Effects of magnetohydrodynamic accretion flows on global structure of a Kerr black-hole magnetosphere

Nitta, S.; Takahashi, Masaaki; Tomimatsu, Akira

doi:10.1103/physrevd.44.2295

Cited by 69 publications

(92 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The GS equation was derived in the Newtonian case [36], the Schwarzschild spacetime case [37], and the Kerr spacetime case [38,39]. The flux function Ψ is such that it is constant over each surface generated by rotating the magnetic field lines (or equivalently the flow lines) about the axis of symmetry and the GS equation determines the transfield equilibrium.…”

Section: Introductionmentioning

confidence: 99%

Grad-Shafranov equation in noncircular stationary axisymmetric spacetimes

Ioka

Sasaki

2003

Phys. Rev. D

View full text Add to dashboard Cite

A formulation is developed for general relativistic ideal magnetohydrodynamics in stationary axisymmetric spacetimes. We reduce basic equations to a single second-order partial differential equation, the so-called Grad-Shafranov (GS) equation. Our formulation is most general in the sense that it is applicable even when a stationary axisymmetric spacetime is noncircular, that is, even when it is impossible to foliate a spacetime with two orthogonal families of two-surfaces. The GS equation for noncircular spacetimes is crucial for the study of relativistic stars with a toroidal magnetic field or meridional flow, such as magnetars, since the existence of a toroidal field or meridional flow violates the circularity of a spacetime. We also derive the wind equation in noncircular spacetimes, and discuss various limits of the GS equation.PACS numbers: 04.20.Cv,04.40. Dg,52.30.Cv,95.30.Qd,95.30.Sf,97.10.Cv

show abstract

Section: Introductionmentioning

confidence: 99%

Grad-Shafranov equation in noncircular stationary axisymmetric spacetimes

Ioka

Sasaki

2003

Phys. Rev. D

View full text Add to dashboard Cite

show abstract

“…The basic idea of the black hole-disk connection of magnetic field lines has been sug-gested by some authors (e.g., [16,17,18,19,20,21]). The realistic features of magnetic field lines have been presented by [12,15,22,23,24,25]. In an astrophysical point of view, the magnetic connection between the black hole and the disk would play a very important role.…”

Section: Discussionmentioning

confidence: 99%

Constraints on the evolution of black hole spin due to magnetohydrodynamic accretion

Takahashi

Tomimatsu

2008

Phys. Rev. D

Self Cite

View full text Add to dashboard Cite

Stationary and axisymmetric ideal magnetohydrodynamic (MHD) accretion onto a black hole is studied analytically. The accreting plasma ejected from a plasma source with low velocity must be super-fast magnetosonic before passing through the event horizon. We work out and apply a trans-fast magnetosonic solution without the detailed analysis of the regularity conditions at the magnetosonic point, by introducing the bending angle β of magnetic field line, which is the ratio of the toroidal and poloidal components of the magnetic field. To accrete onto a black hole, the transmagnetosonic solution has some restrictions on β, which are related to the field-aligned parameters of the MHD flows. One of the restrictions gives the boundary condition at the event horizon for the inclination of a magnetic field line. We find that this inclination is related to the energy and angular momentum transport to the black hole. Then, we discuss the spin-up/down process of a rotating black hole by cold MHD inflows in a secular evolution timescale. There are two asymptotic states for the spin evolution. One is that the angular velocity of the black hole approaches to that of the magnetic field line, and the other is that the spin-up effect by the positive angular momentum influx and the spin-down effect by the energy influx (as the mass-energy influx) are canceled. We also show that the MHD inflows prevents the evolution to the maximally rotating black hole.PACS numbers: 97.60. Lf, 95.30.Qd, 95.30.Sf

show abstract

“…When we consider accretion through high-latitude regions above the event horizon near the hole's rotational axis (see Nitta, Takahashi & Tomimatsu 1991;Tomimatsu & Takahashi 2001), we can expect as an X-ray source a hot ringed area around the axis. Our extended future work will include the application of our current work to realistic models of a black hole magnetosphere as the central engine of accretion-powered AGNs.…”

Section: Summary and Concluding Remarksmentioning

confidence: 99%

“…(Note that to determine the magnetic field configuration we should treat the equation of cross-field momentum balance [Grad-Shafranov equation]; the general relativistic extension was obtained by Nitta, Takahashi & Tomimatsu 1991. However, the task is very complicated, so that here we use only a given magnetic field configuration; see x 5.) The flow must pass through the fast magnetosonic point (TNTT90).…”

Section: Basic Equations Of General Relativisticmentioning

confidence: 99%

“…Phinney (1983) first extended his general studies of black hole magnetospheres to accretion-powered AGNs, adopting the magnetohydrodynamics (MHD). In the early 1990s, Takahashi et al (1990, hereafter TNTT90), Nitta, Takahashi, & Tomimatsu (1991), and Hirotani et al (1992) investigated both inflow and outflow of material in black hole magnetospheres. Their approach was a general relativistic unified MHD description of both the matter accretion process and the electromagnetic process in the magnetosphere.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Magnetohydrodynamic Shock Conditions for Accreting Plasma onto Kerr Black Holes. I.

Takahashi

Rilett

Fukumura

et al. 2002

ApJ

Self Cite

View full text Add to dashboard Cite

We extend the work by Appl and Camenzind for special relativistic magnetohydrodynamic (MHD) jets to fully general relativistic studies of standing shock formation for accreting MHD plasma in a rotating, stationary, and axisymmetric black hole magnetosphere. All the postshock physical quantities are expressed in terms of the relativistic compression ratio, which can be obtained in terms of preshock quantities. Then, the downstream state of a shocked plasma is determined by the upstream state of the accreting plasma. In this paper sample solutions are presented for slow magnetosonic shocks for accreting flows in the equatorial plane. We find that some properties of the slow magnetosonic shock for the rotating magnetosphere can behave like a fast magnetosonic shock. In fact, it is confirmed that in the limit of weak gravity for the upstream nonrotating accretion plasma where the magnetic field lines are leading and rotating, our results are very similar to the fast magnetosonic shock solution by Appl and Camenzind. However, we find that the situation becomes far more complicated because of the effects of strong gravity and rotation, such as the frame-dragging effects. We show the tendency that the large spin of the black hole makes the slow magnetosonic shock strong for the accretion solutions with the same energy flux.

show abstract

Effects of magnetohydrodynamic accretion flows on global structure of a Kerr black-hole magnetosphere

Cited by 69 publications

References 8 publications

Grad-Shafranov equation in noncircular stationary axisymmetric spacetimes

Grad-Shafranov equation in noncircular stationary axisymmetric spacetimes

Constraints on the evolution of black hole spin due to magnetohydrodynamic accretion

Magnetohydrodynamic Shock Conditions for Accreting Plasma onto Kerr Black Holes. I.

Contact Info

Product

Resources

About