Driving Mechanism of SOL Plasma Flow and Effects on the Divertor Performance in JT-60U
N.Asakura 1), H.Takenaga 1), S.Sakurai 1), G.D.Porter 2), T.D.Rognlien 2), M.E.Rensink 2), O.Naito 1), K.Shimizu 1), K.Itami 1), S.Higashijima 1), T.Nakano 1), H.Kubo 1), Y.Koide 1), Y.Sakamoto 1), T.Takizuka 1), A.V.Chankin 1), S.Konoshima 1), and the JT-60 Team
1) Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
2) Lawrence Livermore National Laboratory, P.O.Box 808, Livermore, CA 94550, USA
Abstract.
The measurement s of the SOL flow and plasma profiles both at the high-field-side (HFS) and low-field-side (LFS), for the first time, identified the SOL flow pattern and its driving mechanism. Flow reversal was found near the HFS and LFS separatrix of the main plasma for the ion ∇B drift direction towards the divertor. Radial profiles of the SOL flow were similar to those calculated numerically using the UEDGE code with the plasma drifts included although Mach numbers in measurements were greater than those obtained numerically. Particle fluxes towards the HFS and LFS divertors produced by the parallel SOL flow and ErxB drift flow were evaluat ed.The part icle flux for the case of intense gas puff and divertor pump (puff and pump) was investigated, and it was found that both the Mach number and collisionality were enhanced, in particular, at HFS. Drift flux in the private flux region was also evaluated, and important physics issues for the divertor design and operation, such as in-out asymmetries of the heat and particle fluxes, and control of impurity ions were investigated.