Turbulence Mode Decomposition and Anisotropy in Magnetically Dominated Collisionless Plasmas

Fuente: arXiv
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Main Authors: Sebastian, Samuel T., Xu, Siyao, Hu, Yue, Comisso, Luca, Das, Saikat, Nättilä, Joonas
Format: Preprint
Published: 2026
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author Sebastian, Samuel T.
Xu, Siyao
Hu, Yue
Comisso, Luca
Das, Saikat
Nättilä, Joonas
author_facet Sebastian, Samuel T.
Xu, Siyao
Hu, Yue
Comisso, Luca
Das, Saikat
Nättilä, Joonas
contents We use the 3D fully kinetic simulation to study different turbulence modes and turbulence anisotropy of relativistic turbulence in magnetically dominated collisionless plasmas. We extend the method developed by Cho & Lazarian (2002) for decomposing non-relativistic magnetohydrodynamic (MHD) turbulence into Alfvén, fast, and slow modes to the regime of collisionless plasmas. We find that Alfvén and slow modes are anisotropic, following the Goldreich & Sridhar (1995) scaling, while fast modes are isotropic. We observe a larger kinetic energy fraction of fast modes compared to that in the non-relativistic MHD turbulence, suggesting a stronger coupling of Alfvén and fast modes in relativistic magnetized turbulence in collisionless plasmas. We further examine the dynamic alignment and find a weaker scale dependence of the alignment angle than previously proposed. The dominant thermal fluctuations in the kinetic range can cause flattening of the turbulent velocity structure function and weakening of the turbulence anisotropy and dynamic alignment near the kinetic scales.
format Preprint
id arxiv_https___arxiv_org_abs_2604_20963
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Turbulence Mode Decomposition and Anisotropy in Magnetically Dominated Collisionless Plasmas
Sebastian, Samuel T.
Xu, Siyao
Hu, Yue
Comisso, Luca
Das, Saikat
Nättilä, Joonas
Plasma Physics
High Energy Astrophysical Phenomena
We use the 3D fully kinetic simulation to study different turbulence modes and turbulence anisotropy of relativistic turbulence in magnetically dominated collisionless plasmas. We extend the method developed by Cho & Lazarian (2002) for decomposing non-relativistic magnetohydrodynamic (MHD) turbulence into Alfvén, fast, and slow modes to the regime of collisionless plasmas. We find that Alfvén and slow modes are anisotropic, following the Goldreich & Sridhar (1995) scaling, while fast modes are isotropic. We observe a larger kinetic energy fraction of fast modes compared to that in the non-relativistic MHD turbulence, suggesting a stronger coupling of Alfvén and fast modes in relativistic magnetized turbulence in collisionless plasmas. We further examine the dynamic alignment and find a weaker scale dependence of the alignment angle than previously proposed. The dominant thermal fluctuations in the kinetic range can cause flattening of the turbulent velocity structure function and weakening of the turbulence anisotropy and dynamic alignment near the kinetic scales.
title Turbulence Mode Decomposition and Anisotropy in Magnetically Dominated Collisionless Plasmas
topic Plasma Physics
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2604.20963