Time Resolved Spectroscopic Measurements of Electron Temperature and Ion Density in a High Repetition Rate Experiment

POSTER

Abstract

Many laboratory plasmas of interest are transient (\textless 1 ms) and tenuous (\textless 10$^{\mathrm{15}}$ cm$^{\mathrm{-3}})$ in nature, but measuring time-resolved temperatures and densities in this regime is challenging. The intensity ratios of spectral lines corresponding to successive ionization states are highly dependent on electron temperature, and Stark broadening is a well-established and reliable technique for determining density. However, these techniques are generally performed on steady-state plasmas, or time integrated to the point where valuable information is lost. We present a comparison between high-temporal resolution (\textasciitilde 10 ns) spectroscopic data and a collisional-radiative model in order to characterize the evolution of the temperature and density of carbon ablated plasma in a regime where Thomson scattering and Langmuir probes prove challenging. A high repetition rate laser allows for individual time resolved spectral lines to be assembled into a highly resolved (\textasciitilde 2 {\AA}) composite spectrum for analysis.

*This work was supported by the Defense Threat Reduction Agency, Lawrence Livermore National Security LLC, and the United States Department of Energy (DOE) under Contract No. DE-SC0017900

Authors

  • Robert Dorst

    • University of California, Los Angeles

  • Peter Heuer

    • University of California, Los Angeles

  • Derek Schaeffer

    • Princeton University

  • Jessica Pilgram

    • University of California, Los Angeles

  • Carmen Constantin

    • University of California, Los Angeles

  • Christoph Niemann

    • University of California, Los Angeles