Exact Solutions to Force-Free Electrodynamics in Black Hole Backgrounds

Understand

A shared property of several of the known exact solutions to the equations of force-free electrodynamics is that their charge-current four-vector is \textit{null}.

• We examine the general properties of null-current solutions and then focus on the principal congruences of the Kerr black hole spacetime.
• We obtain a large class of exact solutions, which are in general time-dependent and non-axisymmetric.
• These solutions include waves that, surprisingly, propagate without scattering on the curvature of the black hole's background.