Velocity-shear-induced ion-cyclotron turbulence: Laboratory identification and space applications

Journal Article · Thu Jun 01 04:00:00 EDT 1995 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.871214· OSTI ID:165307

Koepke, M E; Amatucci, W E; Carroll, III, J J; Gavrishchaka, V ^[1]; Ganguli, G ^[2]

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1. Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States)
2. Plasma Physics Division, Code 6700, Naval Research Laboratory, Washington, D.C. 20375 (United States)

Laboratory measurements are reported that identify a new class of plasma oscillation driven by the inhomogeneity in wave energy density caused by transverse-velocity shear [Ganguli {ital et} {ital al}., Phys. Fluids {bold 31}, 823 (1988)]. The experiments concentrate on a branch of oscillation in the ion-cyclotron range of frequencies that results from the coupling of the magnetic-field-aligned current and the inhomogeneous dc electric field localized in a layer thicker than the ion gyroradius. The observed transition between the well-known current-driven electrostatic ion-cyclotron mode and this inhomogeneous energy--density-driven mode is related to the ratio of the azimuthal and axial Doppler shifts. The mode characteristics associated with the two instabilities have significantly different properties. For conditions of large transverse-velocity shear, turbulence is generated with a broadband, spiky spectrum around the ion-cyclotron frequency at small values of the magnetic-field-aligned current. The experimental identification is reinforced with numerical results from a nonlocal eigenvalue condition. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

• OSTI ID: 165307
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 6 Vol. 2; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CYCLOTRON FREQUENCY
DOPPLER EFFECT
EARTH MAGNETOSPHERE
ENERGY DENSITY
ION CYCLOTRON-RESONANCE
IONOSPHERE
PLASMA INSTABILITY
Q DEVICES
TURBULENCE