The first data from the Orion laser; measurements of the spectrum of hot, dense aluminium

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• 作者：D.J. Hoarty ; P. Allan ; S.F. James ; C.R.D. Brown ; L.M.R. Hobbs ; M.P. Hill ; J.W.O. Harris ; J. Morton ; M.G. Brookes ; R. Shepherd ; J. Dunn ; H. Chen ; E. Von Marley ; P. Beiersdorfer ; H.K. Chung ; R.W. Lee ; G. Brown ; J. Emig
• 关键词：Dense plasma spectroscopy
• 刊名：High Energy Density Physics
• 出版年：December, 2013
• 年：2013
• 卷：9
• 期：4
• 页码：661-671
• 全文大小：2976 K

文摘

The newly commissioned Orion laser system has been used to study dense plasmas created by a combination of short pulse laser heating and compression by laser driven shocks. Thus the plasma density was systematically varied between 1 and 10聽g/cc by using aluminium samples buried in plastic foils or diamond sheets. The aluminium was heated to electron temperatures between 500聽eV and 700聽eV allowing the plasma conditions to be diagnosed by K-shell emission spectroscopy. The K-shell spectra show the effect of the ionization potential depression as a function of density via the delocalization of n聽=聽3 levels and disappearance of n聽=聽3 transitions in He-like and H-like aluminium. The data are compared to simulated spectra, which account for the change in the ionization potential by the commonly used Stewart and Pyatt prescription; a simple ion sphere model and an alternative due to Ecker and Kr枚ll suggested by recent X-ray free-electron laser experiments. The experimental data are in reasonable agreement with the model of Stewart and Pyatt, but are in better agreement with a simple ion sphere model. The data indicate that the Ecker and Kr枚ll model overestimates substantially the ionization potential depression in this regime.