The effect of SOL flows on edge and core radial electric field and rotation in Tore Supra

摘要

Plasma flows, parallel to the magnetic field, that can reach plasma sound speed, are known to exist in the Scrape-Off Layer (SOL) region in tokamaks. These flows are commonly observed to be highly asymmetric and their flow direction depend on magnetic configuration whether a limited or a diverted plasma is considered. While several mechanisms may be important in the generation of such asymmetry (large scale drifts, Pfirsch-Schlüter currents,…etc), the strong ballooning of the radial transport seems to play the dominant role [1, 3]. All these flows are known to impose boundary conditions which can affect the core plasma rotation. In Alcator C-Mod, it was shown that flow momentum can couple across the separatrix inducing co or counter current increment in central plasma rotation of the same sign of the flow in the SOL. The exact underlying mechanisms and their influence on spontaneous rotation are still not completely understood [1, 2]. In particular, the possible link between perpendicular (E x B drifts) and parallel flows remains an open question.