Suppression of magnetic islands by energetic ions in toroidal plasmas

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

DOI:https://doi.org/10.1063/1.859452· OSTI ID:6682192

Hegna, C C; Bhattacharjee, A ^[1]

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1. Department of Applied Physics, Columbia University, New York, New York 10027 (USA)

This is a study of the effect of an energetic ion population injected from a neutral beam source on the nonlinear stability of magnetic islands. A kinetic theory is used to obtain the island current, which includes previously known modifications resulting from bootstrap currents and resistive interchanges. The island current thus obtained is used in an asymptotic treatment of the perturbed Ampere's law, which yields an evolution equation for the island width. It is shown that the island width saturates at a very small amplitude in tokamaks (with {Delta}{prime}{gt}0) when the energetic ion density profile peaks just outside the rational surface. Energetic ions can also be used to modify the island width in three-dimensional equilibria. It is found that in stellarator equilibria with large vacuum islands, energetic ions can be injected to reduce the widths of equilibrium islands.

• DOE Contract Number: FG02-86ER53222
• OSTI ID: 6682192
• Journal Information: Physics of Fluids B; (USA), Journal Name: Physics of Fluids B; (USA) Vol. 2:8; ISSN 0899-8221; ISSN PFBPE
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107* -- Fusion Energy-- Plasma Research-- Instabilities
ANNULAR SPACE
ASYMPTOTIC SOLUTIONS
ATOMIC BEAM SOURCES
BOOTSTRAP CURRENT
CHARGED PARTICLES
CLOSED CONFIGURATIONS
CONFIGURATION
CURRENTS
ELECTRIC CURRENTS
FLUTE INSTABILITY
INHIBITION
INSTABILITY
IONS
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC ISLANDS
NEUTRAL BEAM SOURCES
NONLINEAR PROBLEMS
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
SPACE
STABILITY
TOROIDAL CONFIGURATION