Plasma-resonance-assisted filament in a high-pressure microwave discharge

Self-consistent steady-state structure of a thin plasma filament maintained in atmospheric pressure argon by a rotating transverse electric field of ∼1 cm wavelength is simulated numerically under conditions when the local plasma resonance condition is satisfied at some surface inside the filament. The equilibrium radial distributions of the plasma parameters (temperature and density) and the field amplitude inside the filament are calculated based on the solution of the heat equation and the Maxwell equations. It is shown that the occurrence of strong resonant peaks of the radial component of the electric field and the power of Joule losses in the region of critical density at the periphery of the filament provide the energy deposition sufficient to achieve a relatively high gas temperature and a strongly supercritical plasma density in its central region. In relation to the values of these basic parameters of the filament and the lower limit of the external radiation power supporting it, the results obtained are in satisfactory agreement with the data of the earlier experiment.