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Superbanana and superbanana plateau transport in finite aspect ratio tokamaks with broken symmetry

Part of: Focus on Fusion

Published online by Cambridge University Press:  05 December 2014

K. C. Shaing Open the ORCID record for K. C. Shaing [Opens in a new window]
K. C. Shaing*
Affiliation:
Institute for Space and Plasma Sciences, National Cheng Kung University, Tainan 70101, Taiwan Engineering Physics Department, University of Wisconsin, Madison 53706, WI, USA
*
†Email address for correspondence: [email protected]
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Abstract

Superbanana and superbanana plateau transport processes are critical to plasma confinement in tokamaks with broken symmetry. The transport is caused by the superbanana resonance, which occurs at a pitch angle that makes the toroidal drift speed vanish, i.e. the tips of the superbananas. The physics consequences of the resonance on the symmetry breaking induced toroidal momentum damping and on the energetic alpha particle transport have been demonstrated using large aspect ratio expansion. Here, the existing theory for the superbanana and superbanana plateau transport is extended for finite aspect ratio tokamaks with broken symmetry. The effects of finite plasma β, and magnetic field shear are naturally included. Here, β is the ratio of the thermal plasma pressure to the magnetic field pressure. The explicit expressions for the transport fluxes in these regimes in terms of the equilibrium quantities are presented. It is shown that the main effects are to modify the resonance function G(k) and the expression for the pitch angle parameter k in the existing theory.

Type
Research Article
Information
Journal of Plasma Physics , Volume 81 , Issue 2 , April 2015 , 905810203
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Copyright
Copyright © Cambridge University Press 2014 

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