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Title: Collisional damping for ion temperature gradient mode driven zonal flow

Abstract

Zonal flow helps reduce and control the level of ion temperature gradient turbulence in a tokamak. The collisional damping of zonal flow has been estimated by Hinton and Rosenbluth (HR) in the large radial wavelength limit. Their calculation shows that the damping of zonal flow is closely related to the frequency response of neoclassical polarization of the plasma. Based on a variational principle, HR calculated the neoclassical polarization in the low and high collisionality limits. A new approach, based on an eigenfunction expansion of the collision operator, is employed to evaluate the neoclassical polarization and the zonal flow residual for arbitrary collisionality. An analytical expression for the temporal behavior of the zonal flow is also given showing that the damping rate tends to be somewhat slower than previously thought. These results are expected to be useful extensions of the original HR collisional work that can provide an effective benchmark for numerical codes for all regimes of collisionality.

Authors:
; ;  [1]
  1. Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
Publication Date:
OSTI Identifier:
20974874
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 3; Other Information: DOI: 10.1063/1.2536297; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BENCHMARKS; COLLISIONS; DAMPING; EIGENFUNCTIONS; ELECTRON TEMPERATURE; ION TEMPERATURE; NEOCLASSICAL TRANSPORT THEORY; PLASMA; PLASMA CONFINEMENT; PLASMA INSTABILITY; POLARIZATION; TEMPERATURE GRADIENTS; TOKAMAK DEVICES; TURBULENCE; VARIATIONAL METHODS

Citation Formats

Xiao Yong, Catto, Peter J., and Molvig, Kim. Collisional damping for ion temperature gradient mode driven zonal flow. United States: N. p., 2007. Web. doi:10.1063/1.2536297.
Xiao Yong, Catto, Peter J., & Molvig, Kim. Collisional damping for ion temperature gradient mode driven zonal flow. United States. doi:10.1063/1.2536297.
Xiao Yong, Catto, Peter J., and Molvig, Kim. Thu . "Collisional damping for ion temperature gradient mode driven zonal flow". United States. doi:10.1063/1.2536297.
@article{osti_20974874,
title = {Collisional damping for ion temperature gradient mode driven zonal flow},
author = {Xiao Yong and Catto, Peter J. and Molvig, Kim},
abstractNote = {Zonal flow helps reduce and control the level of ion temperature gradient turbulence in a tokamak. The collisional damping of zonal flow has been estimated by Hinton and Rosenbluth (HR) in the large radial wavelength limit. Their calculation shows that the damping of zonal flow is closely related to the frequency response of neoclassical polarization of the plasma. Based on a variational principle, HR calculated the neoclassical polarization in the low and high collisionality limits. A new approach, based on an eigenfunction expansion of the collision operator, is employed to evaluate the neoclassical polarization and the zonal flow residual for arbitrary collisionality. An analytical expression for the temporal behavior of the zonal flow is also given showing that the damping rate tends to be somewhat slower than previously thought. These results are expected to be useful extensions of the original HR collisional work that can provide an effective benchmark for numerical codes for all regimes of collisionality.},
doi = {10.1063/1.2536297},
journal = {Physics of Plasmas},
number = 3,
volume = 14,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
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