Drift effects in SOLPS-ITER simulations for the TCV divertor upgrade

This contribution reports on the progress towards including drift effects in SOLPS-ITER simulations to assess power distribution and detachment onset in the light of the 2019 TCV divertor upgrade [1]. The installation of in-vessel gas baffles (Figure 1a) is predicted to increase the divertor neutral density by a factor ∼ 5 and therefore facilitates the access to detachment [2]. The conditions for the onset of detachment at each strike point depend on the power entering each divertor leg and thus simulations must correctly include the power distribution between the inner and outer divertor that is greatly affected by scrape-off layer drifts. Surprisingly, the sharing of particles and heat between the targets in reversed field conditions is found to be shifted towards the outer target. This counter-intuitive flowpattern is due to an electric potential well below the X-point that occurs in high density reversed field simulations.