### Mathematisch-Naturwissenschaftliche Fakultät

## Institut für Physik

### Fachgebiet: Plasma Physics

Betreuer: Prof. Dr. Gerd Röpke

**M. Sc.** **Banaz** **Omar**

(e-mail: banaz.omar@uni-rostock.de )

*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.