Subgrid modelling of MRI-driven turbulence in differentially rotating neutron stars
Subgrid modelling of MRI-driven turbulence in differentially rotating neutron stars
Following a binary neutron star (BNS) merger, the transient remnant is often a fast-spinning, differentially rotating, magnetised hypermassive neutron star (HMNS). This object is prone to the magnetorotational instability (MRI) which drives magnetohydrodynamic turbulence that significantly influences the HMNS global dynamics. A key consequence of turbulence is the outward transport of angular momentum which impacts the remnant's stability and lifetime. Most numerical simulations of BNS mergers are unable to resolve the MRI due to its inherently small wavelength. To overcome this limitation, subgrid models have been proposed to capture the effects of unresolved small-scale physics in terms of large-scale quantities. We present the first implementation of our MHD-Instability-Induced Turbulence (MInIT) model in global Newtonian simulations of MRI-sensitive, differentially rotating, magnetised neutron stars. Here, we show that by adding the corresponding turbulent stress tensors to the momentum equation, MInIT successfully reproduces the angular momentum transport in neutron stars driven by small-scale turbulence.
MHD, Stars: neutron, Turbulence
Miravet-Tenés, Miquel
398b0819-ed3a-44a3-aa0c-4e912ebcbef1
Obergaulinger, Martin
80357175-4198-4c4a-a56f-c871fda605f0
Cerdá-Durán, Pablo
59f3ca65-5d00-45b9-86e9-d6a2f45cca7d
Font, José A.
51ef41b0-fdb1-4473-87f9-ebad097c5e3b
Ruiz, Milton
f9b63951-e9bd-4ea5-ba65-8df048a80978
23 December 2025
Miravet-Tenés, Miquel
398b0819-ed3a-44a3-aa0c-4e912ebcbef1
Obergaulinger, Martin
80357175-4198-4c4a-a56f-c871fda605f0
Cerdá-Durán, Pablo
59f3ca65-5d00-45b9-86e9-d6a2f45cca7d
Font, José A.
51ef41b0-fdb1-4473-87f9-ebad097c5e3b
Ruiz, Milton
f9b63951-e9bd-4ea5-ba65-8df048a80978
Miravet-Tenés, Miquel, Obergaulinger, Martin, Cerdá-Durán, Pablo, Font, José A. and Ruiz, Milton
(2025)
Subgrid modelling of MRI-driven turbulence in differentially rotating neutron stars.
Monthly Notice of the Royal Astronomical Society, 545 (3), [staf2081].
(doi:10.1093/mnras/staf2081).
Abstract
Following a binary neutron star (BNS) merger, the transient remnant is often a fast-spinning, differentially rotating, magnetised hypermassive neutron star (HMNS). This object is prone to the magnetorotational instability (MRI) which drives magnetohydrodynamic turbulence that significantly influences the HMNS global dynamics. A key consequence of turbulence is the outward transport of angular momentum which impacts the remnant's stability and lifetime. Most numerical simulations of BNS mergers are unable to resolve the MRI due to its inherently small wavelength. To overcome this limitation, subgrid models have been proposed to capture the effects of unresolved small-scale physics in terms of large-scale quantities. We present the first implementation of our MHD-Instability-Induced Turbulence (MInIT) model in global Newtonian simulations of MRI-sensitive, differentially rotating, magnetised neutron stars. Here, we show that by adding the corresponding turbulent stress tensors to the momentum equation, MInIT successfully reproduces the angular momentum transport in neutron stars driven by small-scale turbulence.
Text
staf2081
- Version of Record
More information
Accepted/In Press date: 18 November 2025
e-pub ahead of print date: 22 November 2025
Published date: 23 December 2025
Additional Information:
Publisher Copyright:
© The Author(s) 2025. Published by Oxford University Press on behalf of Royal Astronomical Society.
Keywords:
MHD, Stars: neutron, Turbulence
Identifiers
Local EPrints ID: 508834
URI: http://eprints.soton.ac.uk/id/eprint/508834
PURE UUID: ddba899b-25eb-4334-b4ca-5c2377e147ed
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Date deposited: 04 Feb 2026 17:44
Last modified: 05 Feb 2026 03:13
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Contributors
Author:
Miquel Miravet-Tenés
Author:
Martin Obergaulinger
Author:
Pablo Cerdá-Durán
Author:
José A. Font
Author:
Milton Ruiz
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