“…This critical current level yields a marked increase in ion-pair-production, a greatly enhanced 3914 X emission, a modification of the primary beam velocity distribution and the emission of intense RF waves. The BPD has been the subject of a continuing series of space-simulation experiments (Bernstein et al, 1978;Bernstein et al, 1980and Jost et al, 1981) One such recent work (Walker et al, 1981) has determined that the density-related plasma condition for BPD threshold +1.3 can be expressed as w = (5.8 -1.9 ) Wc, where (w ,w ) are p -1 9p…”