Mechanisms of microwave surface discharge propagation

A microwave discharge propagating over the surface of a dielectric antenna is studied. It is experimentally shown that the velocity of discharge propagation over the surface is maximal early in microwave pulse application and grows with the applied power. The breakdown wave defines the velocity of the discharge at its early stages (t = 1-3 mu s). Ambipolar diffusion governs the discharge propagation at the stage of its evolution (t = 3-100 mu s), and, finally, slow surface combustion is possible only at the stationary stage of the discharge (t > 100 mu s). The electric field is localized in a thin (similar to 1 mm) surface layer. High values of the reduced electric field, E/n = 100-500 Td, provide efficient energy deposition to the plasma, i.e., favor the rapid heating of the gas and the efficient generation of charged particles. This makes the discharge promising for hypersonic aerodynamics. (c) 2005 Pleiades Publishing, Inc.