Electric field distribution in plasma during ion extraction by a radio frequency resonance method

An ion extraction method using plasma-sheath resonance in a weak magnetic field has been employed to measure the electric field distribution and the time-resolved potential distribution experimentally. The Xe discharge plasma is sandwiched by parallel plate electrodes, which are set parallel to the magnetic field, When resonance occurs at 10 MHz, the electric field perpendicular to the magnetic field has its peak at the midpoint of the electrodes' length. Therefore, a standing wave seems to be induced in the electrodes. When measuring the time-resolved potential distribution perpendicular to the magnetic field at the midpoint of the electrodes' length, potential gradients are formed and their directions are reversed in one rf period. It is, therefore, verified that the rf electric field penetrates to the plasma. Moreover, simulation results show that the electric field strength in the resonance increases, but nonlinearly, with the applied voltage. (C) 1997 American Institute of Physics.