Plasma Drift Velocities in the Curved Spacetimes of Black Holes

The gyroradii of charges in the plasmas around black holes are more than ten orders of magnitude smaller than the macroscopic length scales of the systems. Modeling the drift of these charges across magnetic field lines has presented significant challenges arising from the absence of a covariant guiding-center formalism in curved spacetimes. I will discuss how utilizing a novel covariant drift-kinetic formalism for charge trajectories in flat spacetimes has enable the determination of the three primary drift velocities caused by gradients in the magnetic field as well as the presence of electric and gravitational fields. Our findings indicate that, while the electric-field drift velocity remains unaffected by the spacetime curvature, the gradient and gravitational drift velocities are substantially modified, with their magnitudes increasing rapidly near the black-hole horizons.

Research funded by Georgia Institute of Technology.