Atomic Processes, Including Photoabsorption, Subject to Outside Charge-Neutral Plasma

Tu-Nan Chang,Xiang Gao,Chensheng Wu,Te-Kuei Fang

doi:10.3390/atoms10010016

Abstract

We present in this review our recent theoretical studies on atomic processes subject to the plasma environment including the α and β emissions and the ground state photoabsorption of the one- and two-electron atoms and ions. By carefully examining the spatial and temporal criteria of the Debye–Hückel (DH) approximation based on the classical Maxwell–Boltzmann statistics, we were able to represent the plasma effect with a Debye–Hückel screening potential VDH in terms of the Debye length D, which is linked to the ratio between the plasma density N and its temperature kT. Our theoretical data generated with VDH from the detailed non-relativistic and relativistic multiconfiguration atomic structure calculations compare well with the limited measured results from the most recent experiments. Starting from the quasi-hydrogenic picture, we were able to show qualitatively that the energy shifts of the emission lines could be expressed in terms of a general expression as a function of a modified parameter, i.e., the reduced Debye length λ. The close agreement between theory and experiment from our study may help to facilitate the plasma diagnostics to determine the electron density and the temperature of the outside plasma.

Highlights

IntroductionReliable data for many of the atomic processes subject to the outside charge-neutral plasma are important for the numerical modeling of the evolution of many processes for the energy-related controlled fusion program and some of the astrophysical systems [1,2,3,4]
The main objective of this review is to summarize a series of recent studies based on the Debye–Hückel (DH) model, proposed before the quantum mechanics was fully developed [17], on the atomic processes in the plasma environment
For the effect of the outside plasma on the oscillator strength f for the α and β emissions of the H-like and He-like ions, we focus our discussion to those presented above in terms of its variation as a function of the reduced Debye length λ

Summary

Introduction

Reliable data for many of the atomic processes subject to the outside charge-neutral plasma are important for the numerical modeling of the evolution of many processes for the energy-related controlled fusion program and some of the astrophysical systems [1,2,3,4]. By including the interactions between the atomic electrons and the outside plasma, attempts have been made with somewhat detailed theoretical methods [5,6,7,8,9,10,11,12,13] to generate data that may understand the limited experimental measurements One such example is the application of the ion sphere (IS) approach [8,9,10]. By including the Debye screening, which effectively reduces the Coulomb repulsive interaction between atomic electrons, a high-precision theoretical calculation has led to the spurious conclusion that the only known bound state of H − between two loosely bound electrons would stay bound even in the presence of a strong outside plasma [34,35]. To fully take advantage of the general feature in terms of the reduced Debye length for the transition energy shifts as a plasma diagnostic possibility, further high-precision experiments are necessary for a better determination of the range of the radius A of the Debye sphere

Debye–Hückel Approximation and the Calculational Procedure

Plasma Effects on H-like and He-like Ions

Photoabsorption

Findings

Conclusions