A software package for rigorously calculating optical plasma spectra and automatically retrieving plasma properties

Abstract

A free software package code named OPSIAL (Optical Plasma Spectral Calculation And Parameters Retrieval) for rigorously calculating optical plasma spectra and for automatically retrieving plasma parameters is presented. OPSIAL calculates the absolute spectral radiance due to the bound–bound transitions of elemental species in the plasma by rigorously solving the equation of radiative transfer using an ultrafast line-by-line algorithm. OPSIAL supports both local-thermodynamic-equilibrium (LTE) and partial LTE conditions and takes account of line broadenings due to the Doppler effect and collisions with electrons and other pseudo colliders in the plasma. An algorithm for automatically identifying elemental species and retrieving plasma parameters based on observed plasma emission spectra has also been implemented into OPSIAL. The structure and theoretical framework of OPSIAL are presented together with a case study of using OPSIAL to analyze laser-induced breakdown spectral data of the ChemCam instrument onboard the Mars rover Curiosity.