Modelling of the X-point radiator configuration in DTT with SOLEDGE2D-Eirene

Abstract

This work studied the feasibility of an X-point radiator (XPR) in the DTT single-null full-power scenario using the edge modelling code SOLEDGE2D-EIRENE. It predicts that the XPR is accessible in DTT using neon as seeding impurity; the accessibility to the configuration is compatible with the reduced model developed for ASDEX Upgrade and TCV. The formation of the X-point radiator in DTT leads to strong impurity and temperature redistribution with respect to standard detached plasmas and the formation of a cold volume with T${}_{\text{e}}<\text{10}\text{e}V$ as observed in other machines. The transition is sudden and had major consequences on pumping, neutral penetration and separatrix temperature. The operational window in impurity concentration between XPR formation and the plasma radiative collapse was estimated to be large. A strong bifurcation is observed at the XPR onset; the bifurcation allows for impurity seeding and concentration reduction after the XPR on-set even lower than in non-XPR standard detached cases.