Time-dependent electron temperature diagnostics for high-power, aluminum z-pinch plasmas

Abstract

Time-resolved x-ray pinhole photographs and time-integrated radially-resolved x-ray crystal spectrometer measurements of azimuthally-symmetric aluminum-wire implosions suggest that the final pinch is composed of a hot dense plasma core surrounded by a cooler plasma halo. The slope of the free-bound x-ray continuum measured using filtered photoconducting diodes, provides a time-resolved, model-independent diagnostic of the core electron temperature. A simultaneous measurement of the time-resolved K-shell line spectra provides a diagnostic to indirectly measure the electron temperature of the plasma halo. Together, measurements from the two diagnostics lend support to a picture that also emerges from a 1-D Rad-Hydro model; namely, that of a plasma whose thermalization on axis produces steep radial gradients in temperature, where the temperatures are substantially in excess of a kilovolt in the core and below a kilovolt in the surrounding plasma halo.