Diffusion in electron cyclotron resonance heating magnetic mirrors

A theory of electron cyclotron resonance heating in a mirror device is applied to the radio frequency induced particle diffusion into the loss cone. It is shown that the loss time is much slower than the heating time within the stochastic heating region, but that the losses are strongly enhanced over collisional losses alone. The effects of collisions in combination with the electron cyclotron resonance heating are considered and found to give additional heating beyond the adiabatic barrier, on the time scale of the 90° collisional deflection. The collisions also act, together with the radio frequency fields, to enhance the rate of loss cone diffusion. The major assumptions and results of the theory are confirmed by exact numerical calculations. Predictions of the performance of a 25 kW electron cyclotron resonance heating experiment are made.