Repeating fast radio bursts with high burst rates by plate collisions in neutron star crusts

Some repeating fast radio burst (FRB) sources show high burst rates, and the physical origin is still unknown. Outstandingly, the first repeater FRB 121102 appears extremely high burst rate with the maximum value reaching 122 h(-1) or even higher. In this work, we propose that the high burst rate of an FRB repeater may be due to plate collisions in the crust of young neutron stars (NSs). In the crust of an NS, vortex lines are pinned to the lattice nuclei. When the relative angular velocity between the superfluid neutrons and the NS lattices is non-zero, a pinned force will act on the vortex lines, which will cause the lattice displacement and the strain on the NS crust growing. With the spin evolution, the crustal strain reaches a critical value, then the crust may crack into plates, and each of plates will collide with its adjacent ones. The Aflven wave could be launched by the plate collisions and further produce FRBs. In this scenario, the predicted burst rate can reach similar to 770 h(-1) for an NS with the magnetic field of 10(13) G and the spin period of 0.01 s. We further apply this model to FRB 121102, and predict the waiting time and energy distribution to be P(t(w)) proportional to t(w)(proportional to tw) with proportional to(tw) similar or equal to - 1.75 and N(E)dE proportional to E(proportional to E)dE with proportional to(E) similar or equal to -1.67, respectively. These properties are consistent with the observations of FRB 121102.

Automated summary

This study proposes that the high burst rate of FRB repeaters may be due to plate collisions in the crust of young neutron stars (NSs). These plate collisions could launch Alven waves and further produce FRBs.