Phase portraits for the motion of charged particles around a weakly magnetized rotating black hole

Abstract

We study the phase portraits of a charged particle orbiting around a weakly magnetized Kerr black hole. For prograde orbits in anti-Larmor motion, the center-saddle coalescence point approaches the event horizon as the spin a < 1/2 increases. For spin 1/2 ≤ a < 1, the coalescence point moves away from the horizon. Bound orbits are observed in the phase portraits having center and saddle fixed points which exist for b less than the coalescence point {r_c, b_c}.