Force-free Currents and the Newman-Penrose Tetrad of a Kerr Black Hole: Exact Local Solutions

Understand

In a previous article we derived a class of solutions to the force-free magnetosphere in a Kerr background.

• Here, the streaming surface, defined by constant values of the toriodal component of the electromagnetic vector potential $A$, were generated by constant values of $\theta$.
• The electromagnetic current vector flowed along the in-falling principle null geodesic vector of the geometry.
• Subsequently, we generalized this to obtain an out-going principle null geodesic vector as well.