FESTR: Finite-Element Spectral Transfer of Radiation spectroscopic modeling and analysis code (New Version Announcement)

Abstract We report on the release of a new version of the FESTR (P. Hakel, Comput. Phys. Commun. 207 (2016) 415–425., https://github.com/LANLhakel/FESTR ) spectral postprocessor of hydrodynamic simulations of hot, dense plasmas . Based on given time histories of one-, two-, and three-dimensional spatial distributions of materials, and their local temperature and density conditions, spectroscopically-resolved signals are computed. The effects of radiation emission and absorption by the plasma on the emergent spectra are simultaneously taken into account. This program can also be used independently of hydrodynamic calculations to analyze available experimental data with the goal of inferring plasma conditions. NEW VERSION PROGRAM SUMMARY Program Title: FESTR Program Files doi: http://dx.doi.org/10.17632/npvtbd7kfg.2 Licensing provisions: BSD 3-clause license Programming language: C++ Journal reference of previous version: P. Hakel, Comput. Phys. Commun. 207 (2016) 415–425. Does the new version supersede the previous version?: Yes Reasons for the new version: Parallelization , bug fixes, new features and copyright Summary of revisions: The copyright notice was changed to reflect the transition of the Los Alamos National Laboratory MO the makefile now takes additional command-line arguments to invoke these capabilities. The makefile was generalized to use wildcard functionality and placed into the new directory named “common” along with MPI and unit-test relevant source files. Object files are now assembled into library (“*.a”) archive files before linking with the object file containing the “main” function (this change should facilitate the reuse of FESTR functions in other possible future projects.) New “tracking” members were added to classes Detector and Ray to mark whether partial spectral results (along the specified Rays) should also be output (the default is “no” i.e., “false”); relevant unit tests were added or modified accordingly. Several bugs were found and corrected. Additional details and the full history of the development of this program can be found in the “README.md” and “about.txt” files located in the top directory of this package. Nature of problem: Calculation of spectral signals by postprocessing hydrodynamics simulations. Analysis of experimental spectroscopic data to infer plasma temperature and density conditions, and its chemical composition. Simultaneous treatment of spatial non-uniformity (on 3D unstructured meshes) along with spectroscopic-quality radiation transport. Solution method: Rays are cast across a 3D unstructured mesh that characterizes local temperature, density, and chemical composition of the material. Analytic solution to the 1D (along the ray) steady-state, local radiation transport equation is repeatedly used to gradually build a synthetic spectrum for each ray. Restrictions: Steady-state approximation of the radiation transport equation is used. Scattering as a radiation source is not included. Given plasma conditions are considered fixed; potential feedback of computed radiation back into plasma temperature and equation-of-state is neglected. Doppler shifts are not modeled at this time. The quality of the computed results critically depends on the accuracy of external atomic databases used as input by FESTR. Polygon objects are assumed to be convex at present.