Analytical studies have raised the concern that a mysterious expulsion of
magnetic field lines by a rapidly-spinning black hole (dubbed the black hole
Meissner effect) would shut down the Blandford-Znajek process and quench the
jets of active galactic nuclei and microquasars. This effect is however not
seen observationally or in numerical simulations. Previous attempts at
reconciling the predictions with observations have proposed several mechanisms
to evade the Meissner effect. In this paper, we identify a new evasion
mechanism and discuss its observational significance. Specifically, we show
that the breakdown of stationarity is sufficient to remove the expulsion of the
magnetic field at all multipole orders, and that the associated temporal
variation is likely turbulent due to the existence of efficient mechanisms for
sharing energy across different modes. Such an intrinsic (as opposed to being
driven externally by, e.g., changes in the accretion rate) variability of the
electromagnetic field can produce the recorded linear correlation between
microvariability amplitudes and mean fluxes, help create magnetic randomness
and seed sheared magnetic loops in jets, and lead to a better theoretical fit
to the X-ray microvariability power spectral density.Comment: 16 pages, 9 figure
