Magnetar Crusts: Matter at $10^{15}$ Gauss

TL;DR

This paper explores how extremely strong magnetic fields in magnetar crusts transform their electrical properties, making them insulators and filamentary crystals, which affects current dissipation.

Contribution

It reveals that at magnetar magnetic field strengths, the crust becomes a transverse insulator and filamentary crystal, with conductivity inversely proportional to the square of the magnetic field.

Findings

Crust becomes a transverse insulator at high magnetic fields.

Transverse conductivity scales as 1/B^2.

Enhanced dissipation of crustal currents at high fields.

Abstract

In this work we find that the at the high polar magnetic fields of magnetars, $B \sim 10^{14-15}$ G, the outermost crust ($\rho < 10^7$ gm/cc) of the star can become a transverse insulator and a filamentary crystal along the field direction. Also, the transverse conductivity in the crust goes inversely as the square of polar magnetic field (as $1/B^2$). At these high fields the transverse crustal currents associated with the polar magnetic field can then dissipate more effectively via Ohm's law.