Low-frequency current drive and helicity injection

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

DOI:https://doi.org/10.1063/1.859241· OSTI ID:7000204

Chan, V S; Miller, R L; Ohkawa, T ^[1]

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1. General Atomics, San Diego, California 92138-5608 (USA)

For {omega}{much lt}{Omega}{sub {ital i}}, where {Omega}{sub {ital i}} is the ion cyclotron frequency, circularly polarized waves can drive current far exceeding the current resulting from linearly polarized waves. Further, the efficiency can be independent of plasma density. In some cases, this circular polarization may be interpreted in terms of helicity injection. For tokamak applications, where the wavenumber in the toroidal direction is a real quantity, wave helicity is injected only with finite {ital E}{sub {ital z}} waves, where {ital z} is the direction of the static magnetic field. The Alfven waves are possible current drive candidates but, in the cylindrical model considered, the compressional wave is weakly damped because {ital E}{sub {ital z}} =0, while the shear Alfven wave is totally absorbed at the surface because of finite {ital E}{sub {ital z}}. A mixture of the two modes is shown to drive an oscillatory surface current even though the efficiency is high and independent of density. A more promising current drive candidate is a fast wave that propagates to the plasma interior and is damped by the minority cyclotron resonance. Near the minority mode conversion region, the fast wave is left-handed circularly polarized and it has a small but finite {ital E}{sub {ital z}} component at high electron temperatures. The current drive efficiency, although not as high as that of the Alfven wave, is still good and independent of density, making it attractive for fusion reactors.

• DOE Contract Number: AC03-89ER53277
• OSTI ID: 7000204
• Journal Information: Physics of Fluids B; (USA), Journal Name: Physics of Fluids B; (USA) Vol. 2:5; ISSN 0899-8221; ISSN PFBPE
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700101* -- Fusion Energy-- Plasma Research-- Confinement
Heating
& Production
700108 -- Fusion Energy-- Plasma Research-- Wave Phenomena
ABSORPTION
ALFVEN WAVES
BREMSSTRAHLUNG
CLOSED PLASMA DEVICES
COLD PLASMA
COLLISIONAL PLASMA
CONVERSION
CURRENT-DRIVE HEATING
CYCLOTRON RADIATION
CYLINDERS
DAMPING
EFFICIENCY
ELECTRIC FIELDS
ELECTRIC HEATING
ELECTROMAGNETIC RADIATION
ELECTRON TEMPERATURE
ENERGY CONVERSION
FLUID MECHANICS
FREQUENCY DEPENDENCE
HEATING
HELICITY
HIGH-FREQUENCY HEATING
HYDRODYNAMICS
HYDROMAGNETIC WAVES
ICR HEATING
JOULE HEATING
MAGNETOHYDRODYNAMICS
MECHANICS
OSCILLATION MODES
PARTICLE PROPERTIES
PLASMA
PLASMA DENSITY
PLASMA HEATING
POLARIZATION
RADIATIONS
RESISTANCE HEATING
SHEAR
SLABS
STEADY-STATE CONDITIONS
THERMONUCLEAR DEVICES
TOKAMAK DEVICES