Studies of autoionizing states relevant to dielectronic recombination. Progress report for the third year

Abstract

An important loss process in CTR plasmas is the process of dielectronic recombination, which proceeds via autoionizing states. At this date, however, this problem is not fully understood, largely because of the nearly complete lack of fundamental atomic data on high excited autoionizing states. In this document, we outline the continuation of a program to investigate the properties of autoionizing states of alkaline earth metals by means of a novel laser excitation technique developed at SRI. This approach will allow us to study, for the first time, autoionizing states of arbitrary n, and l in a controlled environment. Specifically, we plan to measure autoionization rates and branching ratios as a function of n and l and the effects of electric fields. These experiments should yield the basic atomic data, autoionization rates, required as inputs to sophisticated model calculations of dielectronic recombination rates.