ABSTRACT This work is devoted to the formation of an Upper X‐point Radiator (UXPR) in the upper part of a tokamak with a double‐null divertor configuration and lower active X‐point. The study is based on SOLPS‐ITER modelling of the Globus‐M2 tokamak with nitrogen seeding, considering three scenarios with 58%, 65%, and 77% of radiated power at a constant 0.7 MW input power. Two distinct formation mechanisms are identified: for the low radiation scenario (58%), the radiating zone develops due to the neoclassical perturbation of ion temperature and electron density; while for the high radiation scenario (77%), the dense region appears for main ions, electrons, and impurity self‐consistently with the temperature decrease caused by radiation. The high radiation scenario is accompanied by the growth of impurity recycling at the upper divertor surfaces and ionization source under the upper X‐point. A detailed analysis of heat and particle balances is provided.
Dolgova et al. (Wed,) studied this question.