Effect of the generalized Breit interaction on the K-shell x-ray spectra of hot krypton plasmas

•K-shell x-ray spectra of hot krypton plasmas were simulated by using a collision-radiative model, for which the atomic parameters were generated by using the flexible atomic code (FAC).•Effects of the generalized Breit interaction (GBI) on the atomic parameters and the K-shell x-ray spectra of hot krypton plasmas have been investigated, and thus the GBI effect on the accuracy of the plasma diagnostics has been estimated.•This work will contribute to plasma diagnostics in fusion science, due to that the krypton is used as a tracer to obtain the temperature and density in the inertial confinement fusion experiments, and it is used as a coolant in magnetic confinement fusion experiments. K-shell spectra are widely used for the plasma diagnostics in fusion science and astrophysics. Here, we report on a theoretical investigation of the relativistic and QED effects, i.e., the Breit interaction (BI) or the generalized Breit interaction (GBI), on the simulation of K-shell x-ray spectra of hot krypton plasmas. The simulation was conducted using a collisional-radiative model, for which the atomic parameters were generated by using the flexible atomic code. As expected, the present work shows that the BI and GBI produce similar effects for such a light element as krypton, which maximum difference of 3.7% in the emission spectra. When comparing to results calculated with just the Coulomb interaction, the GBI affects the specific line intensity by up to 15%, thus bringing about approximately 4%, 13% uncertainties for deducing the electron density and temperature of plasmas, respectively.