Screening effect of partially ionized high-Z impurities in relativistic electron Fokkerr-Planck calculations and runaway electron dynamics

Abstract

In this report, the problem of tungsten impurities in tokamak plasmas is introduced and the related phenomenon of partial screening occurring during Coulomb collisions between suprathermal electrons and tungsten impurity ions is discussed. The report also introduces the first code among a chain of numerical tools: ALOHA, C3PO, LUKE and R5X2, available for collaborators in CEA Cadarache, where the WEST tokamak is located. This chain of codes has recently been upgraded to take into account the partial screening effect. This set of tools will allow to carry out statistical investigations on the impact of partial screening on the fast electron dynamics in tokamak plasmas.