Spectral Line Shapes in Plasmas II

Abstract

The Spectral Line Shapes in Plasmas (SLSP) code comparison workshop series [...]

Current challenges in the physics of white dwarf stars

“…Interactions between a radiating atom or ion with ions and electrons in the surrounding plasma lead to Stark broadening of spectral lines. Even after decades of studies of atomic line broadening in plasmas, the theory, as implemented in several line shape codes, remains unsatisfactory and a work in progress [244]. The theory is complex, which motivates several approximations of unknown accuracy that are variously implemented in codes [245,246].…”

Hydrogen Line Shapes in Plasmas with Large Magnetic Fields

“…The standard model provides a good estimate of the line broadening but it can be inaccurate in regimes such that the ions move significantly during the characteristic decorrelation time for the dipole (usually referred to as the "time-of-interest"; it is of the order of the inverse line width). More elaborate techniques using dedicated models and codes can be used (e.g., see reports of previous SLSP workshops [8,9]). In the following, we report on computer simulations performed using a code developed previously for tokamak plasma spectroscopy applications [10,11].…”

Quantifying the statistical noise in computer simulations of Stark broadening

“…Its advantages with respect to other models is that it is free from constraining assumptions such Email address: joel.rosato@univ-amu.fr () Preprint submitted to Journal of Quantitative Spectroscopy and Radiative TransferMarch 29, 2020 as, for example, the binary condition involved in collision operator-based approaches (impact approximation [5,6]) or the ad hoc description of the microfield dynamics used in stochastic models (like the MMM [7,8] and the FFM [9,10,11]). It has been recognized that computer simulations can serve as benchmark for line shape models; cross-checks between models and simulations have been reported in the literature and workshops [e.g., at the International Workshop on Radiative Properties of Hot Dense Matter (RPHDM), at the Spectral Line Shapes in Plasmas code comparison workshop (SLSP)] [12,13,14,15,16,17,18]. Essentially, a simulation consists in numerically integrating the time-dependent Schrdinger equation that governs the dynamics of an atom perturbed by a fluctuating electric field, itself being generated from a numerical integration of the Newtonian equations of motion for the charged particles moving in the vicinity of the emitter.…”