RF Confinement of a Plasma by Two Cylindrical Electrodes

Abstract

Electron contribution in the RF confinement of a mirror plasma by two cylindrical electrodes is reported. It is effective at a frequency corresponding to a parallel resonance including the electrode and the plasma. The plasma is sufficiently confined by a voltage of 40 volts, peak to peak, externaly applied to the plasma with an electron density n_e∼10¹⁰ cm⁻³ and an electron temperature T_e∼20 eV. The plugging force for the confinement is caused by the electric field E_z parallel to the mirror axis, which produces the ponderomotive potential in electrons, and ions are confined by the ambipolar electric field. The measured distribution of the space potentials can explain well that the plasma is confined by RF field between two cylindrical electrodes.