The thermoactivation rate of charged particles in a magnetic field

(Received 19 November 1990, revised 5 March 1991, accepted 11 March 1991)

Abstract
We consider a diffusion of a charged particle over a three-dimensional barrier in a magnetic field. By the solution of the Fokker-Planck equation it is shown that the magnetic field causes the diminishing of the pre-factor in the expression for the particle's thermoactivation rate: , . Unlike the two-dimensional case considered earlier [3, 4], in the general situation this diminishing is non-uniform with respect to the orientation of the vector B, with a saturation at some non-zero level for some range of orientations. The latter causes the splitting of the relaxation peak in the bulk materials containing randomly oriented two-well relaxators at high magnetic fields.