Experiments relevant to laser compression at the Rutherford Appleton Laboratory Central Laser Facility

Experiments relevant to laser compression carried out by scientists from Imperial College, Queens University of Belfast, University of Essex, University of Hull, Los Alamos National Laboratory, and the Rutherford Appleton Laboratory, at the Central Laser Facility in the United Kingdom are described. The Central Laser Facility operates a six-beam laser system at 1.05 μm or 0.53 μm, giving 1kJ or 0.5 kJ pulses x-ray backlighting and two approaches to x-ray framing cameras are described. Two phenomena relevant to compression, namely thermal conductivity and hydrodynamic instabilities are described. Thermal conductivity experiments with time resolved x-ray spectroscopy and optical interferograms measure a heat flux up to 10% of the free-streaming limit, and no 'foot' to the temperature front. Rayleigh-Taylor experiments with a single mode indicate growth rates about 0.3 times classical growth rate, with some evidence for saturation. Experiments on the symmetry of irradiation possible at λ = 0.53 μm, show that comparatively large defocci, up to d/R ≅ 4, are required