Mode Composition Shapes Magnetic Anisotropy in Solar Wind Turbulence

Fuente: arXiv
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Auteurs principaux: Zhao, Siqi, Yan, Huirong, Liu, Terry Z., Hou, Chuanpeng
Format: Preprint
Publié: 2025
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author Zhao, Siqi
Yan, Huirong
Liu, Terry Z.
Hou, Chuanpeng
author_facet Zhao, Siqi
Yan, Huirong
Liu, Terry Z.
Hou, Chuanpeng
contents Turbulence is a ubiquitous process that transfers energy across many spatial and temporal scales, thereby influencing particle transport and heating. Recent progress has improved our understanding of the anisotropy of turbulence with respect to the mean magnetic field; however, its exact form and implications for magnetic topology and energy transfer remain unclear. In this study, we investigate the nature of magnetic anisotropy in compressible magnetohydrodynamic (MHD) turbulence within low-$β$ solar wind using measurements from the Cluster spacecraft. By decomposing small-amplitude fluctuations into Alfvén and compressible modes, we reveal that magnetic anisotropy is largely mode dependent: Alfvenic fluctuations are broadly distributed in propagation angle, whereas compressible fluctuations are concentrated near the quasi-parallel (slab) direction, a feature closely linked to collisionless damping of compressible modes. For $β\rightarrow0$, compressible modes become dominant within the slab component at smaller scales. These findings advance our understanding of magnetic anisotropy in solar wind turbulence and offer a new perspective on the three-dimensional turbulence cascade, with broad implications for particle transport, acceleration, and magnetic reconnection.
format Preprint
id arxiv_https___arxiv_org_abs_2510_25636
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Mode Composition Shapes Magnetic Anisotropy in Solar Wind Turbulence
Zhao, Siqi
Yan, Huirong
Liu, Terry Z.
Hou, Chuanpeng
Solar and Stellar Astrophysics
Plasma Physics
Space Physics
Turbulence is a ubiquitous process that transfers energy across many spatial and temporal scales, thereby influencing particle transport and heating. Recent progress has improved our understanding of the anisotropy of turbulence with respect to the mean magnetic field; however, its exact form and implications for magnetic topology and energy transfer remain unclear. In this study, we investigate the nature of magnetic anisotropy in compressible magnetohydrodynamic (MHD) turbulence within low-$β$ solar wind using measurements from the Cluster spacecraft. By decomposing small-amplitude fluctuations into Alfvén and compressible modes, we reveal that magnetic anisotropy is largely mode dependent: Alfvenic fluctuations are broadly distributed in propagation angle, whereas compressible fluctuations are concentrated near the quasi-parallel (slab) direction, a feature closely linked to collisionless damping of compressible modes. For $β\rightarrow0$, compressible modes become dominant within the slab component at smaller scales. These findings advance our understanding of magnetic anisotropy in solar wind turbulence and offer a new perspective on the three-dimensional turbulence cascade, with broad implications for particle transport, acceleration, and magnetic reconnection.
title Mode Composition Shapes Magnetic Anisotropy in Solar Wind Turbulence
topic Solar and Stellar Astrophysics
Plasma Physics
Space Physics
url https://arxiv.org/abs/2510.25636