Two-dimensional warm plasma wave field and absorption simulations for helicon plasma sources

Abstract

Summary form only given, as follows. We have modified the MAXEB computer code which was developed to model and study Inductive sources. MAXEB, a two-dimensional (r, z) simulation code, calculates the electromagnetic wave fields and power absorption in an inhomogeneous, cold, collisional plasma immersed in a nonuniform magnetic field. The current distribution of the launching antenna provides the full antenna spectra which is included in the model. We have modified the code to include warm plasma thermal effects and the contribution of collisionless (Landau damping) wave absorption by electrons. We present studies of the wave fields and electron heating profiles which include low magnetic fields (B<100 G) where the electrostatic effects of the Trivelpiece-Gould (TG) mode as well as the helicon (H) mode are important. The effect of an applied magnetic field, 2-D (r, z) density profiles and the antenna spectrum on collisional and collisionless field solutions and power absorption is investigated. It is found that at low collisionaiity /spl nu///spl omega/<0.1 and for appropriate antenna spectra that Landau damping can dominate the absorption process. Benchmark cases for which field solutions and power absorption agree with the 1-D density and magnetic field profile for the ANTENA II code are also presented. We examine cases in which the primarily electrostatic surface wave dominates the heating and is absorbed near the edge region and cases in which the primarily electromagnetic wave absorbs power in the core plasma region. The code illustrates the 2-D wave phase velocity evolution as the wave is launched from the antenna excitation region. Our helicon simulations are directly compared with selected experimental data.