skip to main content

Title: Observation of dust torus with poloidal rotation in direct current glow discharge plasma

Observation of dust cloud rotation in parallel-plate DC glow discharge plasma is reported here. The experiments are carried out at high pressures (∼130 Pa) with a metallic ring placed on the lower electrode (cathode). The dust cloud rotates poloidally in the vertical plane near the cathode surface. This structure is continuous toroidally. Absence of magnetic field rules out the possibility of E × B induced ion flow as the cause of dust rotation. The dust rotational structures exist even with water cooled cathode. Therefore, temperature gradient driven mechanisms, such as thermophoretic force, thermal creep flow, and free convection cannot be causing the observed dust rotation. Langmuir probe measurement reveals the existence of a sharp density gradient near the location of the rotating dust cloud. The gradient in the density, giving rise to a gradient in the ion drag force, has been identified as the principal cause behind the rotation of dust particles.
Authors:
; ; ; ; ;  [1]
  1. Institute for Plasma Research, Gandhinagar 382428 (India)
Publication Date:
OSTI Identifier:
22408268
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CATHODES; CREEP; DENSITY; DIRECT CURRENT; DRAG; DUSTS; ELECTRIC FIELDS; GLOW DISCHARGES; IONS; LANGMUIR PROBE; MAGNETIC FIELDS; NATURAL CONVECTION; PARTICLES; PLASMA; PRESSURE RANGE MEGA PA 10-100; ROTATING PLASMA; TEMPERATURE GRADIENTS; TOROIDAL CONFIGURATION