CHARGED-PARTICLE TRAJECTORIES IN A TOROIDAL MAGNETIC AND ROTATION-INDUCED ELECTRIC-FIELD AROUND A BLACK-HOLE

Trajectories of charged particles in a combined poloidal, toroidal mag netic field and a rotation-induced unipolar electric field superposed on a Schwarzschild background geometry have been investigated extensiv ely in the context of accreting black holes. The main purpose of this paper is to obtain a reasonably good insight on the effect of spacetim e curvature on the electromagnetic field surrounding black holes. The coupled equations of motion have been solved numerically and the resul ts have been compared with that for flat spacetime. It is found that t he toroidal magnetic field dominates the induced electric field in det ermining the motion of charged particles in curved spacetime. The comb ined electromagnetic field repels a charged particle from the vicinity of a compact massive object and deconfines the particle from its orbi t. In the absence of a toroidal magnetic field the particle is trapped in a closed orbit. The major role of gravitation is to reduce the rad ius of gyration significantly while the electric field provides an add itional force perpendicular to the circular orbit. Although the effect of inertial frame dragging and the effect of magnetospheric plasma ha ve been neglected, the results provide a reasonably good qualitative p icture of the important role played by gravitation in modifying the el ectromagnetic field near accreting black holes and hence the results h ave potentially important implications on the dynamics of the fluid an d the radiation spectrum associated with accreting black holes.