Measurements of plasma opacity from laser-produced optically thin strongly coupled plasmas

A new technique for producing dense (${10}^{20}$ ${\mathrm{cm}}^{\mathrm{-}3}$), low-temperature (2–6 eV), optically thin, and well characterized laser-produced plasmas is used to measure, for the first time, the inverse bremsstrahlung absorption and the Coulomb logarithm at 0.5 μm in a strongly coupled plasma. Extrapolations of the standard high-frequency calculations of inverse bremsstrahlung absorption underestimate the absorption in this regime by a factor of 2 or more, whereas calculations based on strongly coupled plasma theory and static classical theory agree with the measurements.