On-board projection of a microwave plasma upstream of a Mach 6 bow shock

Abstract

High power, pulsed microwaves are beamed forward of a model in a Mach 6 flow using an on-board, Ku-band horn. A thin “precursor” plasma is generated just ahead of the bow shock in the low density free stream. Temporal and spatial analysis of the microwave E-field and plasma conductivity in the supersonic flow field indicate that the plasma reflects a large proportion of the microwave power in an individual pulse as soon as the plasma frequency exceeds the wave frequency. Possible methods for more efficient deposition of power in the free stream are discussed which could lead to increased interaction with the shock.