Tri Alpha Publishes

[Rezwan]

Here it is in the Physical Review Letters – Dynamic Formation of a Hot Field Reversed Configuration with Improved Confinement by Supersonic Merging of Two Colliding High-β Compact Toroids

A hot stable field-reversed configuration (FRC) has been produced in the C-2 experiment by colliding and merging two high-β plasmoids preformed by the dynamic version of field-reversed θ-pinch technology. The merging process exhibits the highest poloidal flux amplification obtained in a magnetic confinement system (over tenfold increase). Most of the kinetic energy is converted into thermal energy with total temperature (Ti+Te) exceeding 0.5 keV. The final FRC state exhibits a record FRC lifetime with flux confinement approaching classical values. These findings should have significant implications for fusion research and the physics of magnetic reconnection.

Click on their authors tab to see who comprises the TAE team.

[Aeronaut]

Glad to see them publishing something, anything. Am I correct in understanding that they’re perfecting their containment fields?

[Brian H]

59 names. Any in particular you were noticing? Thompson?

I haven’t bought the paper, but the abstract reads kind of strangely. I guess I just basically doubt that the FRC (or anything else) is likely to produce “stable” confinement of fusion, especially pB11 fusion.

[Tulse]

Can anyone translate the paper into lay terms? Or, alternatively, what does this mean for how close Tri-Alpha might be?

[vansig]

in lay terms,
they’re blowing smoke rings at each other. or, in this case, ball lightning.

some number of years ago, their web site claimed that they could create plasma toroids at ~1 atm pressure. if i recall correctly, they were attempting to fire a pair of them towards each other inside a tube. in my opinion, they’re not anywhere as close to unity as FF is.

[jamesr]

They quote a plasma beta (the ratio of pressure over magnetic pressure) as >7 which is very good, and is a measure of how strong (ie big & expensive) a magnet you need to confine the plasma. This compares to 0.02 for some tokamaks & upto 0.5 for spherical tokamaks respectively. This is encouraging as you can confine the plasma at a much higher density in a cheaper machine.

Also, although the temperature they achieve is only 0.5keV, the electron temperature is 1/4.5 of the ion temperature, which is also promising.

After the two ‘smoke rings’ or compact toroids (CT) in their language, are fired at each other they form a ~1m wide blob of plasma with a peak density of 10^20/m^3 after around 40us, which is kept stable for around 1ms before instabilities set in, and the confinement is lost.

They say further heating mechanisms could be added such as neutral beam injectors (NBI), but I’m not sure this would maintain the favourable ion/electron temperature ratio needed for pB11 fusion

[Allan Brewer]

Thanks James, could you also explain the other publication noted by Rezwan at https://focusfusion.org/index.php/forums/viewthread/616/

[Aeronaut]

jamesr wrote: They quote a plasma beta (the ratio of pressure over magnetic pressure) as >7 which is very good, and is a measure of how strong (ie big & expensive) a magnet you need to confine the plasma. This compares to 0.02 for some tokamaks & upto 0.5 for spherical tokamaks respectively. This is encouraging as you can confine the plasma at a much higher density in a cheaper machine.

Also, although the temperature they achieve is only 0.5keV, the electron temperature is 1/4.5 of the ion temperature, which is also promising.

After the two ‘smoke rings’ or compact toroids (CT) in their language, are fired at each other they form a ~1m wide blob of plasma with a peak density of 10^20/m^3 after around 40us, which is kept stable for around 1ms before instabilities set in, and the confinement is lost.

They say further heating mechanisms could be added such as neutral beam injectors (NBI), but I’m not sure this would maintain the favourable ion/electron temperature ratio needed for pB11 fusion

So that’s a pulsed design, also? If successful, will the blob be able to generate aneutronic fusion products for the entire ~mS of stable confinement?

[Alex Pollard]

These findings should have significant implications for fusion research and the physics of magnetic reconnection.

Doesn’t magnetic reconnection stem from mistaken attempts to explain solar flares without acknowledging the electric currents that cause them?

http://www.thunderbolts.info/forum/phpBB3/viewtopic.php?f=12&t=22&start=0

Doesn’t inspire any confidence that Tri Alpha are on the right track.

[jamesr]

Alex Pollard wrote:

These findings should have significant implications for fusion research and the physics of magnetic reconnection.

Doesn’t magnetic reconnection stem from mistaken attempts to explain solar flares without acknowledging the electric currents that cause them?

http://www.thunderbolts.info/forum/phpBB3/viewtopic.php?f=12&t=22&start=0

Doesn’t inspire any confidence that Tri Alpha are on the right track.

Magnetic reconnection is key , as you say, to solar flares. But I wouldn’t say they are mistaken attempts. They have known for years simple resistive MHD models are insufficient to explain reconnection rates that fast, and that you at least need to consider the Hall term in Ohm’s law ie currents flowing across the field, and the differing resistivity parallel and perpendicular to the magnetic field.
There has been quite a bit of progress in recent years modeling for example Ellerman Bombs, and how they relate to flux emergence from the sun’s photosphere.

Here is one paper from 2002 on observations
http://iopscience.iop.org/0004-637X/575/1/506/pdf/0004-637X_575_1_506.pdf
And one from 2009 on the modeling
http://www-solar.mcs.st-and.ac.uk/~vasilis/12455.pdf

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