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

Abstract

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.

Initial Trial of Plasma Mass Separation by Crossed Electric and Magnetic Fields

“…4(c), which is consistent with the previous result. 14,19,20) On the other hand, the Xe rotation velocity in Fig. 5(a) saturated at V 8 {10 ¼ 180 V and then it decayed with the further increase in V 8 {10 , while V f and I is in Figs.…”

The invalidity of a Mach probe model

“…There is no such established model for unmagnetized probe measurements. Nevertheless many recent authors, and specifically three recent papers in the Physics of Plasmas [2][3][4] have used the convenient but unjustified formulas from Hudis and Lidsky. 5 The purpose of this comment is to emphasize again that the model of Hudis and Lidsky is unfounded in physics and cannot be expected to give a reliable calibration of Mach probes other than by coincidence.…”

Radial current and rotation profile tailoring in highly ionized linear plasma devices

“…There could conceivably be other orders contributing to the ∆v (2,0) θ in Eq. (14), but the resulting flows do not contribute to the leading-order current or particle flux anyway.…”

“…v in the inertial part of Eq. (14). There could conceivably be other orders contributing to the ∆v (2,0) θ in Eq.…”

“…Achieving this control is a nontrivial problem; past efforts in linear devices have often focused on biasable annular end electrodes. [13][14][15][16][17][18][19][20] Another possibility is through waves, or stationary perturbations, 21 though this has not yet been attempted experimentally.…”