April 15-17

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Abstracts

Author: Yao Zhou
Requested Type: Pre-Selected Invited
Submitted: 2019-02-19 20:28:30

Co-authors: Hongxuan Zhu, I. Y. Dodin

Contact Info:
Princeton Plasma Physics Laboratory
100 Stellarator Rd
Princeton, NJ   08543-0
United States

Abstract Text:
The dynamics of the radial envelope of a weak coherent drift wave can be approximately described by a nonlinear Schrödinger equation, which emerges as a limit of the modified Hasegawa-Mima equation. The nonlinear Schrödinger equation has well-known soliton solutions, and its modulational instability can naturally generate solitary structures. We show that the same mechanism can produce solitary zonal structures in the modified Hasegawa-Mima equation as well, but only when the amplitude of the primary drift wave is relatively small. Otherwise, stationary zonal structures are formed instead. Similarly, we show that incoherent drift-waves with beam-like spectra can also be modulationally unstable to the formation of solitary or stationary zonal structures, depending on the beam intensity. We model these drift waves as quantumlike particles ("driftons") within a phase-space (Wigner-Moyal) formulation, which depicts the solitary zonal structures as self-trapping drifton condensates. Quantumlike effects, such as diffraction, are essential to these condensates; hence, they cannot be described by wave-kinetic models that are based on the ray approximation. (arXiv:1902.06870)

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