Physics Commons^™

Application Of The Results Of Carbon Pellet Modeling To The Problem Of Plasma Penetration, L. L. Vahala, A. G. El Cashlan, G. A. Gerdin, P. B. Parks

Electrical & Computer Engineering Faculty Publications

The assumptions of the evaporation model for low-Z pellets interacting with magnetic fusion plasmas developed by Parks are tested. These assumptions are that the vapor density profile in the region adjacent to the pellet surface falls off with radial distance as r^-α , where 5 <α<6, and that the ionization time for the transition between charge states ז_f (i.e., for r < ~3 sonic radii). The first assumption is tested by solving a two-parameter eigenvalue problem for the evaporation cloud in the region interior to the sonic radius; the results are found to be consistent with the low-Z evaporation model. The second assumption, that ז_zi «ז_f, is tested at the sonic radius using the results from atomic physics and the low-Z evaporation model. It is found that indeed ז_zi «ז_f for plasmas with parameters close to thermonuclear conditions (e.g. CIT), but not for those of smaller Tokamaks such as …