Fokker-Planck studies of the Constance B plasma

Fokker-Planck studies of the evolution of the electron velocity distribution of the Constance B mirror-confined plasma are reported. Constance B is a minimum-B magnetic mirror with an ECRH-created plasma. The time dependent Fokker-Planck code includes a bounce-averaged, quasilinear diffusion term to describe the electron interaction with the applied rf. Two different studies were carried out. In the first study an investigation was made of the effects that the location of the gas feed has on the plasma buildup. In the second, the rf power was spatially localized in order to limit the maximum attainable electron energy, as predicted by Stallard, Matsuda, and Nevins. An investigation was then made of the subsequent time development and steady state electron distribution as the n parallel was broadened