Rotating neutron stars without light cylinders

TL;DR

This paper introduces a class of neutron star magnetospheres that are differentially rotating without light cylinders, do not produce winds, and do not spin down, challenging traditional models of pulsar magnetospheres.

Contribution

The study presents a new class of neutron star magnetosphere solutions with differential rotation that lack light cylinders and wind generation, expanding understanding of neutron star magnetic configurations.

Findings

Existence of magnetospheres without light cylinders.

Magnetospheres with differential rotation decreasing as 1/r.

Critical spin parameter beyond which light cylinder and wind appear.

Abstract

We find a class of twisted and differentially rotating neutron star magnetospheres that do not have a light cylinder, generate no wind and thus do not spin-down. The magnetosphere is composed of embedded differentially rotating flux surfaces, with the angular velocity decreasing as $\Omega \propto 1/r$ (equivalently, becoming smaller at the foot-points closer to the axis of rotation). For each given North-South self-similar twist profile there is a set of self-similar angular velocity profiles (limited from above) with a "smooth", dipolar-like magnetic field structure extending to infinity. For spin parameters larger than some critical value, the light cylinder appears, magnetosphere opens up, and the wind is generated.