ELECTRON DIFFUSION IN A SPHERICAL CAVITY

Abstract

The diffusion equation for electrons in a nonuniform field is solved and the breakdown condition derived. The breakdown condition is expressed in such a manner that an effective characteristic diffusion length Λ_e is determined; the meaning of Λ_e expresses the equivalent characteristic diffusion length for uniform electric fields. From the experimental breakdown fields, in which the electric field is uniform, Λ_e is determined and used to predict theoretical breakdown curves for the nonuniform cases. Theory and experiment are compared, the agreement verifying the correctness of the approach.