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arXiv · 2109.14620

Magnetic Hair and Reconnection in Black Hole Magnetospheres

Ashley Bransgrove·Bart Ripperda·Alexander Philippov
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Abstract

The no-hair theorem of general relativity states that isolated black holes are characterized by three parameters: mass, spin, and charge. In this Letter we consider Kerr black holes endowed with highly magnetized plasma-filled magnetospheres. Using general relativistic kinetic plasma and resistive magnetohydrodynamics simulations, we show that a dipole magnetic field on the event horizon opens into a split-monopole and reconnects in a plasmoid-unstable current-sheet. The no-hair theorem is satisfied, in the sense that all components of the stress-energy tensor decay exponentially in time. We measure the decay time of magnetic flux on the event horizon for plasmoid-dominated reconnection in collisionless and collisional plasma. The reconnecting magnetosphere should be a powerful source of hard X-ray emission when the magnetic field is strong.

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Ashley Bransgrove, Bart Ripperda, Alexander Philippov. 2021-09-29. Magnetic Hair and Reconnection in Black Hole Magnetospheres. https://doi.org/10.1103/physrevlett.127.055101

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