Current Distribution in Crossed-Field Accelerators. Part 3. Electrical and Gasdynamic Performance of J X B Accelerators

Abstract

Abstract : Realistic analytical description of local behavior and of overall performance of crossed-field accelerators is obtained by computing coupled two- dimensional distributions of current density, plasma properties, and fluid velocity, temperature and pressure, over the whole length of the channel. The analysis includes consideration of electron nonequilibrium, thermal and concentration diffusion, compressible turbulent boundary layers, finite reaction rates, and electron energy relaxation, and the effect of each is investigated. The development of compressible, turbulent, magnetohydrodynamic boundary layers on the electrode walls is obtained through a novel formulation that includes a transport equation for the Reynolds' stress, and a fast numerical method of solution. Analytical results obtained in this study gave consistently good agreement with experimental measurements. Applications to seeded-nitrogen and seeded-air accelerators indicate limited current fringing in the entrance and exit regions and rapid approach to periodical current density, electric field, and plasma property distributions in the main part of the channel.