ForceFree Magnetic Fields on an Extreme ReissnerNordstrom 无力磁场域上一个极端ReissnerNordstromde.ppt

* ???. ?Magnetic fields without a current sheet. ?Differential rotating magnetic fields ?The Meissner effect in extreme Kerr black holes 17/July/2009 12th MG meeting , Paris * * * 12th MG meeting , Paris 12th MG meeting , Paris 12th MG meeting , Paris 12th MG meeting , Paris 12th MG meeting , Paris 12th MG meeting , Paris 12th MG meeting , Paris Osaka City University Yousuke Takamori Collaborators : Hideki.Ishihara(OCU), Ken-ichi.Nakao(OCU), Masashi.Kimura(OCU),and Chul-Moon Yoo (APCTP) * 17/July/2009 12th MG meeting , Paris ?Introduction ?Force-free magnetic fields around an extreme Reissner-Nordstrom black hole ?Exapmles ① Vacuum ②Non-rotating magnetic fields ③Rotating magnetic fields * 17/July/2009 12th MG meeting , Paris Active Galactic Nuclei(AGN) * Black holes would be central engine. If the Blandford-Znajek mechanism works to extract energy of the black hole, magnetic fields play an important role. 17/July/2009 12th MG meeting , Paris Electromagnetically energy extraction from a Kerr black hole. rotation of the magnetic field line magnetic field line rotation of the black hole ＢＨ The rotational energy of a Kerr black hole can be extracted electromagnetically. The Poynting flux at the event horizon ：radial component of the magnetic flux density 　　 ：angular velocity of the black hole　　 * ：angular velocity of magnetic field lines　　 (Blandford and Znajek, 1977) 17/July/2009 12th MG meeting , Paris The efficiency of energy extraction would decrease by the Meissner effect of the black holes in the vacuum case. Does the Meissner effect appear in the cases that some current exist? * The energy flux depends on magnetic field configurations at the horizon. 　　 Stationary and axisymmetric magnetic fields in a vacuum are expelled from the event horizon of extremely rotating black holes. (Bicak, 1976) 　　 ( at the horizon.) 17/July/2