PRODUCTION AND ACCELERATION OF PULSED KILOAMPERE CURRENTS OF H- AND SUBKILOAMPERE CURRENTS OF C-, F-, I-, AND PB- IONS

Experiments on acceleration of various negative ions in a high-power c oaxial diode with magnetic insulation are described. Various methods o f initiating cathode plasma for H-production were tried: surface disch arge of a dielectric by the prepulse in two cathode configurations and laser illumination of a dielectric cathode. A new more universal meth od of cathode plasma initiation was developed, allowing us to produce various species of negative ions including metallic ones. Rather rare plasma was injected from a plasma gun at the outer surface of the anod e. This plasma penetrates partially into the diode through holes, and positive ions are extracted and accelerated by the negative prepulse o r/and main voltage pulse of the diode and bombard the cathode surface. The energy deposition and cathode plasma parameters can be easily var ied by orders of magnitude by changing near anode plasma density (by v arying charging voltage of plasma gun and time delay between plasma gu n pulse and prepulse and main voltage pulse of the diode) and ion acce leration voltage. Up to 30 A/cm2 of H- ion current density was recorde d, as well as about 1 A/cm2 for C-, 0.3 A/cm2 for F-, and 0.1 A/cm2 fo r I- and Pb-.