Effects of orbit squeezing on ion transport in the banana regime in tokamaks
- Oak Ridge National Lab., TN (United States)
- 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
- Resource Relation:
- Other Information: PBD: Feb 1992
- Country of Publication:
- United States
- Language:
- English
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