Experiments on vortex dynamics in pure electron plasmas

Journal Article · Fri Jun 01 04:00:00 EDT 1990 · Physics of Fluids B; (USA)

DOI:https://doi.org/10.1063/1.859556· OSTI ID:6804812

Driscoll, C F; Fine, K S ^[1]

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1. University of California at San Diego, La Jolla, California 92093 (USA)

Magnetically confined columns of electrons are excellent experimental manifestations of two-dimensional (2-D) vortices in an inviscid fluid. Surface charge perturbations on the electron column (diocotron modes) are equivalent to surface ripples on extended vortices; and unstable diocotron modes on hollow electron columns are examples of the Kelvin--Helmholtz instability. Experiments demonstrate that the stable and unstable modes are distinct and may coexist, having different frequencies and radial eigenfunctions. For azimuthal mode number {ital l}=1, an exponentially unstable mode is observed on hollow columns, in apparent contradiction to 2-D fluid theory. For {ital l}=2, a similar unstable mode is observed, consistent with fluid theory. These diocotron instabilities on hollow columns saturate with the formation of smaller vortex structures, and radial transport is determined by the nonlinear interaction of these secondary vortices. The vortex pairing instability has been observed for isolated, well-controlled vortices, and the instability is found to depend critically on the vortex separation distance.

• DOE Contract Number: FG03-85ER53199
• OSTI ID: 6804812
• Journal Information: Physics of Fluids B; (USA), Journal Name: Physics of Fluids B; (USA) Vol. 2:6; ISSN PFBPE; ISSN 0899-8221
• Country of Publication: United States
• Language: English

Related Subjects

640430* -- Fluid Physics-- Magnetohydrodynamics
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AZIMUTH
CONFINEMENT
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
HELMHOLTZ INSTABILITY
INSTABILITY
LEPTONS
MAGNETIC CONFINEMENT
PLASMA
PLASMA CONFINEMENT
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
TWO-DIMENSIONAL CALCULATIONS
VORTICES