Effective potential of particles in the oblique black hole magnetosphere
  Dynamics of charged matter in the oblique black hole magnetosphere is investigated. In particular, we adopt a model consisting of a rotating black hole embedded in the external large-scale magnetic field that is inclined arbitrarily with respect to the rotation axis. Breaking the axial symmetry appears to have profound consequences regarding the dynamics of particles and it also poses some methodological difficulties. In this contribution we discuss the applicability of the method of effective potential for the non-axisymmetric model and show that it may only be applied in the appropriate reference frame. 
Ond\v{r}ej Kop\'a\v{c}ek and Vladim\'ir Karas
gr-qc astro-ph.HE