Microwave discharge on the surface of a dielectric antenna

A microwave discharge initiated by a surface wave on a dielectric body placed in a supersonic air flow is studied. The discharge is shown to represent a thin plasma layer that uniformly covers the antenna surface. In experiments, the discharge propagation velocity may be as high as 100 km/s, which is several orders of magnitude higher than the velocity of sound in air. The peak pulse power necessary to excite the discharge in a wide range of air pressures (from 10^?3 to 10³ Torr) is no higher than 100 kW. It is shown that the gas temperature may rise to 1000–2000 K, rapidly increasing (with a rate of ≈50 K/μs) at the early stage of discharge evolution. The discharge of this type may find applications in super-and hypersonic plasma aerodynamics (such as control of the flow near the surface of a body moving in a dense atmosphere, reduction of surface friction, optimization of ignition and combustion conditions for supersonic flows of gaseous fuel, etc.). It may also be used to advantage in development of new-generation plasma sources for micro-and nanoelectronics purposes (plasma treatment of surfaces, etching, and film deposition).