Kinetic theory of rf current drive and helicity injection

Journal Article · Wed Jan 01 00:00:00 EST 1992 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860437· OSTI ID:5393866

Mett, R R ^[1]

---

1. Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)

Current drive and helicity injection by plasma waves are examined with the use of kinetic theory. The Vlasov equation yields a general current drive formula that contains resonant and nonresonant (ponderomotivelike) contributions. Standard quasilinear current drive is described by the former, while helicity current drive may be contained in the latter. Since direct analytical comparison of the sizes of the two terms is, in general, difficult, a new approach is taken. Solution of the drift-kinetic equation shows that the standard Landau damping/transit time magnetic pumping quasilinear diffusion coefficient is the only contribution to steady-state current drive to leading order in {epsilon}={rho}{sub L}/{ital l}, where {rho}{sub L} is the Larmor radius and {ital l} is the inhomogeneity scale length. All nonresonant contributions, including the helicity, appear at higher order, after averages are taken over a flux surface, over azimuth, and over time. Consequently, at wave frequencies well below the electron cyclotron frequency, a wave helicity flux perpendicular to the magnetic field does {ital not} influence the parallel motion of electrons to leading order and therefore will not drive a significant current. Any current associated with a wave helicity flux is then either ion current (and thus inefficient) or electron current stemming from effects not included in the drift-kinetic treatment, such as cyclotron, collisional, or nonlinear (i.e., not quasilinear).

• DOE Contract Number: FG05-80ET53088
• OSTI ID: 5393866
• Journal Information: Physics of Fluids B; (United States), Vol. 4:1; ISSN 0899-8221
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CURRENT-DRIVE HEATING
KINETIC EQUATIONS
INHOMOGENEOUS PLASMA
HELICITY
CYCLOTRON FREQUENCY
ELECTROMAGNETIC FIELDS
LANDAU DAMPING
LARMOR RADIUS
MAGNETOHYDRODYNAMICS
PLASMA DENSITY
PLASMA DRIFT
PLASMA WAVES
WAVE PROPAGATION
DAMPING
ELECTRIC HEATING
EQUATIONS
FLUID MECHANICS
HEATING
HYDRODYNAMICS
JOULE HEATING
MECHANICS
PARTICLE PROPERTIES
PLASMA
PLASMA HEATING
RESISTANCE HEATING
700340* - Plasma Waves
Oscillations
& Instabilities- (1992-)
700330 - Plasma Kinetics
Transport
& Impurities- (1992-)