Thursday, November 7, 2019, 11:00am to 12:00pm
Magnetic coupling between the crust and the core of neutron stars.
What do magnetic fields look like inside neutron stars? We do not know; since reliable
observational constraints are few, the theorists' imagination can run wild. For example,
some very popular models assume that the field is confined to the crust and does not
penetrate into the core at all!!
In this talk I will give two insights. First comes from a spectacular magnetospheric disturbance
observed recently during a glitch in Vela. I argue that the disturbance is a result of a quake, during which crustal
seismic waves penetrated into the magnetosphere and the core of the pulsar. I will show evidence for
a strong magnetic crust-core coupling, which points with certainty to a strong poloidal field at the
crust-core interface, and indicates (with less certainty) that the magnetic stresses are strengthened
by superconductivity in the core. The second insight comes from magnetar quasi-periodic oscillations.
The models that included the crust-core coupling, have been predicting that many of the QPOs should
be strongly transient and intermittent. Recently, these predictions have been confirmed by Miller et al.