PARTICLE DIFFUSION BY MAGNETIC PERTURBATIONS OF AXISYMMETRIC GEOMETRIES

The quasilinear theory of collisionless test particle diffusion in stochastic magnetic fields is extended to include the effects of finite gyroradius, particle drifts, and magnetic trapping. Runaway-electron confinement is substantially improved relative to earlier estimates which assumed that particles exactly followed field lines. Trapped particles are not expected to be stochastic. © 1979 The American Physical Society.