Measurements of the nonlinear beat wave produced by the interaction of counterpropagating Alfvén waves

Abstract

Plasma turbulence has been shown to play a critical role in many astrophysical and space environments. In the solar corona and solar wind, this turbulence involves the nonlinear interaction of kinetic Alfv en waves. In the Earth's magnetosphere, the turbulence is dominated by inertial Alfv en wave collisions. Observations of these wave-wave interactions in space and in laboratory plasma environments have shown that, in addition to the nonlinear cascade of energy to small scales, the interaction also produces nonlinear beat waves that have a frequency defined by f 6 3 ¼ jf 1 6f 2 j. Although the temporal behavior of the beat wave has been well documented, this paper presents the first detailed analysis of the spatial structure of the nonlinearly generated beat wave. V C 2016 AIP Publishing LLC. [http://dx.

Nonlinear energy transfer and current sheet development in localized Alfvén wavepacket collisions in the strong turbulence limit

“…2012, 2013; Drake et al. 2013, 2014, 2016). The derivation of the analytical solution was possible using the idealized initial conditions of two overlapping, perpendicularly polarized Alfvén waves in a periodic geometry, and solving for the nonlinear evolution of the system.…”

Revisiting a Classic: The Parker–moffatt Problem

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Turbulence in heliospheric plasmas

“…Early research on incompressible magnetohydrodynamics (MHD) turbulence in the 1960s (Iroshnikov, 1963;Kraichnan, 1965) suggested that nonlinear interactions between counterpropagating Alfvén waves-or Alfvén wave collisions-support the turbulent cascade of energy from large to small scales. Following significant previous studies on weak incompressible MHD turbulence (Sridhar and Goldreich, 1994;Montgomery and Matthaeus, 1995;Ng and Bhattacharjee, 1996;Galtier et al, 2000), recent work has elucidated the mechanism of energy transfer in Alfvén wave collisions in the weakly nonlinear limit by computing an asymptotic analytical solution using incompressible MHD , verifying that solution using nonlinear gyrokinetic simulations in the MHD limit of perpendicular scales larger than the Larmor radius, k ⊥ ρ i 1 , and confirming the results experimentally in the laboratory Drake et al, , 2014Drake et al, , 2016. The derivation of the analytical solution was possible using the idealized initial conditions of two overlapping, perpendicularly polarized Alfvén waves in a periodic geometry, and solving for the nonlinear evolution of the system.…”