Berlin 2014 – scientific programme

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P: Fachverband Plasmaphysik

P 8: Diagnostics I

P 8.4: Talk

Tuesday, March 18, 2014, 11:30–11:45, SPA HS201

Plasma Diagnostics Using K-Line Emission Profiles of Silicon — •Yiling Chen, Andrea Sengebusch, Heidi Reinholz, and Gerd Röpke — Universität Rostock, Rostock, Deutschland

Modifications of K-line profiles due to a warm dense plasma environment can serve for plasma diagnostics. We focus on Si K_α emissions. A high enough temperature is necessary to produce the plasma and ionize the greater part of atoms. The plasma consists of ions, atoms and free electrons with densities in the order of 10²³ cm⁻³. Thus, x-ray energies are necessary to penetrate the Si sample. In our work we focus on pure Si using LS coupling. For the isolated ions, the wave functions as well as ionization energies, binding energies and relevant emission energies are calculated using the chemical ab initio code Gaussian03. Plasma effects are considered using a perturbative approach to the Hamiltonian. Using RHF wave functions we calculate the screening effect within an ion-sphere model [1] which leads to a plasma screening shift. These energy shifts of the spectral lines are considered with respect to electron-ion and electron-electron interaction. The different excitation and ionization probabilities of the electronic L-shell and M-shell lead to a non-equilibrium charge state distribution [2]. Using this distribution we calculate spectral line profiles depending on the plasma parameters which can be used to evaluate experimental data [3].

[1] Yu. B. Malykhanov, S. V. Evseev,et al., J. Appl. Spectrosc., 79, 1 (2012). [2] J. Rzadkiewicz, O. Rosmej, et al., High Energy Density Phys. (HEDP) 3, 233-236 (2007). [3] J. Rzadkiewicz, A. Gojska, et al., Phys. Rev. A 82, 012703 (2010).