A THEORETICAL STUDY OF MICROWAVE HEATING IN ELMO BUMPY TORUS

Abstract

Because the plasma in ELMO Bumpy Torus (EBT) is produced and heated by microwaves, and macrostability is dependent on microwaves through the formation of the annuli, an understanding of microwave propagation and energy deposition is a crucial element in EBT theory. A central feature of the microwave heating study is the development of a ray-tracing code capable of operating with a wide variety of three-dimensional (3-D) plasma equilibrium configurations. Results are presented for plasma parameters characteristic of EBT-I and projected parameters characteristic of EBT-II. In EBT-I the extraordinary mode is very heavily damped, and the ordinary mode is weakly damped. The ordinary mode may, however, play an important role in the heating of EBT-I through mode conversion. In EBT-II the ordinary mode should be strongly damped. The code is being improved to include finite temperature effects on the ray paths and absorption at second and higher harmonic resonances.