The effect of doubly excited states on emission line ratios and absolute powers used in spectroscopic diagnostics

摘要

Emission line ratios have been used as an effective diagnostic for the determination of the plasma parameters. However, the treatment of doubly excited states in such models can affect the ionization dynamics which can subsequently alter the emission line ratios and absolute powers used for plasma diagnostics. Prior models have also assumed that the electron energy distribution function (EEDF) is Maxwellian, but previous experiments have measured electron beams and Ka line emission. The Ka emission was produced as a result of the electron beams ionizing an inner-shell electron from lower ionization stages. The presence of such hot electrons suggests that the EEDF is simply not Maxwellian and requires a modification in the high energy tail. These high energy electrons can also produce doubly excited ions with inner-shell vacancies, alter the ionization kinetics, and furthermore impact line ratios used to determine the plasma parameters. The effect of doubly excited states on emission line ratios and absolute powers from a multi-zone non-LTE copper pinch model with radiation transport using coupling coefficients will be presented and discussed in light of experimental data.