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Title: Ion temperature gradient instability at sub-Larmor radius scales with non-zero ballooning angle

Abstract

Linear gyro-kinetic stability calculations predict unstable toroidal ion temperature gradient modes (ITGs) with normalised poloidal wave vectors well above one (k{sub {theta}}{rho}{sub i}>1) for standard tokamak parameters with adiabatic electron response. These modes have a maximum amplitude at a poloidal angle {theta} that is shifted away from the low field side ({theta}{ne}0). The physical mechanism is clarified through the use of a fluid model. It is shown that the shift of the mode away from the low field side reduces the effective drift frequency which allows for the instability to develop. Numerical tests using the gyro-kinetic model confirm this physical mechanism. Furthermore, it is shown that modes localized away from the low field side can be important also for k{sub {theta}}{rho}{sub i}<1 close to the threshold of the ITG. In fact, modes with maximum amplitude at {theta}{ne}0 can exist for normalised temperature gradient lengths below the threshold of the ITG obtained for the case with the maximum at {theta}=0.

Authors:
; ;  [1];  [2];  [3]
  1. Physics Department, University of Bayreuth, Universitaetsstrasse 30 Bayreuth (Germany)
  2. Aix-Marseille Universite, CNRS, PIIM UMR 7345, 13397 Marseille (France)
  3. Max Planck Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstrasse 2, 85748 Garching (Germany)
Publication Date:
OSTI Identifier:
22113416
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 20; Journal Issue: 2; Other Information: (c) 2013 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AMPLITUDES; BALLOONING INSTABILITY; CONFINEMENT; ELECTRON TEMPERATURE; FLUIDS; ION TEMPERATURE; LARMOR RADIUS; NUMERICAL ANALYSIS; PLASMA; STABILITY; TEMPERATURE GRADIENTS; TOKAMAK DEVICES

Citation Formats

Migliano, P., Hornsby, W. A., Peeters, A. G., Camenen, Y., and Casson, F. J. Ion temperature gradient instability at sub-Larmor radius scales with non-zero ballooning angle. United States: N. p., 2013. Web. doi:10.1063/1.4789856.
Migliano, P., Hornsby, W. A., Peeters, A. G., Camenen, Y., & Casson, F. J. Ion temperature gradient instability at sub-Larmor radius scales with non-zero ballooning angle. United States. https://doi.org/10.1063/1.4789856
Migliano, P., Hornsby, W. A., Peeters, A. G., Camenen, Y., and Casson, F. J. 2013. "Ion temperature gradient instability at sub-Larmor radius scales with non-zero ballooning angle". United States. https://doi.org/10.1063/1.4789856.
@article{osti_22113416,
title = {Ion temperature gradient instability at sub-Larmor radius scales with non-zero ballooning angle},
author = {Migliano, P. and Hornsby, W. A. and Peeters, A. G. and Camenen, Y. and Casson, F. J.},
abstractNote = {Linear gyro-kinetic stability calculations predict unstable toroidal ion temperature gradient modes (ITGs) with normalised poloidal wave vectors well above one (k{sub {theta}}{rho}{sub i}>1) for standard tokamak parameters with adiabatic electron response. These modes have a maximum amplitude at a poloidal angle {theta} that is shifted away from the low field side ({theta}{ne}0). The physical mechanism is clarified through the use of a fluid model. It is shown that the shift of the mode away from the low field side reduces the effective drift frequency which allows for the instability to develop. Numerical tests using the gyro-kinetic model confirm this physical mechanism. Furthermore, it is shown that modes localized away from the low field side can be important also for k{sub {theta}}{rho}{sub i}<1 close to the threshold of the ITG. In fact, modes with maximum amplitude at {theta}{ne}0 can exist for normalised temperature gradient lengths below the threshold of the ITG obtained for the case with the maximum at {theta}=0.},
doi = {10.1063/1.4789856},
url = {https://www.osti.gov/biblio/22113416}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 2,
volume = 20,
place = {United States},
year = {Fri Feb 15 00:00:00 EST 2013},
month = {Fri Feb 15 00:00:00 EST 2013}
}