Investigation of the mechanism for current switching from the outer gas puff to the inner wire array in a structured Z-pinch

Experiments are reported on the implosion of structured loads with outer ar gon, krypton, and xenon gas puffs and an inner tungsten multiwire array. Ex periments were carried out in the GIT-12 generator with a current of 2.6 MA and a current rise time of 270 ns. It is shown that the current successful ly switches to the wire array only when the gas puff is sufficiently light. The total implosion time is 300 ns, and the implosion time of a wire array , determined from streak camera images, is 50-70 ns. It is suggested that t he switching is efficient only when the active impedance of the gas puff is higher than the transitional resistance of the electrically exploded wires . (C) 2001 MAIK "Nauka/Interperiodica".