Bransgrove Ashley, Ripperda Bart, Philippov Alexander
Physics Department and Columbia Astrophysics Laboratory, Columbia University, 538 West 120th Street, New York, New York 10027, USA.
Center for Computational Astrophysics, Flatiron Institute, 162 Fifth Avenue, New York, New York 10010, USA.
Phys Rev Lett. 2021 Jul 30;127(5):055101. doi: 10.1103/PhysRevLett.127.055101.
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.
广义相对论的无毛定理表明，孤立黑洞由三个参数表征：质量、自旋和电荷。在本信函中，我们考虑具有高度磁化的充满等离子体的磁层的克尔黑洞。通过广义相对论动力学等离子体和电阻磁流体动力学模拟，我们表明事件视界上的偶极磁场会打开形成分裂单极，并在一个等离子体团不稳定的电流片中重新连接。从应力 - 能量张量的所有分量随时间呈指数衰减的意义上来说，无毛定理是成立的。我们测量了无碰撞和有碰撞等离子体中以等离子体团主导的重新连接情况下事件视界上磁通量的衰减时间。当磁场很强时，重新连接的磁层应该是硬X射线发射的强大来源。
