Effects of orbit squeezing on ion transport in the banana regime in tokamaks

Journal Article · Sat Aug 01 04:00:00 EDT 1992 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860170· OSTI ID:7034304

Shaing, K C ^[1]; Hazeltine, R D ^[2]

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1. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
2. Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712 (United States)

It is shown that ion transport in the banana regime in tokamaks is reduced in the presence of a strong shear in the radial electric field {ital E}{sub {ital r}} , as is often observed in the edge region. For simplicity, the ordering with {rho}{sub {ital pi}}{vert bar}{ital d} ln {ital E}{sub {ital r} }/{ital dr}{vert bar} {much gt} 1 but {ital c}{vert bar}{ital E}{sub {ital r}}{vert bar}/{ital B}{sub {ital p}v}{sub {ital ti}} {lt} 1 is adopted. Here, {rho}{sub {ital pi}} is the ion poloidal gyroradius, {ital B}{sub {ital p}} is the poloidal magnetic field strength, {ital v}{sub {ital ti}} is the ion thermal speed, and {ital c} is the speed of light. A kinetic transport theory similar to those for bumpy tori and stellarators is developed to show that the ion thermal conductivity {chi}{sub {ital i}} is reduced by a factor of roughly {ital S}{sup {minus}3/2}, where {ital S} = 1 {minus} ({rho}{sub {ital pi} }{ital d} ln {ital E}{sub {ital r}} /{ital dr})({ital cE}{sub {ital r}} {ital B}{sub {ital pv}}{sub {ital ti}}). The result reflects more than simple orbit squeezing: The fraction of trapped ions is also modified by {ital S}.

• DOE Contract Number: AC05-84OR21400; FG05-80ET53088
• OSTI ID: 7034304
• Journal Information: Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 4:8; ISSN PFBPE; ISSN 0899-8221
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700310 -- Plasma Confinement-- (1992-)
700330* -- Plasma Kinetics
Transport
& Impurities-- (1992-)
BANANA REGIME
CHARGED PARTICLES
CLOSED PLASMA DEVICES
EQUATIONS
IONS
KINETIC EQUATIONS
ORBITS
PHYSICAL PROPERTIES
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TRANSPORT THEORY
TRAPPING