Turbulent Dynamo Action in Binary Neutron Star Mergers

Fuente: arXiv
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Main Authors: Gutiérrez, Eduardo M., Radice, David, Fields, Jacob, Stone, James M.
Format: Preprint
Published: 2026
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author Gutiérrez, Eduardo M.
Radice, David
Fields, Jacob
Stone, James M.
author_facet Gutiérrez, Eduardo M.
Radice, David
Fields, Jacob
Stone, James M.
contents Binary neutron star mergers are expected to generate intense magnetic fields that power relativistic and non-relativistic outflows and shape their multimessenger signatures. These fields likely arise from the turbulent amplification of initially weak magnetic fields during the merger, particularly via the Kelvin-Helmholtz instability at the collisional interface between the stars. While previous studies have shown efficient amplification to magnetar-level strengths, the degree of large-scale coherence of the resulting field remains uncertain. We present general-relativistic, dynamical spacetime, magnetohydrodynamic simulations following the evolution of initially weak, pulsar-like magnetic fields in a binary neutron star merger. We find rapid magnetic field growth at small scales with clear signatures of small-scale turbulent dynamo action. At the highest resolutions, we additionally observe the emergence of coherent magnetic structures on larger scales. Our results imply that strong, ordered magnetic fields may be present immediately after merger, with important implications for the subsequent evolution of the remnant and its observable electromagnetic and gravitational-wave signals.
format Preprint
id arxiv_https___arxiv_org_abs_2601_20953
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Turbulent Dynamo Action in Binary Neutron Star Mergers
Gutiérrez, Eduardo M.
Radice, David
Fields, Jacob
Stone, James M.
High Energy Astrophysical Phenomena
General Relativity and Quantum Cosmology
Binary neutron star mergers are expected to generate intense magnetic fields that power relativistic and non-relativistic outflows and shape their multimessenger signatures. These fields likely arise from the turbulent amplification of initially weak magnetic fields during the merger, particularly via the Kelvin-Helmholtz instability at the collisional interface between the stars. While previous studies have shown efficient amplification to magnetar-level strengths, the degree of large-scale coherence of the resulting field remains uncertain. We present general-relativistic, dynamical spacetime, magnetohydrodynamic simulations following the evolution of initially weak, pulsar-like magnetic fields in a binary neutron star merger. We find rapid magnetic field growth at small scales with clear signatures of small-scale turbulent dynamo action. At the highest resolutions, we additionally observe the emergence of coherent magnetic structures on larger scales. Our results imply that strong, ordered magnetic fields may be present immediately after merger, with important implications for the subsequent evolution of the remnant and its observable electromagnetic and gravitational-wave signals.
title Turbulent Dynamo Action in Binary Neutron Star Mergers
topic High Energy Astrophysical Phenomena
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2601.20953