Magnetically-controlled gas breakdown anode plasma sources for magnetically-insulated ion diodes

Summary form only given, as follows. A magnetically insulated extraction-geometry ion diode using inductive breakdown of a gas layer to produce a magnetically controlled anode plasma (MAP) has been successfully operated on the Longshot pulser (120 kV, 30 kA, ⩽μs). This Longshot diode doubled the total ion output compared to a standard dielectric anode, allowed constant impedance for >500 ns, and improved upon all other characteristics except beam divergence. The MAP source has now been integrated into a similar diode to operate on the Neptune pulser (700 kV, 3 Ω, 100 ns, >0.1 TW). The goal is to investigate the scaling of this diode to the higher voltage and to a current density above 0.5 kA/cm². The major scaling issue is whether good control of the anode surface shape and position, and the resulting ion canonical momentum and divergence, can be maintained. The Neptune MAP source, with an improved inductive preionizer, produces plasmas of better uniformity than Longshot