Formation of cathode plasma in a magnetically insulated high-current diode to generate negative hydrogen ions with current densities up to 200 A/cm2

Abstract

High-power pulsed beams of neutral atoms may be useful for CTR as alternative ways to drive the target. They can be obtained by stripping high-current negative ion beams. Experiments are described on cathode plasma formation with sufficient negative hydrogen ion concentration to obtain H− current density up to 200 A/cm2. The plasma was formed by a surface discharge on a dielectric initiated by a bipolar prepulse or by laser illumination. It is shown that the electron current density flowing through the cathode plasma needs to be greater than 104 A/cm2 to create H− continuously in the outer region of the plasma and thereby produce H− current densities up to 200 A/cm2.