Kostas Gourgouliatos' simulations explain magnetic hotspots
(3 June 2018)
Knots that form in the magnetic field lines of neutron stars early in their lifetime can be at the origin of magnetic hotspots that persist for millions of years. Together with Rainer Hollerbach, a colleague from Leeds University, Kostas used numerical simulations to model the evolution of the magnetic field.
They found out that the 3-dimensional nature of the neutron star's magnetic field was important: if the toroidal field carried more than half of the energy, variable spin speeds within the star would wind up and entangle the magnetic field, making it unstable. The resulting knots emerge from the star's surface, forming spots sometimes 200 times stronger than the poloidal field. The simulations shed light on some unusual pulsar behaviour, notably on magnetars that have dipole magnetic fields too weak to produce their observed radio outbursts. The research is published in the Astrophysical Journal.