Stability enhancement of a low initial density hollow gas-puff <i>z</i> pinch by <i>e</i>− beam preionization

Abstract

e − beam preionization of the initial gas column of the hollow gas-puff z pinch at the University of California, Irvine is shown to decrease the amplitude of Rayleigh–Taylor instabilities which disrupt the imploding plasma shell of low initial density (&amp;lt;1×1017 cm−3) helium pinches. A 5-ns pulsed nitrogen laser Mach–Zehnder interferometer compares the plasma density profile at various times during the implosion for preionized and unpreionized pinches. Also, a B-dot current probe compares the plasma induction fluctuations of the pinched state. Numerical calculations of the effects of the Rayleigh–Taylor growth for our geometry are discussed.