Effective Area of Microwave Discharge Interaction with EM Beam Exciting It

Abstract

In this work the research results of the electric discharge in supersonic air stream are described. The discharge is lighted in the field of linearly polarized quasi-optical electromagnetic beam of the microwave (MW) of wavelengths range, which initial level is substantially smaller than critical breakdown level. Electric breakdown is initiated by the tubular electromagnetic vibrator of resonant length placed in the MW beam. The internal hole of the vibrator is an outlet section of submerged supersonic air stream formation duct. The discharge burns in this flow and is attached to the stern end of the initiator. Measurements of spatial distribution of stagnation temperature and pressure of the stream in the wake of the discharge area have allowed to estimate energy deposition into the discharge plasma and to determine the effective area of power interaction of the discharge with the MW field exciting it. Results of experiments and their analysis have shown that this area substantially exceeds the cross section area of plasma discharge area.