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General Fusion plans to use an imploding shockwave of molten lead to compress a magnetized plasma "spheromak" target in order to make it burn more efficiently.

How come the lead does not quench the plasma (it better not, otherwise thats 50 million down the drain)? Does the lead compress the plasma via confining the plasma's magnetic field (something that a non-metal liquid would not be able to do), while avoiding direct contact? If not, and mechanical contact is necessary, how come it doesn't immediately rob heat away from the minuscule amount of plasma?

A related question, which is not about the liquid-plasma interaction but instead concerns the liquid flow:

Help with Modeling a Liquid Vortex. (Related to General Fusion)

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Kevin Kostlan
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  • Hmmm... sounds like General Fusion fails the mainstream physics criterion on this site by a long, long shot? – CuriousOne Oct 18 '14 at 02:57
  • General fusion should have mainstream, sound physics given the large investment in it. If it "fails" that would probably be due to engineering shortcommings and/or competition from a natural fusion reactor (cheap solar PV). The physics is the easy part, it should have been worked out by not. – Kevin Kostlan Oct 18 '14 at 03:40
  • What "large investment" are we talking about? ITER alone is estimated to cost $20billion,and I wouldn't be surprised to learn that the total investment in fusion,to date,has reached over100 billion if we adjust it for inflation and calculate a reasonable NPV. Not that any of that matters to physics. I do agree that PV is the economically far better bet. Even the products of mainstream fusion research will not be able to compete with cheap energy from the sun. – CuriousOne Oct 18 '14 at 04:48
  • That's interesting… I think in Rhodes' book on the making of the atomic bomb, he said America spent somewhere around three billion dollars on the Manhattan Project (when adjusted to current dollar amounts that is ~$25 billion). Mind you that was all within a few years time while all fusion funding started in the 1970's (give or take 5 years). So I think America has spent significantly less per year on fusion than fission… though I am not arguing for or against it. – honeste_vivere Oct 28 '14 at 23:08

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Eddy currents.

Conductors resist changes in magnetic field. This is the basis of the magnet-in-copper-pipe demo.

When the conductive metal encroaches on the plasma ball it encounters the ball's (spheromak's) magnetic field. The eddy current effect pushes back on the metal and pushes inward on the plasma, compressing and adiabatically heating it. The plasma's charged particles both generate and are confined by their magnetic field, so no direct physical contact is necessary.

Even if the eddy currents work hard enough, other challenges such as the timing precisions, getting the vortex to collapse smoothly, and manipulating the extremly hot metal still loom but don't necessary ruin the feasibility.

Their approach is by no means certain, but it is worth a try given it's novelty, grounding in sound physical principles, and potential impact.

Kevin Kostlan
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