Two corrections to the drift-wave kinetic equation in the
context of zonal-flow physics
Authors: D.E. Ruiz, E.L. Shi, I.Y. Dodin
Abstract: The drive-wave (DW) kinetic equation, that is
commonly used in studies of zonal flows (ZF), excludes the
exchange of enstrophy between DW and ZF and also effects beyond
the geometrical-optics limit. Using the quasilinear approximation
of the generalized Hasegawa-Mima model, we propose a modified
theory that accounts for these effects within a wave kinetic
equation (WKE) of the Wigner-Moyal type, which is commonly known
in quantum mechanics. In the geometrical-optics limit, this theory
features additional terms beyond the traditional WKE that ensure
exact conservation of the total enstrophy and energy in the DW-ZF
system. Numerical simulations are presented to illustrate the
importance of these additional terms. The proposed theory can be
viewed as a reformulation of the second-order cumulant expansion
(also known as the CE2) in a more intuitive manner, namely in
terms of canonical phase-space variables.
Submitted to: Physics of Plasmas
Download PPPL-5284 (pdf
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