X-ray back-lighter characterization for iron opacity measurements using laser-produced aluminium K-alpha emission

a K Rossall (1) , L M R Gartside (1) , S Chaurasia (2) , S Tripathi (1) , D S Munda (1) , N K Gupta (1) , L J Dhareshwar (1) , J Gaffney (3) , S J Rose (1) , G J Tallents (1) , Tel

1 Dept. Of Physics
2 Laser and Neutron Physics Section
3 Imperial College of Science, Technology and Medicine

Aluminium K α emission (1.5 keV) produced by an 8 J, 500 ps, Nd:Glass laser incident at 45° onto a layered target of 0.8 µm thick aluminium (front side) and 1µm thick iron (back side) has been used to probe the opacity of iron plasma. Source broadened spectroscopy and continuum emission analysis shows that whole beam self focussing within the aluminium plasma results in a two temperature spatial distribution. Thermal conduction from the laser-irradiated aluminium into the iron layer, enhanced by the whole beam self focusing, results in iron at a temperature of ~ 10 – 150 eV. The iron opacity at photon energy of 1.5 keV is shown to be strongly modified from cold values in agreement with IMP code opacities. Results presented here represent a feasibility study to seed future work using table top laser systems for plasma opacity experiments.

Mots clés: 52.50.Jm; 52.25.Os; 52.38.Hb

a K Rossall, L M R Gartside, S Chaurasia, S Tripathi, D S Munda, et al.. X-ray back-lighter characterization for iron opacity measurements using laser-produced aluminium K-alpha emission. Journal of Physics B: Atomic, Molecular and Optical Physics, 2010, 43 (15), pp.155403. ⟨10.1088/0953-4075/43/15/155403⟩. ⟨hal-00569820⟩