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P: Plasmaphysik

P 6: Diagnostik 2

P 6.2: Vortrag

Freitag, 4. März 2005, 15:15–15:30, HU 3059

Shift and Broadening of Neutral Helium Spectral Lines in Dense Plasmas — •Banaz Omar¹, August Wierling¹, Sibylle Günter², and Gerd Röpke¹ — ¹Universität Rostock, Institut für Physik, 18051 Rostock, Germany — ²Max-Planck-Institut für Plasmaphysik, 85748 Garching, Germany

Shift and broadening of several lines of neutral helium in a dense plasma are investigated. Based on a quantum statistical approach, using thermodynamic Green’s functions, the electronic contributions to the shift and width are determined. Dynamic screening of the electron-atom interaction is included. It is found that, compared to the width, the electronic contribution to the shift is more affected by dynamical screening. At high density the influence of dynamical screening is more significant. A cut-off procedure for strong collisions is used. The effect of the ions is taken into account in a quasi-static approximation, with both the quadratic Stark effect and the quadrapole interaction included. Good agreement of our results for shift and width compared with the available experimental and theoretical data is achieved. As an application, the He-α profile for densities and temperatures by laser heating of plasma is studied.