Characteristics of a radio frequency magnetized double-ring-shaped hollow cathode plasma source with permanent magnets for high-density hydrogen plasma generation

Abstract

A rf magnetized double ring-shaped hollow cathode plasma with permanent magnets has been developed for high-density hydrogen plasma generation at various hydrogen gas pressures, pH2. The discharge breakdown voltage with magnet decreases with increasing pH2 and is lower than that without magnet at 1 ≤ pH2 ≤ 30 Pa and is otherwise higher than that. Spatial distributions of the ion saturation current density have also been investigated at various hydrogen gas pressures of pH2 = 5, 10, 20, 30 and 40 Pa. The high-density double peaks of the ion density due to the double ring-shaped hollow trenches are observed near the hollow electrode at pH2 ≥ 10 Pa. The laterally uniform high-density hydrogen plasma with a density of 1011cm−3 is attained at the distance z = 30 mm from the electrode under low gas pressure of 5 Pa and 10 Pa at rf power of 60 W.