Quasilinear theory of suprathermal ions in mirror machines in the presence of rf fluctuations

A theory of fast-ion generation in the 2XIIB mirror experiment due to a single resonant electrostatic ion cyclotron mode is presented. Assuming weak radial gradients of the magnetic induction, which appear to be consistent with experimental data, it is shown that ions with small parallel excursions can be accelerated into the 40 keV region. Allowance for a periodic temporal variation of the amplitude of the wave results in stochastic motion of those ions whose range of initial parallel excursions form a limited but significant fraction of the length of the plasma. The diffusion coefficients of this class of ions are computed in the quasilinear approximation. The corresponding diffusion times are in reasonable accord with those from the experiment