2021/10/21 by Trevor A. Bowen, Samuel T. Badman, Bowen, Trevor A. +23 · 1 citation
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #Amplitude #Astrophysics #Classical mechanics #Computational physics #FOS: Physical sciences #Geomagnetism and Paleomagnetism Studies #Ionosphere and magnetosphere dynamics #Magnetic field #Magnetohydrodynamic turbulence #Magnetohydrodynamics #Mechanics #Nonlinear system #Physics #Plasma Physics (physics.plasm-ph) #Quantum electrodynamics #Quantum mechanics #Solar and Space Plasma Dynamics #Solar and Stellar Astrophysics (astro-ph.SR) #Space Physics (physics.space-ph) #Turbulence #astro-ph.SR #physics.plasm-ph #physics.space-ph
paper · pdf · doi:10.48550/arxiv.2110.11454
arxiv created 2021/10/21 · openalex publication_date 2021/10/21 · arxiv updated 2021/10/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Turbulent magnetic field fluctuations observed in the solar wind often maintain a constant magnitude condition accompanied by spherically polarized velocity fluctuations; these signatures are characteristic of large-amplitude Alfvén waves. Nonlinear energy transfer in Alfvénic turbulence is typically considered in the small-amplitude limit where the constant magnitude condition may be neglected; in contrast, nonlinear energy transfer in the large-amplitude limit remains relatively unstudied. We develop a method to analyze finite-amplitude turbulence through studying fluctuations as constant magnitude rotations in the stationary wave (de Hoffmann-Teller) frame, which reveals that signatures of finite-amplitude effects exist deep into the MHD range. While the dominant fluctuations are consistent with spherically-polarized large-amplitude Alfvén waves, the subdominant mode is relatively compressible. Signatures of nonlinear interaction between the finite-amplitude spherically polarized mode with the subdominant population reveal highly aligned transverse components. In theoretical models of Alfvénic turbulence, alignment is thought to reduce nonlinearity; our observations require that alignment is sufficient to either reduce shear nonlinearity such that non-Alfvénic interactions may be responsible for energy transfer in spherically polarized states, or that counter-propagating fluctuations maintain anomalous coherence, which is a predicted signature of reflection-driven turbulence.