Repeating Fast Radio Bursts from Magnetars with Low Magnetospheric Twist

Understand

We analyze the statistics of pulse arrival times in fast radio burst (FRB) 121102 and demonstrate that they are remarkably similar to statistics of magnetar high-energy short bursts.

• Motivated by this correspondence, we propose that repeating FRBs are generated during short bursts in the closed field line zone of magnetar magnetospheres via a pulsar-like emission mechanism.
• Crustal slippage events dislocate field line foot points, initiating intense particle acceleration and pair production, giving rise to coherent radio emission similar to that generated near pulsar polar caps.
• We argue that the energetics of FRB 121102 can be readily accounted for if the efficiency of the conversion of Poynting flux into coherent radio emission is $\sim10^{-4}-10^{-2}$, values consistent with empirical efficiencies of radio emission in pulsars and radio-loud magnetars.