Drift waves enstrophy, zonal flow, and nonlinear evolution of the modulational instability

Journal Article · Mon Jan 11 00:00:00 EST 2021 · Physics of Plasmas

DOI:https://doi.org/10.1063/5.0031301· OSTI ID:1849550

Krasheninnikov, S. I.  ^[1]; Smolyakov, A. I.  ^[2]; Zhang, Yanzeng  ^[1]; Chapurin, O.  ^[2]

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1. Univ. of California, San Diego, La Jolla, CA (United States). Dept. of Mechanical and Aerospace Engineering
2. Univ. of Saskatchewan, Saskatoon, SK (Canada). Dept. of Physics and Engineering Physics

The interaction of the drift wave (DW) turbulence and zonal flow (ZF) is investigated with the modified Hasegawa–Mima equation taking into account the backreaction of ZF velocity on DW turbulence. It is shown that the y-averaged enstrophy of DW turbulence and the velocity of ZF are intrinsically related. By utilizing this feature, a nonlinear stage of DW modulational instability is considered within the framework of the wave kinetic equation. It is shown that in this approximation, the nonlinear stage of the modulational instability results in the collapsing solutions, accompanied by the “wave breaking” phenomenon. Numerical simulations based on the Hasegawa–Mima equation show that for a weak DW turbulence, $\tilde{\Phi }=(e\tilde{\phi }/T_e)\hspace{0.17em}(L_n/{\rho }_s)⪝1$, the collapsing-like features on both ZF and y-averaged enstrophy of DW turbulence decay in time and then re-emerge again at different locations. For the case of a strong DW turbulence, $\tilde{\Phi }>1$, where nonlinear interactions of DW harmonics dominate, stable spatial structures of ZF and y-averaged enstrophy of DW turbulence emerge.

• Research Organization: Univ. of California, San Diego, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: FG02-04ER54739
• OSTI ID: 1849550
• Journal Information: Physics of Plasmas, Vol. 28, Issue 1; ISSN 1070-664X
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
Physics
Plasma waves
Modulational instability
Turbulent flows
Plasma flows