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

High power, pulsed microwaves are beamed forward of a model in a Mach 6 flo w using an on-board, Ku-band horn. A thin "precursor" plasma is generated j ust ahead of the bow shock in the low density free stream. Temporal and spa tial analysis of the microwave E-field and plasma conductivity in the super sonic flow field indicate that the plasma reflects a large proportion of th e microwave power in an individual pulse as soon as the plasma frequency ex ceeds the wave frequency. Possible methods for more efficient deposition of power in the free stream are discussed which could lead to increased inter action with the shock. (C) 2001 American Institute of Physics.