Free electron relativistic correction factors to collisional excitation and ionisation rates in a plasma

This paper presents approximate correction factors to collisional excitation and ionisation rates which account for special relativity in the free electron motion as a function of free electron temperature and the threshold energy of the reaction. These are calculated by taking the ratio of collisional rates derived from simple empirical cross sections using relativistic and non-relativistic mechanics. These results are extended to de-excitation and three body recombination rates using detailed balance. It is found that the relativistic correction is significant in regimes potentially important to galactic intracluster media and diagnostic dopants in burning ICF plasmas