Simulation of transmitted current in a cylindrical cross-field diode

Summary form only given. The transmitted current in a crossed-field gap has been characterized analytically by a number of authors. One dimensional PIC simulations of a planar cross-field diode in the region near B=B/sub hull/ have been explored by Verboncoeur et al. It was shown that for monoenergetic electrons, the transmitted current shows a rapid transition when the injected current exceeds the critical current by just 1%. This transition is not observed when the injected electrons are given temperatures as small as 1/10 eV. In this study we will extend the simulation to one and two dimensional cylindrical geometries. The limiting current in the neighborhood of the Hull cut-off field for different inner/outer conductor ratios will be studied.