Sudden discharge of young charged magnetars as a new model for FRBs

Abstract

We propose a new model for Fast Radio Bursts (FRBs) based on a sudden discharge of a charged young magnetar, caused by the short falling timescale of oppositely charged particles onto the magnetar. In this scenario, curvature radiation is emitted by particles accelerated at relativistic by the strong electric fields produced by the disconnection and the subsequent reconnection of the magnetic field lines, a process triggered by the sudden discharge. We modeled the magnetars as charged neutron stars in the static approximation using the exterior metric by the Reissner-Nordström. We also adopted an electrical charge distribution proportional to the mass-energy density, although our results are not strongly sensitive to the specific star’s charge distribution, only to the total charge. Our calculations show that the discharge and emission timescales are several milliseconds, compatible with the FRB phenomena for magnetars with a total charge of ∼1020 C and mass and radius in the range of 1.5 to 3.0 M⊙ and 10 to 45 km, respectively. Furthermore, the calculated total emitted power of a coherent pulse is Ptot ∼ 1042 − 43erg/s, and the frequency range and time scale are also consistent with FRBs astronomical observations. Finally, if the magnetar does not collapse after the discharge, the existence of FRB repeater sources can not rule out the existence of a blast repetition after the time needed to magnetosphere recharges and produce a new discharge.