Abstract： The screw instability of the magnetic field is discussed based on its poloidal configuration generated by a single toroidal electric current flowing in the equatorial plane of a Kerr black hole (BH). The rotation of the BH relative to the disc induces an electromotive force, which in turn results in a poloidal electric current. By using Ampere's law, we calculate the toroidal component of the magnetic field and derive a criterion for the screw instability of the magnetic field connecting the rotating BH with its surrounding disc. It is determined that the screw instability is related to two parameters: the radius of the disc and the BH spin. The occurrence of screw instability is depicted in a parameter space. In addition, we discuss the effect of the screw instability on magnetic extraction of energy from the rotating BH.
(Galactic nuclei (including black holes), circumnuclear matter, and bulges)
引用本文:
AN Xiao-Xia;WANG Ding-Xiong;GAN Zhao-Ming. Connection of Screw Instability with Electric Current in an Accretion Disc around a Black Hole[J]. 中国物理快报, 2005, 22(9): 2455-2458.
AN Xiao-Xia, WANG Ding-Xiong, GAN Zhao-Ming. Connection of Screw Instability with Electric Current in an Accretion Disc around a Black Hole. Chin. Phys. Lett., 2005, 22(9): 2455-2458.
2005, Vol. 22 
