Three-dimensional stability of drift vortices

Journal Article · Mon Jan 01 04:00:00 EST 1996 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.871842· OSTI ID:253471

Akerstedt, H O ^[1]; Nycander, J; Pavlenko, V P ^[2]

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1. Division of Fluid Mechanics, Lulea University of Technology, 951 87 Lulea (Sweden)
2. Department of Technology, Euratom-NFR Fusion Association, Uppsala University, Box 534, 751 21 Uppsala (Sweden)

The three-dimensional stability of drift vortices that are two-dimensionally stable in the framework of the Hasegawa{endash}Mima equation is studied. The three-dimensionality is caused by a coupling of the vortex to ion-acoustic waves that propagate along the magnetic field. It is concluded that this coupling does not significantly destabilize the vortex. A general stability criterion is derived that guarantees stability if the ratio between the parallel wave number {ital k} and the azimuthal mode number {ital m} is large enough. It is also found that no instability exists in the limit {ital k}{implies}0 if the potential vorticity is a strictly decreasing function of {ital r}. Such profiles are typical for vortices that are two-dimensionally stable. Some particular profiles where the potential vorticity vanishes outside some radius are also examined. In one case an instability with {ital m}=1 is found, but a numerical solution of the eigenvalue problem shows that the maximum growth rate is very small, three orders of magnitude smaller than the angular velocity of the vortex flow. {copyright} {ital 1996 American Institute of Physics.}

• OSTI ID: 253471
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 1 Vol. 3; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DISPERSION RELATIONS
DRIFT INSTABILITY
INSTABILITY GROWTH RATES
ION ACOUSTIC WAVES
PLASMA MICROINSTABILITIES
TURBULENCE
VARIATIONAL METHODS
VORTICES