Magnetospheric Signatures of Striped Black Hole Jets

The successive advection of alternating-polarity magnetic loops onto a spinning black hole can launch a jet laced with “stripes” of alternating magnetic field. Magnetic reconnection between such stripes may power in situ jet acceleration and particle acceleration – important for explaining observed phenomena such as relativistic jet bulk motion and rapid gamma-ray flares. On much smaller magnetospheric scales, it is magnetic reconnection in the first place that tears the loops open and loads them into the jet as polarity-reversing stripes. Thus, besides their large-scale observables, striped jets may yield magnetospheric signatures connected to phenomena observed close to black holes (such as gamma-ray flares and astrometric variations). In this study, we probe the physical and observable characteristics of magnetospheric striped-jet launching using novel general relativistic particle-in-cell simulations. These simulations provide a first-principles view into several aspects of the loop advection and ejection problem, including: the electromagnetic power delivered to the nascent jet; the energy consumed to accelerate particles during reconnection-mediated loop ejection; the radiation from such energized particles; and variations of all these aspects with respect to phase in the loop advection and ejection cycle. Thus characterizing the magnetospheric counterpart of a large-scale striped jet provides additional constraints with which the striped jet paradigm may be confronted.