Can one increase the luminosity of a Schwarzschild black hole?
  We illustrate how Hawking's radiance from a Schwarzschild black hole is modified by the electrostatic self-interaction of the emitted charged particles. A W.K.B approximation shows that the probability for a self-interacting charged particle to propagate from the interior to the exterior of the horizon is increased relative to the corresponding probability for neutral particles. We also demonstrate how the electric potential of a charged test object in the black hole's vicinity gives rise to pair creation. We analyze this phenomenon semiclassically by considering the existence of the appropriate Klein region. Finally we discuss the possible energy source for the process. 
Avraham E. Mayo