Ion losses induced by Alfvén ion-cyclotron instability in mirror machine with skew neutral beam injection

Abstract

The dynamic of ions in an axisymmetric mirror cell with a perturbed field is investigated. The spatial distribution of the perturbation was found in the framework of an analysis of the linear stage of the Alfvén ion cyclotron instability in a mirror trap with skew neutral beam injection. It is demonstrated that unstable perturbations do not cause losses of ions with maximal energy driving the instability. Main anomalous losses are longitudinal losses of ions with low transversal energy due to stochastic diffusion by the magnetic moment.