The role of turbulence and winding in the development of large-scale, strong magnetic fields in long-lived remnants of binary neutron star mergers

• DOI: 10.48550/arxiv.2307.04837
• Publication Date: 2023-01-01
• Authors: Ricard Aguilera-M...; Carlos Palenzuela; F. Carrasco; Daniele Viganò
• Keywords: High Energy Astrophysical Phenomena (astro-ph.HE); FOS: Physical sciences; General Relativity and Quantum Cosmology (gr-qc); Astrophysics - High Energy Astrophysical Phenomena; General Relativity and Quantum Cosmology

We perform a long and accurate Large-Eddy Simulation of binary neutron star merger, following the newly formed remnant up to 110 milliseconds. The combination high-order schemes, high-resolution gradient subgrid-scale model allow us have among highest effective resolutions ever achieved. Our results show that, although magnetic fields are strongly amplified by Kelvin-Helmholtz instability, they coherent only over very short spatial scales until t \gtrsim 30 ms. Around that time, winding becomes more efficient leading linear growth toroidal component slowly ordering field axisymmetric, large scales. poloidal starts grow at small much later times 90 ms, in way compatible with magneto-rotational instability. No strong large-scale or jet is produced timescales spanned our simulation, there an helicoidal structure gradually developing late times. highlight soon after merger topology always dominated structures, complex distribution meridional plane highly turbulent perturbations. Thus, starting purely dipolar before largely inconsistent outcomes realistic evolution. Finally, we confirm universality evolved topology, even when different confined outermost layers each star.