The shell of incoherent charged matter falling onto a charged rotating black hole

The motion of the shell of charged test particles falling radially from rest at infinity with zero total angular momentum onto a Kerr-Newman black hole is studied. The shell, initially spherical, becomes prolate along the axis of symmetry of the hole during the fall. The shape of the shell from the viewpoint of distant observers is characterized by means of the photons moving along geodesics of the outgoing principal null congruence. The motion of the shell is examined analytically for large distances and near the horizon. In the special case, when at large distances of the hole the attractive Newton gravitational force is compensated by the repulsive Coulomb force, the complete motion is given explicitly in terms of elementary functions.