Photodetachment technique for measuring H- velocities in a hydrogen plasma

Abstract

This article reports work in progress on laser diagnostics of negative-ion transport velocity in H--ion volume sources. The plasma dynamics after the laser shot is discussed in detail, and the effect of the potential perturbation on the H- velocities is evaluated. A method of evaluation of the H- transport velocity from single-laser-beam photodetachment experiments is proposed. To substantiate this method, two-laser-beam photodetachment experiments have been effected. The velocities thus determined are pressure dependent; they correspond to H- energies in the range 0.23-0.08 eV.