Leveraging high temporal and spectral resolution to study solid-density plasma ablation
POSTER
Abstract
X-ray emission spectroscopy is a key diagnostic for laser-produced plasmas, especially at high densities where most optical- and particle-based measurement techniques cannot probe. We investigate plasma phenomena near solid densities by pairing an ultrafast streak camera (temporal resolution Δt < 1 ps) with focusing quartz crystal spectrometers (spectral resolving power E/ΔE ~ 104) to capture the evolution of emitted x-ray line shapes. Since line shapes encode plasma properties such as densities, temperatures, and flows, the measurements access new information about high-density plasma physics. One application of this capability is the study of solid material ablation by relativistic laser pulses (intensity > 1021 W/cm2). Streaked x-ray spectra emitted from discrete layers of highly ionized tracer material contain unshifted x-ray line transitions at early times, representative of hot, non-flowing plasma. Later in time, the same line shapes develop Doppler-shifted components, indicating time-evolving ion flows as plasma ablates into vacuum. This data can quantify a nonzero and depth-dependent time delay between laser-induced plasma heating and the initiation of expansion.
*This work was supported by the DOE Office of Science, Fusion Energy Sciences under Contract No. DE-SC0021246: the LaserNetUS initiative at Colorado State University's Advanced Beam Laboratory, and was performed under the auspices of the U.S. Department of Energy by Princeton Plasma Physics Laboratory under Contract. No. DE-AC02-09CH11466 and by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.
Publication:Kraus, B. F. et al. "Streaked Sub-ps-resolution X-ray Line Shapes and Implications for Solid-density Plasma Dynamics," submitted to Rev. Sci. Instrum. for the 24th Topical Conference on High-Temperature Plasma Diagnostics. Under review. Kraus, B. F. et al. 1 publication planned for 2022, journal unknown.
