Transit-Time RF Heating of Plasma Based on Fermi Acceleration

Abstract

A theoretical study is made of the plasma heating by a coherent rf field localized in a plasma. This heating method is based on Fermi stochastic acceleration; the transit time acceleration occurs randomly when the rf period is much less than the time between two successive entries of the charged particles into the localized field. The initial heating rate is provided analytically, and the optimum design for the heating experiment is suggested. The time evolution of the velocity distribution function is demonstrated by numerical calculations. The bulk heating rather than the tail heating occurs for parameters which gives the best heating rate. The temperature exhibits an essentially linear time dependence, in contrast to the square time dependence predicted by Akhiezer and Bakai.