Pfirsch-Schluter currents in the jet divertor

Naturally occurring electric current spatial profiles were measured at high spatial resolution by a probe array installed in the JET Mark 1 divertor target. Very narrow current layers near the separatrix strike point on the divertor target were observed. The current flow directions in the narrow layers changed with toroidal field direction. The currents do not behave like previously identified thermoelectric currents. A plasma plus neutral quasi-single-fluid MHD model is developed to adequately represent the scrape-off layer (SOL) equilibrium all the way through the divertor recycle zone and sheath to the target. The model shows that SOL Pfirsch-Schluter current passes through these zones relatively unattenuated and is measurable by target mounted probes. The observed new current features are consistent with being SOL Pfirsch-Schluter currents. Some possible consequences to the equilibrium when the Pfirsch-Schluter current is reduced by divertor plasma detachment from the target are briefly discussed.