Long Plasma Production by a Radio-Frequency Discharge between Dielectric-Covered Parallel Electrodes

Abstract

A very long plasma (1.5 meters) was confirmed to be produced by a radio-frequency (28 MHz) discharge between long dielectric-covered electrodes. The properties are: (1) the plasma number density drastically decreases at gas pressures below 15 Pa due to the shifting of the main discharge region toward the exterior near the electrode edges, (2) this density becomes maximum at the tip of the long electrodes and (3) becomes uniform within a narrow electrode width at intermediate pressures around 10 Pa. These properties were well explained qualitatively using the transmission line and ambipolar diffusion theories.