Instability of Superfluid Flow in the Neutron Star Inner Crust

Understand

Pinning of superfluid vortices to the nuclear lattice of the inner crust of a neutron star supports a velocity difference between the superfluid and the solid as the star spins down.

• Under the Magnus force that arises on the vortex lattice, vortices undergo {\em vortex creep} through thermal activation or quantum tunneling.
• We examine the hydrodynamic stability of this situation.
• Vortex creep introduces two low-frequency modes, one of which is unstable above a critical wavenumber for any non-zero flow velocity of the superfluid with respect to the solid.