Low Frequency Waves Excited in a Magnetized Electronegative Gas Positive Column

Abstract

A positive column with negative ions in a uniform longitudinal magnetic field B is analytically proved unstable in two modes of low frequency waves, i.e., the modes of ionization wave and of helical wave. The former mode is excited in B<B_c and the latter in B≥B_c, B_c being the critical field above which the plasma is helically unstable. Effects of the negative ions and of the field B on those low frequency waves are discussed on the basis of a same ratio approximation for charged particle density perturbations.