The perpendicular velocity (v⊥) of turbulence is measured by means of a hopping poloidal correlation reflectometer diagnostic for the study of turbulence rotation in the plasma edge region in Wendelstein 7-X. An elliptic approximation (EA) model is applied for calculating the space-time correlation in the edge region. The v⊥ profile is compared in the high-ι (edge ι ≈ 1.2) and limiter (edge ι < 1) configurations. It is found that the v⊥ gradient is inversely proportional to the heating power in the high-ι configuration, which could be attributed to the turbulence activities in the plasma edge. In the limiter configuration, the v⊥ spike is observed near the island boundary, which is corresponded to the plasma current crash. In the standard configuration (edge ι ≈ 1), the v⊥ profile in the island region distributes as a function of the perpendicular separation. With increasing of the plasma current, the island enlarges the size as is referred from the v⊥ scope, accompanying with steepening of the v⊥ gradient at the boundary of the island.
Comparison of L-H transition measurements with physics models