Breit interaction effect on dielectronic recombination of heavy ions

Abstract

Interaction of highly charged heavy ions with electrons is one of the most important atomic processes in high temperature plasmas, including astrophysical plasmas such as solar corona and artificial plasmas such as fusion reactor plasmas. Therefore it has been well studied to date, both theoretically and experimentally, to accumulate the atomic data required for understanding or controlling such plasmas. However, there still remains interesting subjects that receive remarkable attention from the atomic physics point of view. One of them, which is the subject of this review, is substantially large Breit interaction effects on the resonance recombination process called dielectronic recombination. The Breit interaction is a relativistic effect in the electron–electron interaction potential; it is thus generally important for highly charged heavy ions. However, in the calculation of the energy levels for heavy ions, the Breit interaction is still a small perturbation compared with the main Coulomb term. On the other hand for the dielectronic recombination, it was found that the Breit interaction can enhance the cross sections significantly. It was also found that the Breit interaction can play not only an important, but even a dominant role in determining the angular distribution of x-rays emitted in the recombination processes. This topical review introduces the recent experimental and theoretical activities to clarify the essential origin of the strong effects.