Determine whether charging shuts off in the extreme black-hole limit

Determine whether the charge-selective accretion mechanism shuts off in the extreme-spin limit of a rotating black hole immersed in an aligned magnetic field, particularly when plasma currents suppress magnetic-flux expulsion from the horizon.

Background

In the vacuum Wald solution, magnetic flux is expelled from the horizon as the spin approaches extremality, suggesting that the charging mechanism could cease. Conductive-plasma simulations, however, indicate that magnetospheric currents substantially suppress this Meissner-like expulsion.

The competing effects make the behavior of charge accumulation in the extreme-spin limit nontrivial. The paper’s simulations approach high spin but do not directly establish the limiting behavior of the kinetic charging process at exact extremality.