A Tri Alpha Fusion Update

Brian Wang found through Talk Polywell a pdf file of a presentation given at the ICC/US-Japan CT Workshop in Seattle Washington on August 16, 2011.  It’s a treasure of an update on the dual pinch approach to fusion confinement, well worth a look.

Tri Alpha started as a brainchild of Professor Rostoker and for some years now has been privately funded and nearly silent on their progress.  By virtue of reputation, capitalization and organizing character Tri Alpha is a contender for a working fusion energy production mechanism.  The results reported in Seattle confirm the ideas of Professor Rostoker look valid and the engineering is getting the group closer to a fusion event.

Tri Alpha has successfully built a test machine that can form a well-confined field-reversed configuration (FRC) for holding plasma.  In simple descriptive terms the machine forms two opposed dynamic merging toroids where plasma can collide between them.

The device, named “C-2” is newly built and is the world’s largest compact toroid device.  Inside two opposed toroids with their energy directed at, or more adroitly oppositely directed move plasma a highly supersonic speed.

Each of the toroids form up an FRC at simultaneous moments and fling them together into a confinement chamber.  At the collision the energy of the plasma interact and hopefully will produce a fusion event.

The engineering of the device is paying off handsomely. To date Tri Alpha’s Hiroshi Gota reports in the pdf that the plasma hold, or diamagnetic signal achievement is a record 2 microseconds.  Not nano seconds, full microseconds.  In nuclear fusion confinement, that’s a very long time.

Gota’s slide from the pdf shows that the key to holding such a long hold is in two main areas of development.  First is active stabilization, where the external saddle coils, or magnets, work to hold the high-speed plasma in precise alignment.  Then the machine must have been built such that the electrodes could be biased, or positioned for optimization.

Gota’s second point is about conditioning the walls where the collision occurs.  It seems obvious that collisions are going to be messy things splattering about.  So the Tri Alpha team has used “gettering” to condition or coat the walls. The results – the concept functions quite well.

It looks like the machine is quite robust.  The graphs and charts in the pdf reveal that a considerable number of runs or “shots” have taken place.  The team is making good progress.

The problem suggested is that plasma shots leave behind neutrals and impurities. That’s where gettering, a kind of dissolving, evaporating and deposition of materials, is used to coat the confinement walls.  The team has to date arrived at using lithium and titanium coatings.  One wonders how many trial runs were made and this issue may explain how so much time is used.  Whether or not contamination was anticipated is unknown outside of Tri Alpha, but the solution is well on its way to a long-term design fix.

The summary result is Tri Alpha has significantly improved confinement from the original pinch idea with plasma transport rates closing in on classical values that suggest a fusion event is coming.  Important to this is the conversion rate of the speed energy into heat.  That conversion is key.  Speed with heat is what the design needs to make fusion.

The latest design looks quite different from the early art.  Professor Rostoker must be justifiably proud.  The rest of us are pleased.  One day soon we’ll see who of the Rostoker, Lerner and Bussard ideas can go commercial.  A grand day that will be.

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