Polar trajectories around a black hole in a magnetic field

1989 ◽  
Vol 67 (10) ◽  
pp. 971-973
Author(s):  
K. D. Krori ◽  
J. C. Sarmah
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Angular Momentum ◽  
Test Particle ◽  
Field Parameter ◽  
Schwarzschild Black Hole ◽  
Magnetic Field Parameter ◽  
Neutral Test ◽  
Test Particles ◽  
The Magnetic Field

In this paper, we present a study of the stable polar trajectories ([Formula: see text] = constant plane) of neutral test particles around a Schwarzschild black hole embedded in a magnetic field. We also show how the nature of these trajectories changes with the variation in the angular momentum of the test particle and the magnetic field parameter.

A magnetized object in Kaluza–Klein theory

1990 ◽  
Vol 68 (7-8) ◽  
pp. 649-654 ◽  
Author(s):  
K. D. Krori ◽  
J. C. Sarmah
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
Gaussian Curvature ◽  
Field Parameter ◽  
Magnetic Field Parameter ◽  
Test Particles ◽  
Klein Theory ◽  
Charged Test ◽  
The Magnetic Field ◽  
Kaluza Klein

In this paper, we present a study of the stable equatorial (θ = π/2) and polar [Formula: see text] trajectories of neutral or charged test particles around a magnetized object in five-dimensional Kaluza–Klein theory. We also show how the nature of these trajectories changes with the variation of the angular momentum of the test particles and with the magnetic-field parameter. We point out that the Gaussian curvature tends to infinity at the Matos surface (defined in the text). A comparison is also made between four-dimensional and five-dimensional studies for equatorial and polar trajectories.

Why only a small fraction of quasars are radio loud?

2018 ◽  
Vol 14 (S342) ◽  
pp. 201-204
Author(s):  
Xinwu Cao
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Angular Momentum ◽  
Angular Velocity ◽  
Strong Magnetic Field ◽  
Weak Magnetic Field ◽  
Thin Disk ◽  
Relativistic Jets ◽  
Jet Formation ◽  
The Magnetic Field

AbstractIt is still a mystery why only a small fraction of quasars contain relativistic jets. A strong magnetic field is a necessary ingredient for jet formation. Gas falls from the Bondi radius RB nearly freely to the circularization radius Rc, and a thin accretion disk is formed within Rc We suggest that the external weak magnetic field threading interstellar medium is substantially enhanced in this region, and the magnetic field at Rc can be sufficiently strong to drive outflows from the disk if the angular velocity of the gas is low at RB. In this case, the magnetic field is efficiently dragged in the disk, because most angular momentum of the disk is removed by the outflows that lead to a significantly high radial velocity. The strong magnetic field formed in this way may accelerate jets in the region near the black hole, either by the Blandford-Payne or/and Blandford-Znajek mechanisms. If the angular velocity of the circumnuclear gas is low, the field advection in the thin disk is inefficient, and it will appear as a radio-quiet (RQ) quasar.

scholarly journals ENERGY ASSOCIATED WITH SCHWARZSCHILD BLACK HOLE IN A MAGNETIC UNIVERSE

2000 ◽  
Vol 15 (19) ◽  
pp. 2979-2986 ◽  
Author(s):  
S. S. XULU
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Uniform Magnetic Field ◽  
Relativistic Effect ◽  
Rest Mass ◽  
Mass Energy ◽  
Schwarzschild Black Hole ◽  
General Relativistic ◽  
The Magnetic Field ◽  
General Relativistic Effect

In this paper we obtain the energy distribution associated with the Ernst space–time (geometry describing Schwarzschild black hole in Melvin's magnetic universe) in Einstein's prescription. The first term is the rest-mass energy of the Schwarzschild black hole, the second term is the classical value for the energy of the uniform magnetic field and the remaining terms in the expression are due to the general relativistic effect. The presence of the magnetic field is found to increase the energy of the system.

scholarly journals Hydromagnetic Flow Past an Exponentially Accelerated Isothermal Vertical Plate with Uniform Mass Diffusion in the Presence of Chemical Reaction of first Order

2013 ◽  
Vol 18 (1) ◽  
pp. 259-267 ◽  
Author(s):  
R. Muthucumaraswamy ◽  
V. Valliammal
Keyword(s):  
Magnetic Field ◽  
Chemical Reaction ◽  
Vertical Plate ◽  
Mass Diffusion ◽  
Field Parameter ◽  
Grashof Number ◽  
Magnetic Field Parameter ◽  
Flow Past ◽  
Laplace Transform Technique ◽  
The Magnetic Field

An exact solution of an unsteady flow past an exponentially accelerated infinite isothermal vertical plate with uniform mass diffusion in the presence of a transverse magnetic field has been studied. The plate temperature is raised to Tw and the species concentration level near the plate is also made to rise Cʹw . The dimensionless governing equations are solved using the Laplace-transform technique. The velocity, temperature and concentration profiles are studied for different physical parameters such as the magnetic field parameter, chemical reaction parameter, thermal Grashof number, mass Grashof number, Schmidt number, time and a. It is observed that the velocity decreases with increasing the magnetic field parameter.

scholarly journals MHD and rotation effects on flow past an accelerated vertical plate with variable temperature and mass diffusion in the presence of chemical reaction

