Time for a little tokamak primer, I think. Not from me, from an actual expert.
As I stated above, but maybe you missed, magnetic pressure is a function of magnetic field strength. straight out of the NRL Plasma Formulary, which gives the result in atmospheres. Evidently nobody dares change this archaic unit that has been adopted by fusion researchers since, well, a long time.
If you are working in Teslas, 3.98 B^2 gives magnetic pressure in Atmospheres. So at 5T that works out to 98.25 atmospheres. Straight from the Plasma Formulary.
If you intend to operate at beta = 1, then by definition, plasma pressure MUST equal that. If it cannot, then you're not at beta = 1. Which appears to have been the case in ALL of RWB's work, regardless of what he thought. He was stuck at a much lower beta. But Dr. Park got to beta of about 0.7. It takes a pretty big hammer.
Tokamaks work at a much lower beta, too. Just what that beta is will depend on the particular machine and the experiment, but evidently 0.05-0.08 is considered pretty good. Magnetic fields quoted vary quite a bit as well. We've been hearing about 12 T magnets but they're not always that strong. Tokamaks dare not approach beta = 1 due to the plasma pushing against concave fields, which are unstable.
So lets look at some sources of data here. We'll start with Prof. Cowley, director at JET.http://www.psfc.mit.edu/library1/catalo ... cowley.pdf
We'll see he uses the same formula for magnetic pressure (rounds 3.98 off to 4) and puts beta on ITER at 0.08, and the axial field at 5.2T. He shows fusion power as proportional to the square of plasma pressure. If you look at slide 7, he puts magnetic pressure at 100 atmospheres, and plasma pressure at about 7 atmospheres.
Mind you, this is in a 20 keV plasma. I'd think it a stretch to just say to apply ideal gas law extrapolated to 100 million K, but obviously we're not talking about 7 atmospheres of D-T at room temperature. Cowley shows us that fusion power increases by the square of plasma pressure ... he wants all he can get.
So, yes, the magnetic pressure cited in Dr. Park's talk at 5T is correct. To get to beta = 1, by definition, plasma pressure must equal that. It can be higher than a tokamak because the convex field structure of a Polywell's cusps are stable ... they compress back like foam rubber and stiffen up as they compress, if that helps you picture it (that's my analogy for science fiction audiences).
That leaves the question of can you get to beta = 1?
Bussard did not. Park and his crew of loyal hunchbacks figured out how, or at least how to get pretty close, and they injected power on only 2 of the cusps.
Now the question is, does it scale? Can this be pushed to work on a 5T, 2 meter radius machine, and achieve net power? What intermediate steps, if any, are needed? We know Dr. Bussard would have jumped straight to full scale if allowed to. We know Dr. Park has an intermediate in mind. Neither Bussard nor Park proposed hanging electrical power generation equipment off the machine before demonstrated net power.
Now the question is, is the cost reasonable, and can funding be found? GIThruster thinks $300 million is a deal killer. My opinion is, if this were 1805, $300 million would have been a deal killer. Today, I have to ask, what technologically savvy superpower could NOT
try this? I can understand that there are a lot of capitalists out there who would rather invest in Shake Shack or Box. Me, I have a Box account, it is crap, and I would not invest in the company. And fast food is beneath my dignity as an investor.
I said it before, and I'll say it again. If I had ... OK, the number is up since my last pronouncement ... $300 million to spare, this thing would be funded already. (Ligon sadly opens wallet and sees $28).