CHARACTERISTICS OF THE HIGH-DENSITY PLASMA PRODUCTION BY M=0 HELICON WAVE

The characteristics of the high density plasma production by the m = 0 azimuthal mode helicon wave is investigated. By varying the power of the applied radio frequency P-rf two discharge modes exist; one is the low density mode (plasma density n(p) < 10(12) cm(-3)), at which the discharge is sustained not by a helicon wave but by the antenna induct ion field at low P-rf; the other is the high density mode (n(p) > 10(1 3) cm(-3)), in which helicon wave is excited at high P-rf; in between the two modes, n(p) jumps more than an order of magnitude. The thresho ld P-rf for the density jump is higher for the m = 0 mode than that of the m = +1 and -1 modes excited by the helical antenna. (C) 1996 Amer ican Institute of Physics.