Observation of ring–shaped pulsed DC discharge plasma source using single pole magnet setups for material processing

Abstract

ABSTRACTA pulsed direct current (DC) discharge ring–shaped plasma source has been proposed using single pole magnet arrangements, including a center magnet, with magnets in the setups (a): one circle, (b): two circles, and (c): three circles. The three-dimensional (3D) magnetic flux lines profiles, gyro–radii and Hall parameters of the electrons and ions, the electrical discharge characteristics, the temporal evolutions of the ion saturation currents were investigated to characterize the proposed plasma source. The calculated electron gyro–radii, re were 0.17, 1.64, 5.82 mm for setups (a), (b), and (c), respectively. The strong ring–shaped plasma discharges was observed for all setups. The typical discharge voltages were 1.0, 0.6, and 0.6 kV for setups (a), (b), and (c), respectively. The ion saturation currents, Iisat were 1.44, 2.88, and 2.2 mA for setups (a), (b), and (c), respectively at r = 45 mm and t = +10 μs. The Iisat of setup (b) is less fluctuating, whereas Iisat of setup (a) and (c) is highly variable in all positions, so that setup (b) has the best profile among the setups.