Magnetic Flux Emergence in Binary Neutron Star Remnants

TL;DR

This study uses high-resolution simulations to investigate magnetic flux emergence in binary neutron star remnants, revealing that only extremely strong magnetic fields can emerge due to buoyant instabilities, impacting jet formation.

Contribution

It demonstrates that magnetic buoyant instabilities require magnetic fields exceeding 10^{17} G to emerge, limiting mechanisms for jet production in neutron star merger remnants.

Findings

Magnetic buoyant instabilities occur only for fields >10^{17} G.

Typical fields around 10^{16} G are dominated by hydrodynamics.

Remnants are stable against hydrodynamic convection, constraining jet formation mechanisms.

Abstract

Using high-resolution AthenaK simulations of a twisted toroidal flux tube, we study the flux emergence of magnetic structures in the shear layer of a hot massive neutron star typical of a binary neutron star remnant. High-resolution simulations demonstrate that magnetic buoyant instabilities allow for emergence only for extremely large magnetic fields significantly exceeding $10^{17}~\mathrm{G}$, and more typical fields around $10^{16}~\mathrm{G}$ are instead dominated by hydrodynamic effects. Because merger remnants tend to be stable against hydrodynamic convection, our work places strong limitations on the mechanisms by which massive binary neutron star remnants can produce the magnetically-driven outflows needed to power jets.