Electrostatic Ion-Acoustic Shocks Produced by Density Steps

Abstract

Large-amplitude ion-acoustic shocks are produced by superposition of a pulsed photo-ionized plasma slab on a dc background. The Mach number $M$ increases as a function of the step ratio $R$ up to a maximum of $M\approx 2.5$ for $R=20\mathrm{}$. Above $R=5\mathrm{}$ and a shock jump of $\frac{\Delta n}{n}\approx 1$, the shock widths start to broaden severely with distance from the source.