Effects of divertor electrical drifts on particle distribution and detachment near the divertor target plate in DIII-D

Strong impacts of drifts on the divertor plasma in–out asymmetry and detachment are demonstrated in DIII-D with an open configuration. For forward toroidal field, BT, i.e., ion B × ?B drift toward divertor, particle flux to inner as represented by Langmuir probe measured saturation current (Jsat), exhibits a double peak structure, electron temperature, lower at target. Reversing BT direction reverses both radial poloidal E flows, leading broad profile outboard scrape-off layer (SOL) similar double-peak structure that observed target BT. The correlation temperature profiles confirms physical coupling between flow sheath boundary condition their strong impact profiles. In addition, under reversed conditions, increasing density flattens profile. However, Jsat remains high away from strike point, rendering it difficult achieve “effective” detached plasma, effective reduction heat (in far SOL). contrast, cold flat can be achieved plates