Dec 11 – 15, 2023
Tsung-Dao Lee Institute
Asia/Shanghai timezone

Electromagnetic fireworks from erupting magnetars

Dec 13, 2023, 3:07 PM
Hall # 9

Hall # 9

Contributed talk in mini symposium Plasma Astrophysics


Jens Mahlmann (Columbia University)


Highly magnetized neutron stars are a source of extreme transients observed in different bands, like the fast radio burst (FRB) and associated hard X-ray burst from the Galactic magnetar SGR 1935+2154. The origin of such outbursts, hard X-rays on the one hand and millisecond duration FRBs on the other hand, is still unknown. We present a global model for various kinds of such magnetar outbursting activities. Crustal surface motions can twist the inner magnetar magnetosphere by shifting the frozen-in footpoints of magnetic field lines. We discuss criteria for various instabilities of 3D twisted flux bundles in the force-free dipolar magnetospheres and compare their energetic properties to observations of magnetar X-ray flares. We then connect such activities to recently developed FRB generation mechanisms in the outer magnetosphere of a magnetar. In a reconnection-mediated model, a magnetic pulse induced by a magnetar flare collides with the current sheet of the magnetar wind, compresses, and fragments it into a self-similar chain of magnetic islands. Time-dependent plasma currents created during their collisions produce relatively narrow-band GHz emission with luminosities sufficient to explain bright extragalactic FRBs. Alternatively, a so far unexplored shock-mediated FRB mechanism can convert magnetic perturbations of the magnetar wind to radio waves.

Primary author

Jens Mahlmann (Columbia University)


Alexander Philippov (University of Maryland) Anatoly Spitkovsky (Princeton University) Lorenzo Sironi (Columbia University)

Presentation materials