Spectroscopic diagnosis of foam z-pinch plasmas on SATURN

Solid and annular silicon aerogel and agar foams were imploded on the SATURN accelerator to study plasma initiation, acceleration, and stagnation. SATURN delivers 7 MA with a 50 ns rise time to these foam loads. We fielded several spectroscopic diagnostics to measure plasma parameters throughout the z-pinch discharge. A spatially resolved single frame time-gated extreme ultraviolet spectrometer measured the extent of plasma ablation off the surface of the foam. A time integrated crystal spectrometer showed that characteristic K shell radiation of silicon in the aerogel and of sulfur and sodium impurities in the agar were attenuated when the foam loads were coated with a conductive layer of gold. A time-resolved pinhole camera showed that in general the quality of the pinch implosions was poor but improved with increasing efforts to improve current continuity such as prepulse and conductive coatings.