X-ray spectropolarimetry of high-current x-pinch plasmas

Summary form only given, as follows. The development of time-dependent K-and-L-shell spectroscopic monitoring of high-temperature and high-density z-pinch plasmas necessitates accounting for non-maxwellian electron distribution functions and polarization properties of X-ray lines. The existence of strong electron beams in x-pinch plasmas motivated the development of a new tool, X-ray spectropolarimetry, for investigating the anisotropy of such plasmas. This diagnostic includes both space- and time-resolved X-ray spectroscopy and polarimetry and is based on the theoretical modeling of X-ray line polarization-dependent spectra measured simultaneously by spectrometers with different sensitivities to polarization. Specifically, K-shell Ti and L-shell Mo X-ray spectra have been thoroughly modeled. Experimental spectra have been generated by Ti and Mo x-pinch plasmas produced at the Nevada Terawatt Facility. The detailed spectroscopic analysis of more than 20 shots with these x-pinches shows how X-ray spectropolarimetry complements the usual spectroscopic monitoring of z-pinch plasmas and demonstrates the importance of accounting for hot, non-maxwellian electrons in plasma diagnostics. The present work is supported by DOE, SNL, and UNR.