2013 ◽  
Vol 18 (4) ◽  
pp. 1087-1097
Author(s):  
R. Muthucumaraswamy ◽  
N. Dhanasekar ◽  
G. Easwara Prasad
Keyword(s):  
Magnetic Field ◽  
Chemical Reaction ◽  
Vertical Plate ◽  
Variable Temperature ◽  
Field Parameter ◽  
Physical Parameters ◽  
Grashof Number ◽  
Magnetic Field Parameter ◽  
Laplace Transform Technique ◽  
The Magnetic Field

Abstract An exact analysis of rotation effects on an unsteady flow of an incompressible and electrically conducting fluid past a uniformly accelerated infinite isothermal vertical plate, under the action of a transversely applied magnetic field is presented. The plate temperature is raised linearly with time and the concentration level near the plate is also raised to C’w. The dimensionless governing equations are solved using the Laplace-transform technique. The velocity profiles, temperature and concentration are studied for different physical parameters such as the magnetic field parameter, chemical reaction parameter, thermal Grashof number, mass Grashof number, Schmidt number, Prandtl number and time. It is observed that the velocity increases with increasing values of the thermal Grashof number or mass Grashof number. It is also observed that the velocity increases with decreasing values of the magnetic field parameter or rotation parameter Ω.

scholarly journals Chemical Reaction Effects on MHD Flow Past an Impulsively Started Isothermal Vertical Plate with Uniform Mass Diffusion

2014 ◽  
Vol 19 (2) ◽  
pp. 419-426
Author(s):  
P. Chandrakala ◽  
P. Narayana Bhaskar
Keyword(s):  
Magnetic Field ◽  
Chemical Reaction ◽  
Vertical Plate ◽  
Mass Diffusion ◽  
Field Parameter ◽  
Reaction Parameter ◽  
Grashof Number ◽  
Magnetic Field Parameter ◽  
Chemical Reaction Parameter ◽  
The Magnetic Field

Abstract A numerical technique is employed to derive a solution to the transient natural convection flow of an incompressible viscous fluid past an impulsively started infinite isothermal vertical plate with uniform mass diffusion in the presence of a magnetic field and homogeneous chemical reaction of first order. The governing equations are solved using implicit finite-difference method. The effects of velocity, temperature and concentration for different parameters such as the magnetic field parameter, chemical reaction parameter, Prandtl number, Schmidt number, thermal Grashof number and mass Grashof number are studied. It is observed that the fluid velocity decreases with increasing the chemical reaction parameter and the magnetic field parameter.

scholarly journals Skin Friction and Heat Transfer in Combined Convection from a Sphere to a Non-Newtonian Fluid

2017 ◽  
Vol 65 (1) ◽  
pp. 21-25
Author(s):  
Nepal C Roy ◽  
Amir Husen
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Nusselt Number ◽  
Skin Friction ◽  
Newtonian Fluid ◽  
Heat Generation ◽  
Field Parameter ◽  
Magnetic Field Parameter ◽  
Combined Convection ◽  
The Magnetic Field

Steady-state laminar combined convection flow of an electrically conducting, non-Newtonian fluid past a sphere is studied numerically. The effects of the power-law index, the mixed convection parameter, the magnetic field parameter and the heat generation or absorption parameter on the skin friction and the heat transfer are illustrated. The skin friction for dilatant fluids is smaller than that for pseudoplastics. Near the stagnation point, the Nusselt number reduces rapidly for pseudoplastics and reaches sharply a maximum value for dilatant fluids. Both the skin friction and the Nusselt number decrease owing to an increase of the magnetic field parameter. Moreover the heat generation produces higher skin friction and lower Nusselt number. Dhaka Univ. J. Sci. 65(1): 21-25, 2017 (January)

scholarly journals Non-linear evolutions of magnetized thick discs around black holes: dependence on the initial data

2020 ◽  
Vol 492 (4) ◽  
pp. 5730-5742
Author(s):  
Alejandro Cruz-Osorio ◽  
Sergio Gimeno-Soler ◽  
José A Font
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Angular Momentum ◽  
Initial Data ◽  
Kerr Black Hole ◽  
Equilibrium Solutions ◽  
Self Consistent ◽  
General Relativistic ◽  
Orbital Periods ◽  
The Magnetic Field

ABSTRACT We build equilibrium solutions of magnetized thick discs around a highly spinning Kerr black hole and evolve these initial data up to a final time of about 100 orbital periods. The numerical simulations reported in this paper solve the general relativistic magnetohydrodynamic equations using the bhac code and are performed in axisymmetry. Our study assumes non-self-gravitating, polytropic, constant angular momentum discs endowed with a purely toroidal magnetic field. In order to build the initial data, we consider three approaches, two of which incorporate the magnetic field in a self-consistent way and a third approach in which the magnetic field is included as a perturbation on to an otherwise purely hydrodynamical solution. To test the dependence of the evolution on the initial data, we explore four representative values of the magnetization parameter spanning from almost hydrodynamical discs to very strongly magnetized tori. The initial data are perturbed to allow for mass and angular momentum accretion on to the black hole. Notable differences are found in the long-term evolutions of the initial data. In particular, our study reveals that highly magnetized discs are unstable, and hence prone to be fully accreted and expelled, unless the magnetic field is incorporated into the initial data in a self-consistent way.

Sign in / Sign up

Export Citation Format

Share Document