Propagation and conversion of non-axisymmetric guided modes in strongly non-uniform helicon plasma

摘要

Systematic analytical and numerical studies of the 2~(nd)-order wave equations de-scribing decoupled electrostatic and helicon modes were carried out. The conversion of non-axisymmetric (m ≠ 0) helicon modes into strongly-damped electrostatic plasma modes is investigated on the basis of the general 4th-order wave equation. For steep radial density gradient, the plasma density, at which mode conversion occurs, can be considerably lower as in weakly inhomogeneous plasma. This case is studied for a plasma column with a peaked density distribution in the center.