Establishment of strong velocity shear and plasma density profile modification with associated low frequency fluctuations

Strong shear of azimuthal plasma rotation velocity and a large density profile modification from a hollow to peaked profiles were successfully obtained in a cylindrical magnetized plasma, using voltage biased electrodes. The shear region and density profiles could be finely controlled by changing the voltage biased position as well as by the magnetic field configurations. A low frequency (<4 kHz) density oscillation was identified as a drift wave type: propagation in the electron diamagnetic direction with a rigid rotation (Mach number M∼−1 at the edge), opposite to the direction of the edge plasma rotation with M∼1.