Analysis of L-shell line spectra with 50-ps time resolution from Mo X-pinch plasmas -: art. no. 026402

Mo wire X pinches typically emit several x-ray bursts from a bright spot near the crossing of the X-pinch wires. Streak camera images of L-shell line emission from Mo wire X pinches have been analyzed using a non-local thermodynamic equilibrium (NLTE) collisional-radiative atomic kinetics model, providing temperature and density profiles with similar to50 ps time resolution over the similar to350 ps x-ray bursts. In conjunction with nonspectroscopic measurements, the analysis is used to propose a picture of the dynamic evolution of the X-pinch plasma. The L-shell spectra from the first x-ray burst indicate an electron density near 10(22) cm(-3) and an electron temperature near 1 keV; subsequent x-ray bursts have L-shell spectra that indicate electron temperatures slightly above 1 keV and electron densities near 10(20) and 10(21) cm(-3). The size of the L-shell line-emitting region is estimated to be near 10 mum for the first x-ray burst and much larger for the later bursts. It is proposed that inner-shell excitation of low ionization stages of Mo in a mum-scale plasma region contributes to the observed radiation from the first micropinch, which typically emits a short burst of >3 keV radiation and has L-shell spectra characterized by broad spectral lines overlaying an intense continuum.