SOLPS-ITER simulations of an X-point radiator in ASDEX Upgrade
The X-point radiator (XPR), a cold, dense and highly radiating plasma volume above the X-point, could be an important element of power exhaust in fusion reactors.
(b) the poloidal cross-section of line radiation density in the simulation with an XPR.
The SOLPS-ITER code has been applied to study the XPR phenomenon in ASDEX Upgrade. The two-dimensional simulations showed a good agreement with the divertor Thomson scattering measurements, especially when drifts and currents are activated in the simulation (see Figure (a)). Above the X-point, a cold XPR core with volumetric recombination was found with an electron temperature of about 1 eV, which is surrounded by highly radiating and ionizing bands with a temperature of about 10 eV (see Figure (b)). The simulation results reproduced the prediction in a reduced model [Stroth et al., Nuclear Fusion 2022]. Neutrals penetrating from the adjoining cold divertor region and the large flux expansion near the X-point play an important role in initiating an XPR.
O. Pan et al., 2023 Nucl. Fusion 63 016001 https://doi.org/10.1088/1741-4326/ac9742