Atomic and molecular plasma spectroscopy in the laboratory for interpretation of astrophysical white dwarf star signatures

This work discusses atomic and molecular spectroscopy of laboratory laser plasma and analysis of selected star spectra. Time-resolved atomic hydrogen line-of-sight measurements yield electron density and excitation temperature. Equally, selected diatomic molecular recombination spectra are measured to infer excitation temperature following optical breakdown in standard ambient temperature and pressure air, and in selected gas mixtures. The recorded and fitted experimental data are compared with available absorption spectra from selected white dwarf stars. Spectral signatures are presented from alpha canis majoris B and alpha canis minoris B, or Sirius B and Procyon B, respectively, and from other selected white dwarfs. Applications of atomic hydrogen and diatomic molecular diagnostics are of interest, including reconciliation of hydrogen Balmer alpha and beta time-resolved plasma-line profiles and red-shifts with white-dwarf, gravitational red-shifts and details of hydrogen absorption profiles. Selected astrophysical white dwarfs reveal equivalent widths that are typically one order of magnitude larger than those for the sun. Current research efforts in laboratory plasma physics extend to studies of hyper-sonic expansion dynamics subsequent to laser-induced breakdown, determination of electron densities and atomic and molecular species distributions, atomic spectral line shapes, and molecular band appearances. These topics are also contents of current astrophysical research, including interpretation of measured white-dwarf absorption profiles and modeling of atmosphere compositions.