EXPERIMENTAL STUDIES ON ION DIODES AND THEORETICAL STUDIES ON ION BEAM FOCUSING BY MAGNETIC LENS

摘要

Experimental investigation of factors that determine the optimum performance of magnetically insulated ion diodes for light ion inertial confinement fusion (ICF) indicates that degradation of both ion production efficiency and beam divergence occurs when current densities of above about 1.5 kA/cm~2 are extracted from passive flashover ion sources on the 1 MV, 4 Ω, 40 ns LION accelerator. Observations of these phenomena are complicated by ablation effects on ion diagnostics at high beam fluences. Theoretical studies of ion beam propagation through plasma filled magnetic lens focusing systems for ICF show that the plasma response is in a whistler wave dominated regime. Criteria are developed for lens and plasma parameters that allow self-field perturbations of the beam to be small enough for good beam transport to an ICF target.