Suppression of the m=1 internal kink instability in a high-. beta. /sub J/ tokamak

Journal Article · Tue May 01 00:00:00 EDT 1979 · Sov. J. Plasma Phys. (Engl. Transl.); (United States)

OSTI ID:5670555

Krymskii, A M; Mikhailovskii, A B

The m=1 internal kink mode in a tokamak with a high ..beta../sub J/ and a small current gradient is analyzed. In contrast with earlier work, effects of order (..beta../sub J/a/R)/sup 4/ and (..beta../sub j/a/R)/sup 6/, where a and R are the minor and major radii of the torus. A sufficient condition for stability with respect to the m=1 mode is derived. This condition shows that this mode can in principle be suppressed for an arbitrary value of the radius a/sub O/, defined by q (a/sub O/) =1 (q is the safety factor). This is true for an arbitrarily small value of a/a/sub asteriskprime/ where a/sub asterisk/ is the liner radius. For an approximately flat current profile, an increase in the plasma pressure (to ..beta../sub J/approx. =R/a) does not degrade the stability with respect to the m=1 internal kink mode, in fact, the stability is improved. This result is derived for a plasma model with a fixed boundary, but it is believed that it remains valid for a plasma with a free boundary, where the internal modes may have unstable surface modes. In this case, the problem of maintaining stability should reduce to that of stabilizing the surface modes (for example, by feedback) and to the maintenance of a favorable current profile, i.e., one which is approximately flat.

• Research Organization: I. V. Kurchatov Institute of Atomic Energy, Moscow
• OSTI ID: 5670555
• Journal Information: Sov. J. Plasma Phys. (Engl. Transl.); (United States), Vol. 5:3
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
HIGH-BETA PLASMA
KINK INSTABILITY
TOKAMAK DEVICES
BALLOONING INSTABILITY
MAGNETIC SURFACES
MAGNETOHYDRODYNAMICS
TOROIDAL CONFIGURATION
ANNULAR SPACE
CLOSED PLASMA DEVICES
CONFIGURATION
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
MAGNETIC FIELD CONFIGURATIONS
MECHANICS
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
THERMONUCLEAR DEVICES
700107* - Fusion Energy- Plasma Research- Instabilities