Divergence of the Stark collision operator at large impact parameters in plasma spectroscopy models

Joël Rosato (1) , Hubert Capes (1) , Roland Stamm (1)

1 PIIM - Physique des interactions ioniques et moléculaires

The divergence that occurs at large impact parameters in Stark collision operators is examined for low-density hydrogen plasmas. In a previous work [Rosato, Capes, and Stamm, Phys. Rev. E \textbf{86}, 046407 (2012)], we showed that the correlations between a radiating atom and the charged particles surrounding it affect the mean evolution of the atom, resulting in a mitigation of the Stark broadening near the line center. In this work, we examine the physical mechanism underlying this mitigation with an approach inspired from the standard semi-classical impact model. Our approach accounts for the atom-perturber correlations in a simple fashion, through a cut-off at large impact parameters, and embraces the impact model in the weakly coupled plasma limit. Comparisons with numerical simulations are performed and indicate a good agreement.

Domaines: Physique des plasmas [physics.plasm-ph]; Physique Atomique [physics.atom-ph]; Optique [physics.optics]

Joël Rosato, Hubert Capes, Roland Stamm. Divergence of the Stark collision operator at large impact parameters in plasma spectroscopy models. Physical Review E : Statistical, Nonlinear, and Soft Matter Physics, 2013, Vol. 88, p.035101. ⟨hal-00945452⟩