Improvements in tokamak transport have recently been obtained in a variety of operational modes through the formation of transport barriers, or good confinement radial zones. Here global nonlinear three‐dimensional toroidal gyrokinetic simulation is used to study three effects that are linearly stabilizing and may cause the formation of transport barriers, namely, sheared toroidal rotation, reversed magnetic shear, and peaked density profiles. The effect of toroidal shear flow on ion heat diffusivity is found to be relatively weak compared to mixing‐length expectations based on linear calculations. In contrast, it is found that weak or negative magnetic shear (s<1/2) in combination with a peaked density profile relative to the temperature profile greatly suppresses ion‐temperature‐gradient‐driven turbulence in the central region of global nonlinear simulations. Similar features are seen experimentally in reversed magnetic shear tokamak plasmas. There is some nonlocal penetration (∼20–30ρi) of the turbulence into the subcritical core region.
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Research Article|
May 01 1996
Radially global gyrokinetic simulation studies of transport barriers
S. E. Parker;
S. E. Parker
Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543‐0451
Department of Physics, University of California, Los Angeles, Los Angeles, California 90024
Advanced Computing Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
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H. E. Mynick;
H. E. Mynick
Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543‐0451
Department of Physics, University of California, Los Angeles, Los Angeles, California 90024
Advanced Computing Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
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M. Artun;
M. Artun
Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543‐0451
Department of Physics, University of California, Los Angeles, Los Angeles, California 90024
Advanced Computing Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
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J. C. Cummings;
J. C. Cummings
Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543‐0451
Department of Physics, University of California, Los Angeles, Los Angeles, California 90024
Advanced Computing Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
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V. Decyk;
V. Decyk
Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543‐0451
Department of Physics, University of California, Los Angeles, Los Angeles, California 90024
Advanced Computing Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
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J. V. Kepner;
J. V. Kepner
Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543‐0451
Department of Physics, University of California, Los Angeles, Los Angeles, California 90024
Advanced Computing Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
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W. W. Lee;
W. W. Lee
Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543‐0451
Department of Physics, University of California, Los Angeles, Los Angeles, California 90024
Advanced Computing Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
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W. M. Tang
W. M. Tang
Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543‐0451
Department of Physics, University of California, Los Angeles, Los Angeles, California 90024
Advanced Computing Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
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Phys. Plasmas 3, 1959–1966 (1996)
Article history
Received:
November 09 1995
Accepted:
February 01 1996
Citation
S. E. Parker, H. E. Mynick, M. Artun, J. C. Cummings, V. Decyk, J. V. Kepner, W. W. Lee, W. M. Tang; Radially global gyrokinetic simulation studies of transport barriers. Phys. Plasmas 1 May 1996; 3 (5): 1959–1966. https://doi.org/10.1063/1.871992
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