Electron beam effects on the spectroscopy of multiply charged ions in plasma focus experiments

Argon-hydrogen mixture plasma focus experiments performed at the Warsaw Ins titute of Plasma Physics and Laser Microfusion show detailed space resolved spectra for Ar K-shell satellite lines up to F-like Ar and K-alpha of Ar. These transitions originating from autoionizing levels are caused by collis ions of ions with the energetic electron beams which are created by the con strictions of the plasma column due to the development of magnetohydrodynam ic instabilities. A collisional-radiative model was constructed using a non -Maxwellian electron energy distribution consisting of a thermal Maxwellian part plus a Gaussian part to represent the high-energy electron beam. The shapes of the observed satellite structures are consistent with the calcula ted spectrum for electron temperatures between 20 and 230 eV, and beam dens ities of about 10(-3) times the plasma electron density. (C) 1999 Elsevier Science Ltd. All rights reserved.