X-Ray Lasers 2014 pp 411-416 | Cite as
Diagnosis of Radiation Heating in Iron Buried Layer Targets
Abstract
Extreme ultra-violet (EUV) laboratory lasers can be used to probe energy transport in laser irradiated solid targets. We report on a recent experiment undertaken at LASERIX whereby the heating of laser-irradiated targets containing a thin layer of iron (50 nm) encased in plastic (CH) was diagnosed using EUV laser (13.9 nm) back-lighter probing. The heating laser pulse duration was 35fs with focal irradiances of \(3 \times 10^{16}\)Wcm\(^{-2}\) and a deliberate prepulse 20 ps before the main pulse at irradiances of \(3 \times 10^{15}\)Wcm\(^{-2}\). A one dimensional hydrodynamic fluid code HYADES has been used to simulate the temporal variation in EUV transmission using IMP opacity values for the iron layer and the simulated transmissions compared to measured transmission values. When a deliberate prepulse is used to preform an expanding plastic plasma, it is found that radiation heating is dominant in the heating of the iron layer giving rise to a rapid decrease in EUV opacity and an increase in the transmission of the 13.9nm laser radiation as the iron ionizes to Fe\(^{5+}\) and above.
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