Mathematisch-Naturwissenschaftliche Fakultät

Institut für Physik

Fachgebiet: Plasma Physics

Betreuer: Prof. Dr. Gerd Röpke

M. Sc. Banaz Omar
(e-mail: )

Spectral Line Broadening of He I and He-like Ions in Dense Plasmas

Based on a quantum statistical many-particle approach, the spectral line shapes is presented for He I and He-like ions in dense plasmas. The electronic contributions to the shift and width are considered using the method of thermodynamic Green's function. Dynamical screening of the electron-atom interaction is included. A cut-off procedure for strong collisions is used. The contribution of the ions is taken into account in a quasi-static approximation, with both the quadratic Stark effect and the quadrupole interaction. The Coulomb approximation is employed to evaluate the wavefunctions. Stark broadening of most famous isolated He I in dense plasmas are calculated. The over all good agreement can be clearly seen by comparing our results with a large number of available theoretical and experimental data.

Furthermore, the brilliance spectra of C V plasma generated by subpicosecond high intensity laser pulses are analyzed. The plasma parameters such as electron density and temperature are determined. Synthetic carbon He-α and He-β line profiles are calculated for the inferred plasma parameters by assuming local thermal equilibrium. Self-absorption is taken into account considering one dimensional radiation transport equation. Linear Stark effect appears at high electron density and leads to forbidden transitions, which are overlap with the He-β line. The comparison between the measured spectrum and our calculated synthetic profile is good for He-α, while discrepancies are found in the case of He-β line.