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| Zonal Jet Creation from Secondary Instability of Drift Waves for Plasma Edge Turbulence |
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Citation： |
Di QI,Andrew J. MAJDA.Zonal Jet Creation from Secondary Instability of Drift Waves for Plasma Edge Turbulence[J].Chinese Annals of Mathematics B,2019,40(6):869~890 |
| Page view： 625
Net amount： 558 |
Authors： |
Di QI; Andrew J. MAJDA |
Foundation： |
This work was supported by the Office of Naval Research
through MURI (No.N00014-16-1-2161). |
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| Abstract： |
A new strategy is presented to explain the creation and persistence
of zonal flows widely observed in plasma edge turbulence. The core
physics in the edge regime of the magnetic-fusion tokamaks can be
described qualitatively by the one-state modified Hasegawa-Mima (MHM
for short) model, which creates enhanced zonal flows and more physically
relevant features in comparison with the familiar
Charney-Hasegawa-Mima (CHM for short) model for both plasma and
geophysical flows. The generation mechanism of zonal jets is
displayed from the secondary instability analysis via nonlinear
interactions with a background base state. Strong exponential growth
in the zonal modes is induced due to a non-zonal drift wave base
state in the MHM model, while stabilizing damping effect is shown
with a zonal flow base state. Together with the selective decay
effect from the dissipation, the secondary instability offers a
complete characterization of the convergence process to the purely
zonal structure. Direct numerical simulations with and without
dissipation are carried out to confirm the instability theory. It
shows clearly the emergence of a dominant zonal flow from pure
non-zonal drift waves with small perturbation in the initial
configuration. In comparison, the CHM model does not create
instability in the zonal modes and usually converges to homogeneous
turbulence. |
Keywords： |
Zonal flow generation, Drift wave turbulence, Secondary instability, Modified Hasegawa-Mima model |
Classification： |
76F06, 35Q60, 76E25 |
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