Analytical approach to thermal destabilization of high-pressure glow discharge

Thermal mechanism of plasma contraction has been considered. The model consisting of the coupled balance equations for electron density and gas temperature is treated asymptotically for large Damkohler number. Analysis shows influence of Joule heat release on transverse inhomogeneity of the high pressure glow discharge. Basic results are demonstrated here by explicit analytical expressions for the electron density and temperature profiles. The voltage-current characteristic with positive slope indicates two distinct branches: lower current branch corresponds to the normal glow mode and upper current branch is related to the contractive mode. The conditions favoring the transition of the diffusive mode of positive column to the contractive one are considered.