On the asymmetry of lines emitted by one-electron ions in very dense plasmas

Positions and relative intensities of Stark components of lines are altered in very dense plasmas because free electrons partially screen not only the Coulomb interaction between the radiating ion and perturbing ions, but also the Coulomb interaction within the radiating ion itself. This latter plasma-screening perturbation and the perturbation caused by the ion-field gradient (quadrupole interaction) are comparable. The first-order corrected Stark patterns for Lyman- alpha lines of several ions are presented in order to demonstrate the necessity of considering both of these perturbations and the fine-structure interaction simultaneously in the calculation of line profiles for high-density plasmas.