Measurements of the L-shell emission of a Laser--Heated Halfraum Using High-Resolution X-ray Spectroscopy
POSTER
Abstract
State--of--the--art 2D LASNEX simulations of the interaction between high--energy (kJ) laser pulses (ns) and gold halfraums predict plasma conditions with $T_e$ above 15 keV at $n_e \sim $ 10$^{22}$ cm$^{-3}$. At such temperatures the charge state distribution (CSD) of gold ions contains a significant fraction of Ne--like Au${69+}$ ions. Survey spectra from highly charged gold ions which have been measured at the Livermore SuperEBIT facility show that the emission lines from Au${69+}$ and its subsequent ionization stages are separated by 40 eV or more. Thus, the CSD can be determined spectroscopically by measuring the relative line intensities. We have developed a high--resolution transmission crystal spectrometer to observe the x--ray emission in the vicinity of the $3d_{5/2}$ --- $2p_ {3/2}$ transition of Au${69+}$ (10.5 keV), i.e., 1000 eV spectral range around 10.2 keV. We present survey spectra obtained at SuperEBIT/LLNL and x--ray emission spectra from a laser--heated halfraum experiment performed at OMEGA/LLE.
*This work was performed under the auspices of the U.S.DOE by UC LLNL under contract No. W-7405-Eng-48 and supported by the U.S.DOE NLUF grant DE-FG52-2005NA26017.