I am trying to understand current theories about why pulsars glitch. I have come across two explanations that I'm assuming are complementary, but which I am having trouble reconciling.
- The inner super-fluid component is spinning faster than the crust. Occasionally, the two briefly bind, during which angular momentum is transferred.
This is based off of the wikepedia entry for "glitch". Intuitively, I picture this as two aligned globes, with one spinning inside the other.
- The inner super-fluid component contains "currents", which rotate around vortex lines. Normally, these vortex lines are pinned to the crust. However, when a large number of them unpin at once, they transfer some of the angular momentum of the currents to the crust, resulting in a glitch.
This is coming from the vortex creep model (summary in section 2). It is hard to describe in words how I picture this, so I include a picture below. I imagine these spikes are vortex lines... And that's about as far as I can get.
Are these vortex lines rotating with the crust, so that a given "packet" of super-fluid both has a global rotation about the star's axis of rotation, as well as a local rotation around the vortex line? If so, is this global rotation what is referenced in explanation 1)?
Additionally, 1) seems to be reliant on the crust and super-fluid component being unbound from each-other (except during a glitch), but 2) seems to imply that the components are bound to each other (except during a glitch). This seems to imply a fundamental misinterpretation of something on my part, but I'm not sure exactly what.