Informal Pizza Seminar

Magnetic Field Evolution by Hall and Thermomagnetic Effects in Neutron Stars

Andrew Cumming

McGill

Recent years have seen tremendous advances in our understanding of neutron stars, which are a much more varied population than previously known. Particularly exciting has been the discovery of "magnetars", highly magnetized neutron stars with 10¹⁵ G magnetic fields. In this talk, I discuss review some of the physical processes leading to magnetic field evolution. In the crust of the star, the ions are held fixed in a solid lattice, giving rise to Hall effects on macroscopic lengthscales. Dissipation of magnetic energy in a turbulent "Hall cascade" may powers the X-ray and gamma-ray emission from magnetars. In neutron stars in binary systems, heated by the addition of matter from a companion star, thermomagnetic effects possibly lead to growth of magnetic field, and an intimate connection between the thermal and magnetic histories of the star. I discuss the physics of these processes, the current state of theoretical modelling, and the connection to observations.