Effects of ion diamagnetic flow on shock formation in poloidally rotating tokamak plasmas

When the poloidal ion diamagnetic flow is of the order of the E×B drift velocity, it significantly affects the shock formation in a poloidally rotating tokamak plasma. (Here, E is the electric field and B is the magnetic field.) The poloidal density variation in both linear and shock regimes can be weakened if the poloidal ion diamagnetic flow tends to cancel the poloidal E×B flow. The magnitude of the density variation is not symmetric with respect to the direction of the E×B poloidal rotation. The resonant condition at which strong shock occurs is also modified dramatically by the diamagnetic flow. For some cases, the poloidal density variation inside the bifurcated electric field layer in the L–H transition [Phys. Rev. Lett. 42, 1408 (1982)] may not be large enough to significantly modify the plasma viscosity obtained by neglecting the compressibility effects.