Filamentation of the plasma channel in a high-pressure microwave discharge

An analytical model of the filamentation of a thin plasma channel in a high-pressure microwave discharge is proposed. The problem of the scattering of a plane electromagnetic wave by a thin plasma channel (the channel width is much less than the skin depth) with radially and azimuthally nonuniform plasma density is solved. The dependence of the electric field amplitude in the channel on the channel radius is found. Simple relations allowing the evaluation of the channel parameters are derived. A deformation of the initially axisymmetrical channel is traced up to the stage in which an ionization-recombination quasi-balance is established. The relation between the main discharge parameters and the direction along which the channel filamentation occurs is obtained. The results obtained are compared with the available experimental data