Time-resolved spectroscopic measurements of ∼1 keV, dense, subnanosecond X-pinch plasma bright spots

Abstract

Bright, ∼1 μm x-ray sources (micropinches) produced within exploding wire X pinches are found to be near solid density and ∼1 keV electron temperature. For example, with a Ti X pinch, a 90 ps lifetime, 1.5–1.8 keV electron temperature, ${\text{∼10}}^{23}/{\mathrm{cm}}^3$ electron density plasma was observed. These plasma characteristics were determined using time-resolved x-ray spectra produced by 2- and 4-wire X pinches and collected by an x-ray streak camera with <10 ps time resolution. Together with a spherically bent mica crystal spectrograph, the streak camera recorded the 1–10 keV radiation emitted from X pinches made from different wire materials. Some spectra were dominated by continuum and others by line radiation. Spectral features varied on time scales ranging from 10 to 300 ps, depending on the wire material. Results are presented that demonstrate the necessity of time-resolved data for determining plasma conditions from micropinch x-ray spectra.