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Main Authors: Lazarian, A., Hu, Yue, Pogosyan, D.
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2512.19816
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author Lazarian, A.
Hu, Yue
Pogosyan, D.
author_facet Lazarian, A.
Hu, Yue
Pogosyan, D.
contents Super-Alfvénic turbulence is widespread in astrophysical environments, including molecular clouds and the diffuse plasma of galaxy clusters. At large scales, magnetic fields play only a minor dynamical role; however, for sufficiently extended turbulent cascades, the motions transition into the MHD regime at a characteristic scale $l_A$. We introduce a new diagnostic based on the structure functions of the gradient directions, which can be obtained directly from spectroscopic and synchrotron intensity observations. We demonstrate that the new measure robustly recovers the transition scale $l_A$. Building on this result, we propose a generalized expression that replaces the traditional Davis-Chandrasekhar-Fermi (DCF) method for estimating magnetic field strength in the super-Alfvénic regime, where the DCF approach fails. We further show how the magnetization and magnetic field strength of diffuse media, such as the intracluster medium, can be inferred using synchrotron intensity maps. Our theoretical predictions are validated through numerical simulations.
format Preprint
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institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Obtaining Magnetization of Super-Alfvénic Turbulence with the Structure Functions of Gradient Directions
Lazarian, A.
Hu, Yue
Pogosyan, D.
Astrophysics of Galaxies
Super-Alfvénic turbulence is widespread in astrophysical environments, including molecular clouds and the diffuse plasma of galaxy clusters. At large scales, magnetic fields play only a minor dynamical role; however, for sufficiently extended turbulent cascades, the motions transition into the MHD regime at a characteristic scale $l_A$. We introduce a new diagnostic based on the structure functions of the gradient directions, which can be obtained directly from spectroscopic and synchrotron intensity observations. We demonstrate that the new measure robustly recovers the transition scale $l_A$. Building on this result, we propose a generalized expression that replaces the traditional Davis-Chandrasekhar-Fermi (DCF) method for estimating magnetic field strength in the super-Alfvénic regime, where the DCF approach fails. We further show how the magnetization and magnetic field strength of diffuse media, such as the intracluster medium, can be inferred using synchrotron intensity maps. Our theoretical predictions are validated through numerical simulations.
title Obtaining Magnetization of Super-Alfvénic Turbulence with the Structure Functions of Gradient Directions
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2512.19816