No abstract

We report on a single-state measurement of electrical conductivity of warm dense gold in the solid to plasma transition regime. This is achieved using the idealized slab plasma approach of isochoric heating of ultrathin samples by a femtosecond laser, coupled with femtosecond probe measurements of reflectivity and transmission. The experiment also reveals the time scale associated with the disassembly of laser heated solid.

A spatially resolving visible light detector system has been constructed and used to measure continuum radiation in the wavelength region near 5360 A on the Alcator C tokamak. The instrument measures the line integral brightnesses from 20 chords through the plasma. For high electron temperature regimes and relatively line-free wavelength regions, Zeff(r,t) is inferred from Abel inverted brightness profiles.During the steady-state portion of the discharge, Zeff(r) is usually found to be constant within 10% out to r/a = .75.