Observation of a stable dense core within an unstable coronal plasma in wire-initiated dense Z-pinch experiments.

Abstract

Dense z-pinch plasmas initiated from a single 25--100 \ensuremath{\mu}m diam aluminum wire using a 100--350 kA, 100 ns current pulse have been studied with \ensuremath{\le}1 ns time resolution. Rapid unstable expansion of a coronal plasma formed around the wire was observed with a subnanosecond pulsed nitrogen laser, while a dense core, which expanded more slowly and stably, was observed with 1--2 ns x-ray backlighting pulses. The core contained most of the initial wire mass, but there appeared to be little or no current flowing in it.