中国物理B ›› 2005, Vol. 14 ›› Issue (2): 439-447.doi: 10.1088/1009-1963/14/2/038

• • 上一篇    

Magnetic extraction of energy from black hole accretion disc and its application to astrophysics

叶永春, 汪定雄, 龚小龙   

  1. Department of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
  • 收稿日期:2004-04-21 修回日期:2004-10-31 出版日期:2005-03-02 发布日期:2005-03-02
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos 10173004, 10373006 and 10121503).

Magnetic extraction of energy from black hole accretion disc and its application to astrophysics

Ye Yong-Chun (叶永春), Wang Ding-Xiong (汪定雄), Gong Xiao-Long (龚小龙)   

  1. Department of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
  • Received:2004-04-21 Revised:2004-10-31 Online:2005-03-02 Published:2005-03-02
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos 10173004, 10373006 and 10121503).

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摘要： A new configuration of magnetic field (NCMF) in black hole (BH) magnetosphere is proposed by considering the effects of the screw instability. Three mechanisms of extracting energy magnetically are involved in the NCMF: (1) the Blandford—Znajek (BZ) process; (2) the magnetic coupling (MC) process; (3) a new scenario (henceforth the DL process) for extracting rotational energy from the disc, which is related to the open field lines connecting the disc with the astrophysical load. The expressions for the powers and torques of the above energy mechanisms are derived by using two kinds of the equivalent circuits. It turns out that the power and efficiency of extracting energy magnetically from the BH accretion disc are all augmented in the NCMF. It is shown that a very steep emissivity can be produced in a NCMF, which is consistent with the recent XMM-Newton observation of the nearby bright Seyfert 1 galaxy MCG-6-30-15.

关键词: black holes, black hole physics, accretion discs, emissivity index

Abstract: A new configuration of magnetic field (NCMF) in black hole (BH) magnetosphere is proposed by considering the effects of the screw instability. Three mechanisms of extracting energy magnetically are involved in the NCMF: (1) the Blandford—Znajek (BZ) process; (2) the magnetic coupling (MC) process; (3) a new scenario (henceforth the DL process) for extracting rotational energy from the disc, which is related to the open field lines connecting the disc with the astrophysical load. The expressions for the powers and torques of the above energy mechanisms are derived by using two kinds of the equivalent circuits. It turns out that the power and efficiency of extracting energy magnetically from the BH accretion disc are all augmented in the NCMF. It is shown that a very steep emissivity can be produced in a NCMF, which is consistent with the recent XMM-Newton observation of the nearby bright Seyfert 1 galaxy MCG-6-30-15.

Key words: black holes, black hole physics, accretion discs, emissivity index

中图分类号:  (Black holes)

  • 97.60.Lf
97.10.Ld (Magnetic and electric fields; polarization of starlight) 98.62.En (Electric and magnetic fields) 98.62.Mw (Infall, accretion, and accretion disks) 94.30.-d (Physics of the magnetosphere) 04.70.-s (Physics of black holes)