Velocity-shear-driven drift waves with simultaneous azimuthal modes in a barium-ion Q-machine plasma

Journal Article · Sat Oct 01 04:00:00 EDT 2005 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2102747· OSTI ID:20702233

Kaneko, T; Reynolds, E W; Hatakeyama, R; Koepke, M E ^[1]

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1. Department of Electronic Engineering, Tohoku University, Sendai 980-8579 (Japan)

Low-frequency instabilities modified by a field-aligned flow velocity shear are investigated, where the shear is controlled using a concentrically three-segmented ion emitter in a modified double-ended Q-machine [T. Kaneko et al., Rev. Sci. Instrum. 73, 4218 (2002)]. When the barium-ion flow velocity shear is produced by applying different bias voltages to two of the three segments of the ion source, drift waves having azimuthal mode number m=1, 2, and 3 are observed to be excited simultaneously. It is found that the excitation-threshold value of the shear strength depends on the azimuthal mode number, as expected from a model based on kinetic theory, suggesting that the observations are explained by the competition between inverse electron Landau damping and shear-modified ion Landau damping.

• OSTI ID: 20702233
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 10 Vol. 12; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BARIUM IONS
DRIFT INSTABILITY
LANDAU DAMPING
PLASMA WAVES
SHEAR