Shear viscosity in magnetized neutron star crust

TL;DR

This paper calculates the electron shear viscosity in the magnetized crust of neutron stars, considering various states of nuclei and magnetic effects, providing detailed coefficients and analyzing their dependence on magnetic fields.

Contribution

It introduces a comprehensive model for shear viscosity in magnetized neutron star crusts, including five viscosity coefficients and their magnetic field dependence.

Findings

Viscosity coefficients depend on magnetic field strength.

The model accounts for gaseous, liquid, and solid nuclear states.

Magnetic fields significantly influence shear viscosity behavior.

Abstract

The electron shear viscosity due to Coulomb scattering of degenerate electrons by atomic nuclei throughout a magnetized neutron star crust is calculated. The theory is based on the shear viscosity coefficient calculated neglecting magnetic fields but taking into account gaseous, liquid and solid states of atomic nuclei, multiphonon scattering processes, and finite sizes of the nuclei albeit neglecting the effects of electron band structure. The effects of strong magnetic fields are included in the relaxation time approximation with the effective electron relaxation time taken from the field-free theory. The viscosity in a magnetized matter is described by five shear viscosity coefficients. They are calculated and their dependence on the magnetic field and other parameters of dense matter is analyzed. Possible applications and open problems are outlined.