Self-consistent modeling of X-point MARFE and divertor detachment

Abstract Formation of high density ( n e > 10 20 m - 3 ) low temperature ( T e 2 eV ) regions on the closed flux surfaces near X-point – an X-point MARFE – in the B2-EIRENE simulations of edge plasma has been studied. The MARFE is found to form in a natural way at high gas puffing rate in both D + C and pure D plasma. Inclusion of the Ly-radiation transport and photo-excitation in the simulations turns out to be mandatory for obtaining stable steady-state solutions with MARFE. Contrary to that, at the low discharge densities the solution is not sensitive with respect to the details of the neutral transport model. In order to sort out possible numerical artifacts due to finite grid resolution, the results are verified on a high resolution grid with massively parallelized Monte-Carlo part of the code.