Neoclassical poloidal and toroidal rotation in tokamaks

Journal Article · Thu Aug 01 00:00:00 EDT 1991 · Physics of Fluids B; (USA)

DOI:https://doi.org/10.1063/1.859671· OSTI ID:5604485

Kim, Y B; Diamond, P H; Groebner, R J ^[1]

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1. Department of Physics, University of California, San Diego, La Jolla, California 92093 (US)

Explicit expressions for the neoclassical poloidal and toroidal rotation speeds of primary ion and impurity species are derived via the Hirshman and Sigmar moment approach. The rotation speeds of the primary ion can be significantly different from those of impurities in various interesting cases. The rapid increase of impurity poloidal rotation in the edge region of H-mode discharges in tokamaks can be explained by a rapid steepening of the primary ion pressure gradient. Depending on ion collisionality, the poloidal rotation speed of the primary ions at the edge can be quite small and the flow direction may be opposite to that of the impurities. This may cast considerable doubts on current L to H bifurcation models based on primary ion poloidal rotation only. Also, the difference between the toroidal rotation velocities of primary ions and impurities is not negligible in various cases. In Ohmic plasmas, the parallel electric field induces a large impurity toroidal rotation close to the magnetic axis, which seems to agree with experimental observations. In the ion banana and plateau regime, there can be non-negligible disparities between primary ion and impurity toroidal rotation velocities due to the ion density and temperature gradients. Detailed analytic expressions for the primary ion and impurity rotation speeds are presented, and the methodology for generalization to the case of several impurity species is also presented for future numerical evaluation.

• OSTI ID: 5604485
• Journal Information: Physics of Fluids B; (USA), Vol. 3:8; ISSN 0899-8221
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
COLLISIONAL PLASMA
IMPURITIES
BANANA REGIME
EQUATIONS
IONS
JOULE HEATING
MOMENTS METHOD
PLATEAU REGIME
ROTATION
TOKAMAK DEVICES
TOROIDAL CONFIGURATION
ANNULAR SPACE
CHARGED PARTICLES
CLOSED CONFIGURATIONS
CLOSED PLASMA DEVICES
CONFIGURATION
ELECTRIC HEATING
HEATING
MAGNETIC FIELD CONFIGURATIONS
MOTION
PLASMA
PLASMA HEATING
RESISTANCE HEATING
SPACE
THERMONUCLEAR DEVICES
TRAPPING
700201* - Fusion Power Plant Technology- Blanket Engineering