R.A. Nebel On Plasma Calculations
In general, some types of plasma theories work pretty well and others not so well. Plasma theories work pretty well for calculating equilibria and global stability. Transport calculations and kinetic calculations are considerably more suspect. The thing that raises the red flags about the collisionality calculations is that when you look at the Chacon work he sees a big difference between square potential wells (as assumed by Nevins) and parabolic potential wells. I would not have expected that result, and that tells me that none of these results are truly "generic". I think this issue has to be resolved experimentally. That's not to imply that these calculations have no value. What they do tell you is that collisions on the boundary are beneficial (they remove angular momentum) while collisions in the core can be a problem. This, of course, was known by Bussard and Krall a long time ago. It's also possible to affect these collision rates by techniques like gas puffing into the boundary (i.e. introducing neutrals).It makes you wonder just how much could be accomplished with computers, or how little.
Also, I would like to thank M Simon, TallDave and their fellow bloggers for their continued interest in this technology. We appreciate that a great deal, but as you might imagine we have been a little too busy to communicate very much with the on-line people.