Role of E × B on in–out divertor asymmetry in high recycling/partial detachment regimes under L-mode and H-mode conditions

Abstract

The role of the E × B electric drift on background plasma and carbon impurity in–out divertor asymmetry was estimated under L-mode and H-mode conditions in the high recycling regime and partial detachment regime by using the edge plasma code SOLPS5.1. It was found that the poloidal electric drift Er × B also may play a dominant role during H-mode discharge in high recycling regime, instead of the radial electric drift Eθ × B. Moreover, it also was found that during H-mode with partial detachment both components can play simultaneously a crucial role in inducing the in–out asymmetry. Their synergistic effect can make the asymmetry much more obvious than that with either of them separately. However, Eθ × B in partial detachment during L-mode can play a main role in inducing in–out asymmetry, rather than Er × B. Besides, the role of E × B components on carbon (C) impurity in–out asymmetry was also addressed. Simulation results reveal that Er × B or Eθ × B individually have a very small effect on C impurity ions in–out asymmetry, especially Eθ × B, while their synergistic effect makes the impurity ions exhibit a much more remarkable in–out asymmetry. Moreover, it was found that the Er × B and Eθ × B drift flows in the private flux region could play a crucial role in inducing C impurity in–out asymmetry, rather than the parallel flow or electric drift flow in the upstream SOL region when only considering E × B.