Experimental Characterization of a Strongly Coupled Solid Density Plasma Generated in a Short‐pulse Laser Target Interaction

We have measured high resolution copper K α spectra from a picosecond high intensity laser produced plasma. By fitting the shape of the experimental spectra with a self‐consistent‐field model which includes all the relevant line shifts from multiply ionized atoms, we are able to infer time and spatially averaged electron temperatures ( T e ) and ionization state ( Z ) in the foil. Our results show increasing values for T e and Z when the overall mass of the target is reduced. In particular, we measure temperatures in excess of 200 eV with Z ∼ 13‐14. For these conditions the ion‐ion coupling constant is Γ ii ∼ 8‐9, thus suggesting the achievement of a strongly coupled plasma regime. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)