heating, when I first read how IEC fusion worked, the non-maxwellianness sounded great (and I think it still does). Recently though, I ran across a paper that illustrated some thermodynamical problems sustaining a non-maxwellian distribution. If anyone knows what paper I'm thinking of, a criticism or rebuttal would be most encouraging!

As far as I understand, until we can think up a brilliant way to keep virtually all of the plasma's energy away from the grid, we won't be able to make this work in a breakthrough way. Still cool to have fusion in your basement though!

[Brian McDermott]

I actually visited the LDX laboratory a few weeks ago (see my archived MIT post in Images). They have a smaller torus magnetically suspended in the big cylindrical vacuum chamber. They were actually about to deuterium test it with supports (i.e. no levitation) in place a week after my visit.