Special Issue on Spectral Line Shapes in Plasmas

Evgeny Stambulchik,Annette Calisti,Hyun-Kyung Chung,Manuel González

doi:10.3390/atoms2030378

Abstract

Line-shape analysis is one of the most important tools for diagnostics of both laboratory and space plasmas. Its reliable implementation requires sufficiently accurate calculations, which imply the use of analytic methods and computer codes of varying complexity, and, necessarily, varying limits of applicability and accuracy. However, studies comparing different computational and analytic methods are almost non-existent. The Spectral Line Shapes in Plasma (SLSP) code comparison workshop series [1] was established to fill this gap. Numerous computational cases considered in the two workshops organized to date (in April 2012 and August 2013 in Vienna, Austria) not only serve the purpose of code comparison, but also have applications in research of magnetic fusion, astrophysical, laser-produced plasmas, and so on. Therefore, although the first workshop was briefly reviewed elsewhere [2], and will likely be followed by a review of the second one, it was unanimously decided by the participants that a volume devoted to results of the workshops was desired. It is the main purpose of this special issue.

Highlights

Aix Marseille Université, CNRS, PIIM UMR 7345, 13397 Marseille, France; International Atomic Energy Agency, Atomic and Molecular Data Unit, Nuclear Data Section, P.O
Many calculation cases suggested for the first two Spectral Line Shapes in Plasma (SLSP) workshops are for simple atomic systems: the hydrogen atom or hydrogen-like one-electron ions
The effects of the directionality of the microfield fluctuations were first researched within the framework of the “standard theory” of the plasma line broadening almost four decades ago, but have largely been forgotten. This approach is recalled and comparisons with computer simulations are made in the paper by Demura and Stambulchik [5]

Summary

Hydrogen-Like Transitions

Many calculation cases suggested for the first two SLSP workshops are for simple atomic systems: the hydrogen atom or hydrogen-like one-electron ions. Atoms 2014, 2 simplest; the atomic model was further reduced by neglecting the fine structure and interactions between states with different principal quantum numbers This simplest system caused the largest discrepancies between results of various models presented at the first workshop [2] due to, apparently, different treatments of the ion dynamics effect. The effects of the directionality of the microfield fluctuations were first researched within the framework of the “standard theory” of the plasma line broadening almost four decades ago, but have largely been forgotten This approach is recalled and comparisons with computer simulations are made in the paper by Demura and Stambulchik [5]. Results of computer simulations will be found in a majority of studies in this volume By many scholars, such calculations are considered ab initio and their results regarded as benchmarks—at least for hydrogen-like transitions. Rosato et al [6] argue that caution should be exercised in the case of very weakly coupled plasmas; in the extreme limit of the ideal plasma model, even the largest supercomputers available today might not be able to achieve convergence

Isolated Lines

Applications

Conclusions