RAREFACTION WAVES, SOLITONS, AND HOLES IN A PURE ELECTRON-PLASMA

The propagation of holes, solitons, and rarefaction waves along the ax is of a magnetized pure electron plasma column is described. The time dependence of the radially averaged density perturbation produced by t he nonlinear waves is measured at several locations along the plasma c olumn for a wide range of plasma parameters. The rarefaction waves are studied by measuring the free expansion of the plasma into a vacuum. A new hydrodynamic theory is described that quantitatively predicts th e free expansion measurements. The rarefaction is initially characteri zed by a self-similar plasma flow, resulting in a perturbed density an d velocity without a characteristic length scale. The electron soliton s show a small increase in propagation speed with increasing amplitude and exhibit electron bursts. The holes show a decrease in propagation speed with increasing amplitude. Collisions between holes and soliton s show that these objects pass through each other undisturbed, except for a small offset. (C) 1995 American Institute of Physics.