Black holes under external influence

JIRI BICAK

Institute of Theoretical Physics, Faculty of Mathematics and Physics, Charles University, V Holesovickachch 2, 180 00 Prague 8, Czech Republic

Abstract.

The work on black holes immersed in external fields is reviewed in both test-field approximation and within exact solutions. In particular we pay attention to the effect of the expulsion of the flux of external fields across charged and rotating black holes which are approaching extremal states. Recently this effect has been shown to occur for black hole solutions in string theory. We also discuss black holes surrounded by rings and disks and rotating black holes accelerated by strings.

Keywords: Black holes; magnetic fields and disks around; flux expulsion from; acceleration of.

Pacs No. 04.70.-s; 97.60.Lf; 04.40.Nr.