Evolution of the surface magnetic field of rotating proto-neutron stars

TL;DR

This study investigates how the surface magnetic field of proto-neutron stars evolves immediately after core collapse, revealing complex magnetic structures influenced by accretion processes through axisymmetric simulations.

Contribution

It provides the first detailed analysis of the magnetic field topology and angular spectra evolution on proto-neutron stars using self-consistent axisymmetric simulations.

Findings

Magnetic field structures are complex with high power at intermediate angular scales.

Accretion of low-magnetization material effectively buries the magnetic field.

Results inform long-term magnetothermal evolution studies.

Abstract

We study the evolution of the field on the surface of proto-neutron stars in the immediate aftermath of stellar core collapse by analyzing the results of self-consistent, axisymmetric simulations of the cores of rapidly rotating high-mass stars. To this end, we compare the field topology and the angular spectra of the poloidal and toroidal field components over a time of about one seconds for cores. Both components are characterized by a complex geometry with high power at intermediate angular scales. The structure is mostly the result of the accretion of magnetic flux embedded in the matter falling through the turbulent post-shock layer onto the PNS. Our results may help to guide further studies of the long-term magnetothermal evolution of proto-neutron stars. We find that the accretion of stellar progenitor layers endowed with low or null magnetization bury the magnetic field on the PNS surface very effectively.