Electron Energy Distributions In Optically Ionized Helium Plasmas

Abstract

Recently, several authors have proposed that x-ray lasers pumped by rapid electron-ion recombination are feasible if cold electrons can be produced from the interaction of a high-intensity laser pulse with a gas sample [1]. Burnett and Corkum [2] have used a model based on tunneling ionization and the resulting drift energy (the quasistatic model) to predict the form of the electron energy distribution function arising from such an interaction. Initial measurements of electron energy distributions were performed at low gas density (< 1011 /cc) with conflicting results [2,3]. Recombination lasers require relatively high gas density (> 1017/cc) and additional heating mechanisms may modify the distributions measured at low gas density [4].