Magnetohydrodynamic flows in Kerr geometry - Energy extraction from black holes

Journal Article · Thu Nov 01 04:00:00 EST 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/169331· OSTI ID:6231647

Takahashi, Masaaki; Nitta, Shinya; Tatematsu, Yoshinori; Tomimatsu, Akira ^[1]

---

1. Nagoya Univ. (Japan)

This paper studies steady axisymmetric flows of a relativistic ideal magnetohydrodynamical (MHD) fluid in the magnetosphere of a Kerr black hole. It is assumed that an inward flow due to the strong gravity and a centrifugally driven outward flow originate from the plasma's source with zero poloidal velocity. The MHD flows must become super-Alfvenic to fall into the event horizon or reach infinity along the magnetic field lines. The approach is to analyze the poloidal flow equation at the Alfven surface. The solutions are characterized by the angular velocity of the magnetic field lines and the positions of the plasma injection and the Alfven point. It is also found that the MHD inflow can carry a negative energy flux into the event horizon. This result is discussed in relation to the energy extraction from the rotating black hole and the acceleration of winds or jets. 23 refs.

• OSTI ID: 6231647
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 363; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ASTROPHYSICS
ATMOSPHERES
BLACK HOLES
FLUID MECHANICS
GALAXY NUCLEI
GRAVITATION
HYDRODYNAMICS
HYDROMAGNETIC WAVES
KERR METRIC
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MECHANICS
METRICS
MOTION
PLASMA
PLASMA JETS
ROTATION
STELLAR ACTIVITY
STELLAR ATMOSPHERES
STELLAR MAGNETOSPHERES
STELLAR WINDS