Rotating charged black holes accelerated by an electric field

The Ernst method of removing nodal singularities from the charged C-metric representing uniformly accelerated black holes with mass $m$, charge $q$ and acceleration $A$ by “adding” an electric field $E$ is generalized. Utilizing the new form of the C-metric found recently, Ernst’s simple “equilibrium” condition $mA=qE$ valid for small accelerations is generalized for arbitrary $A$. The nodal singularity is removed also in the case of accelerating and rotating charged black holes, and the corresponding equilibrium condition is determined.