Ponderomotive stabilization of external kink modes in tokamaks

Journal Article · Mon Feb 01 04:00:00 EST 1988 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.866866· OSTI ID:5504398

D'Ippolito, D A

It is shown that external kink modes in tokamaks can be stabilized by applied radio frequency (rf) waves in the ion cyclotron range of frequencies. This stabilization results from the work done by the plasma against the ponderomotive force exerted by the rf field. For a strongly evanescent surface field (such as the near field of an ion Bernstein wave coupler), the ponderomotive layer is confined to the vicinity of the plasma surface and, if sufficiently strong, influences kink stability in the same way as a close-fitting conducting wall. This effect is illustrated by deriving an analytic condition for stabilizing a single (m,n) mode in the low-beta straight tokamak model by means of a cylindrically symmetric E/sub parallel/ rf field. The effects of poloidally or toroidally nonuniform rf fields are examined in a two-mode coupling perturbation analysis. This stabilization mechanism may be useful in extending the beta limit of ion-Bernstein-wave-heated tokamaks against both ideal and resistive modes.

• Research Organization: Science Applications International Corporation, Plasma Research Institute, 1515 Walnut Street, Boulder, Colorado 80302
• OSTI ID: 5504398
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 31:2; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107* -- Fusion Energy-- Plasma Research-- Instabilities
CLOSED PLASMA DEVICES
CONTROL
ELECTRIC POTENTIAL
HIGH-BETA PLASMA
INSTABILITY
KINK INSTABILITY
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
STABILIZATION
SURFACES
THERMONUCLEAR DEVICES
TOKAMAK DEVICES