Effects of supersonic beam and pellet injection on edge electric field andplasma rotation in HL-1M

Experimental measurements of edge electric field and plasma rotation have b een carried out on both of scrape-off layer (SOL) and the boundary region o f HL-1M for Ohmic, Supersonic Beam Injection (SBI) and Multi-shot Pellet In jection (MPI) with a Mach/Langmuir probe array. The radial profiles of the toroidal flow Mach number M, the poloidal flow rotation velocity V-pol and the electric field E-r are measured during experiments of MPI and SBI respe ctively. The effects of supersonic beam injection and multi-shot pellet inj ection on the edge electric field, plasma rotation and fluctuation have bee n observed. The results show that the change of the radial electric field E -r is generated and becomes more negative at the tokamak plasma edge and th e sheared poloidal flow relates to the reduction in fluctuation level. Duri ng SBI and MPI, poloidal rotation velocities of 3.8 km/s and 10 km/s in the electron diamagnetic direction are measured, respectively. From the measur ements we also obtain radial electric fields of -8 and -14 kV/m, respective ly in the plasma edge region. It appears that the poloidal velocity is main ly dominated by the E x B drift. (C) 1999 Elsevier Science B.V. All. rights reserved.