The rapid inward diffusion of cold ions in tokamaks and their effect on ion transport

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

DOI:https://doi.org/10.1063/1.859465· OSTI ID:6800029

Ware, A A ^[1]

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1. Institute for Fusion Studies 61500, The University of Texas at Austin, Austin, Texas 78712 (USA)

The observed increase with density of the density asymmetry caused by the centrifugal force of toroidal motion in the PDX tokamak ({ital Plasma} {ital Physics} {ital and} {ital Controlled} {ital Nuclear} {ital Fusion} {ital Research} (IAEA, Vienna, 1981), Vol. 1, p. 665), which is contrary to conventional theory, is explained by the presence of an excess of low-energy ions with 10%--15% concentration. The prime source being recycling, it is shown that low-energy ions undergo rapid inward diffusion (too rapid to thermalize with the outward diffusing energetic ions) because of the combined effects of large {nu}{sub PA}, electrostatic diffusion, and negative {ital E}{sub {ital r}} and {partial derivative}{ital T}{sub {ital i}}/{partial derivative}{ital r}. The presence of the low-energy ions alters dramatically the predictions of neoclassical theory and many hydrogen and impurity ion transport phenomena now have simple explanations.

• DOE Contract Number: FG05-80ET53088
• OSTI ID: 6800029
• Journal Information: Physics of Fluids B; (USA), Journal Name: Physics of Fluids B; (USA) Journal Issue: 6 Vol. 2:6; 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
700103* -- Fusion Energy-- Plasma Research-- Kinetics
ANNULAR SPACE
ASYMMETRY
CHARGED PARTICLES
CLOSED CONFIGURATIONS
CLOSED PLASMA DEVICES
COLD PLASMA
CONFIGURATION
DIFFUSION
ELECTRON DENSITY
ELECTRON TEMPERATURE
ELECTROSTATICS
ELEMENTS
HYDROGEN
IMPURITIES
INELASTIC SCATTERING
ION DRIFT
IONS
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC FIELDS
NONMETALS
PDX DEVICES
PLASMA
PLASMA DIAGNOSTICS
SCATTERING
SPACE
THERMONUCLEAR DEVICES
THOMSON SCATTERING
TOKAMAK DEVICES
TOROIDAL CONFIGURATION