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

Technical Report · Sat Feb 01 04:00:00 EST 1992

OSTI ID:10133681

Shaing, K C ^[1]; Hazeltine, R D ^[2]

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1. Oak Ridge National Lab., TN (United States)
2. Texas Univ., Austin, TX (United States). Inst. for Fusion Studies

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 E{sub r}, as is often observed in the edge region. For simplicity, the ordering with {rho}{sub pi}{vert_bar}d ln E{sub r}/dr{vert_bar} {much_gt} 1 but c{vert_bar}E{sub r}{vert_bar}/B{sub p}{upsilon}{sub ti} < 1 is adopted. Here, {rho}{sub pi} is the ion poloidal gyroradius, B{sub p} is the poloidal magnetic field strength, {upsilon}{sub ti} is the ion thermal speed, and 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 i} is reduced by a factor of roughly S{sup {minus}3/2}, where S = 1 {minus} ({rho}{sub pi}d ln E{sub r}/dr)(cE{sub r}/B{sub {rho}}{upsilon}{sub ti}). The result reflects more than simple orbit squeezing: the fraction of trapped ions is also modified by S.

• Research Organization: Texas Univ., Austin, TX (United States). Inst. for Fusion Studies
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG05-80ET53088; AC05-84OR21400
• OSTI ID: 10133681
• Report Number(s): DOE/ET/53088--539; IFSR--539; ON: DE92010548
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700330
BANANA REGIME
CHARGED-PARTICLE TRANSPORT
DISTRIBUTION FUNCTIONS
KINETIC EQUATIONS
MAGNETIC FIELDS
ORBITS
PLASMA KINETICS, TRANSPORT, AND IMPURITIES
THERMAL CONDUCTIVITY
TOKAMAK DEVICES