Collisional drift instability of a weakly ionized argon plasma

Experimental and theoretical results pertaining to the collisional drift instability of a weakly ionized plasma are presented. A non-local cylindrical model is developed and solved numerically to yield dispersion characteristics which are compared with a local slab model dispersion relation. The local slab model is shown to be inadequate in describing how mode stability varies with azimuthal mode number. Detailed experimental observations of single mode coherent oscillations in a weakly ionized argon plasma are also presented. The oscillations are identified as collisional drift waves on the basis of a comparison of mode characteristics with theory. Moreover, the experimental results demonstrate that the local slab model is a poor choice for describing these non-local cylindrical experiments.