Influence of the E × B drift in high recycling divertors on target asymmetries
Detailed analysis of convective fluxes caused by E × B drifts is carried out in a realistic JET configuration, based on a series of EDGE2D-EIRENE runs. The EDGE2D-EIRENE code includes all guiding centre drifts, E × B as well as ∇B and centrifugal drifts. Particle sources created by divergences of radial and poloidal components of the E × B drift are separately calculated for each flux tube in the divertor. It is demonstrated that in high recycling divertor conditions radial E × B drift creates particle sources in the common flux region (CFR) consistent with experimentally measured divertor and target asymmetries, with the poloidal E × B drift creating sources of an opposite sign but smaller in absolute value. That is, the experimentally observed asymmetries in the CFR are the opposite to what poloidal E × B drift by itself would cause. In the private flux region (PFR), the situation is reversed, with poloidal E × B drift being dominant. In this region poloidal E × B drift by itself contributes to experimentally observed asymmetries. Thus, in each region, the dominant component of the E × B drift acts so as to create the density (and hence, also temperature) asymmetries that are observed both in experiment and in 2D edge fluid codes. Since the total number of charged particles is much greater in the CFR than in PFR, divertor asymmetries caused by the E × B drift should be attributed primarily to particle sources in the CFR caused by radial E × B drift.
|Julkaisu||Plasma Physics and Controlled Fusion|
|Tila||Julkaistu - 2015|
|OKM-julkaisutyyppi||A1 Julkaistu artikkeli, soviteltu|