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Title: Electromagnetic Fireworks: Fast Radio Bursts from Rapid Reconnection in the Compressed Magnetar Wind
Abstract One scenario for the generation of fast radio bursts (FRBs) is magnetic reconnection in a current sheet of the magnetar wind. Compressed by a strong magnetic pulse induced by a magnetar flare, the current sheet fragments into a self-similar chain of magnetic islands. Time-dependent plasma currents at their interfaces produce coherent radiation during their hierarchical coalescence. We investigate this scenario using 2D radiative relativistic particle-in-cell simulations to compute the efficiency of the coherent emission and to obtain frequency scalings. Consistent with expectations, a fraction of the reconnected magnetic field energy, f ∼ 0.002, is converted to packets of high-frequency fast magnetosonic waves, which can escape from the magnetar wind as radio emission. In agreement with analytical estimates, we find that magnetic pulses of 10 47 erg s −1 can trigger relatively narrowband GHz emission with luminosities of approximately 10 42 erg s −1 , sufficient to explain bright extragalactic FRBs. The mechanism provides a natural explanation for a downward frequency drift of burst signals, as well as the ∼100 ns substructure recently detected in FRB 20200120E .
Authors:
; ; ; ;
Award ID(s):
1814708 1909458
Publication Date:
NSF-PAR ID:
10340757
Journal Name:
The Astrophysical Journal Letters
Volume:
932
Issue:
2
Page Range or eLocation-ID:
L20
ISSN:
2041-8205
Sponsoring Org:
National Science Foundation
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