STABILITY OF A QUASI-NEUTRAL BEAM OF NEGATIVE-IONS

The stability of a beam of negative ions propagating in the parent gas is investigated. It is shown that growth of plasma oscillations with a small growth rate is possible at subcritical currents in a quasineut ral regime. The influence of traveling secondary electrons, whose dens ity is small, is also studied. The low-frequency oscillations consider ed pose the greatest danger to a beam whose velocity is close to the v elocity of the secondary electrons. (C) 1998 American Institute of Phy sics. [S1063-7842(98)01909-6].