  In classical inviscid fluids, parallel vortices perturbed by Kelvin waves may
exhibit the Crow instability, where the mutual interaction of the Kelvin modes
renders them dynamically unstable. This results in the mutual approach and
reconnection of the vortices, leading to a cascaded decay into smaller and
smaller vortex loops. We study the Crow instability of quantum vortex lines in
a superfluid enjoying the anisotropic, long-ranged dipole-dipole interaction
through mean-field simulations of the dynamics of the superfluid order
parameter. We observe that both the strength and direction of the dipole-dipole
interaction play a crucial role in determining the Kelvin modes that are
dynamically favoured. This is shown to be linked to effective enhancements or
suppressions of the vortices' curvature and can be explained by the effective
dipole-dipole interaction between the vortex lines themselves. This paves the
way to a deeper understanding of vortex reconnection dynamics, vortex loop
cascading and turbulence in dipolar superfluids.
