Calculation of the relativistic bulk tensor and shear tensor of relativistic accretion flows in the Kerr metric.
Mahboobe
Moeen
Science department,Faculty member, Kosar University of Bojnord, Iran
author
text
article
2017
eng
In this paper, we calculate the relativistic bulk tensor and shear tensor of the relativistic accretion ows in the Kerr metric, overall and without any approximation. We obtain the relations of all components of the relativistic bulk and shear tensor in terms of components of four-velocity and its derivatives, Christoffel symbols and metric components in the BLF. Then, these components are derived in the equa-torial plane. To see the behavior of the relativistic bulk tensor and shear tensor in the relativistic accretion disks around the rotating black holes, we introduce a radial form for the radial component of the four-velocity in the LNRF; therefore, all components of the bulk and shear tensor are derived in the BLF. Figures of non-zero components of the bulk tensor and shear tensor are shown for some states. We use the radial model to study the importance and in uence of the relativistic bulk tensor in the accretion disks around the rotating black holes. Also, we see that in some cases bulk tensor may be important and comparable with the shear tensor. Especially, we see that bulk tensor in the inner radii is more important.
Iranian Journal of Astronomy and Astrophysics
Damghan University
Astronomical Society of Iran
2322-4924
4
v.
3
no.
2017
205
221
http://ijaa.du.ac.ir/article_122_c850f8252ffbb5a2c5bbc939a691b85f.pdf
dx.doi.org/10.22128/ijaa.2017.122
Finite temperature correlation function of two dissipative massive scalar ﬁelds: Thermoﬁeld approach
Marjan
Jafari
Department of Physics, Faculty of Science, Imam Khomeini International University, P.O.Box 34148-96818,
Qazvin, Iran
author
text
article
2017
eng
The present paper aims at investigating the manner of two dissipative massive scalar ﬁelds. Two massive scalar ﬁelds that interact with a reservoir were considered and a reservoir was modeled by continuum Klein-Gordon ﬁelds. The Lagrangian of the total system was canonically quantized and the dynamics of the system was determined using the Euler-Lagrange equation. Then, the explicit form of the quantum massive scalar ﬁelds in long-time limit were observed. The propagator of the system and correlation functions were calculated at ﬁnite temperature in the thermoﬁeld dynamics formalizem.
Iranian Journal of Astronomy and Astrophysics
Damghan University
Astronomical Society of Iran
2322-4924
4
v.
3
no.
2017
223
230
http://ijaa.du.ac.ir/article_123_f8de2feace3527d44611adc4fc6ff487.pdf
dx.doi.org/10.22128/ijaa.2017.123
Introducing Stable Real Non-Topological Solitary Wave Solutions in 1+1 Dimensions
Mohammad
mohammadi
Physics Department, Persian Gulf University, Bushehr 75169, Iran.
author
Ali Reza
Olamaei
Jahrom University, Jahrom 74135-111, Iran
author
text
article
2017
eng
By adding a proper term to the Lagrangian density of a real non-linear KG system with a proposed non-topological unstable solitary wave solution, its stability guaranteed appreciably. This additional term in the new modiﬁed Lagrangian density behaves like a strong internal force which stands against any arbitrary small deformation in the proposed non-topological solitary wave solution.
Iranian Journal of Astronomy and Astrophysics
Damghan University
Astronomical Society of Iran
2322-4924
4
v.
3
no.
2017
231
244
http://ijaa.du.ac.ir/article_124_7471a0364c7fc6b178e36236c967ef18.pdf
dx.doi.org/10.22128/ijaa.2017.124
Multi fluidity and Solitary wave stability in cold quark matter: core of dense astrophysical objects
Azam
Ghaani
Department of Physics, Ferdowsi University of Mashhad, 91775-1436 Mashhad, Iran
author
Parvin
Eslami
Department of Physics, Ferdowsi University of Mashhad, 91775-1436 Mashhad, Iran
author
Mohsen
Sarbishaei
Department of Physics, Ferdowsi University of Mashhad, 91775-1436 Mashhad, Iran
author
Kurosh
Javidan
Department of Physics, Ferdowsi University of Mashhad, 91775-1436 Mashhad, Iran
author
text
article
2017
eng
Considering the magneto-hydrodynamic equations in a non-relativistic multi uid framework, we study the behavior of small amplitude perturbations in cold quark matter. Magneto-hydrodynamic equations, along with a suitable equation of state for the cold quark matter, are expanded using the reductive perturbation method. It is shown that in small amplitude approximation, such a medium should be considered as a multi- uid system. The result is a nonlinear wave equation which complies with a modied form of the derivative nonlinear Schrodinger equation instead of the KdV equation. Considering the magnetic eld which is supported by the Maxwell's equations, we show that the complete set of equations, create stable solitary waves. An interesting result is the existence of an electric eld component along the direction of magnetic eld which causes a small charge separability in the medium. Properties of this solitonic solution are studied by considering different values for the environmental characters such as background mass density and strength of the magnetic eld (at the scale of compact stars).
Iranian Journal of Astronomy and Astrophysics
Damghan University
Astronomical Society of Iran
2322-4924
4
v.
3
no.
2017
245
260
http://ijaa.du.ac.ir/article_125_04ef1add2900a30c735cb4975b69c650.pdf
dx.doi.org/10.22128/ijaa.2017.125
Oscillations of a Giant Solar Tornado
Fatemeh
Hashemi-Nasab
Department of Physics, University of Zanjan, P.O. Box 45195-313, Zanjan, Iran
author
Neda
Dadashi
Physics Department, Faculty of Science, University of Zanjan, Zanjan, Iran
author
Nasibeh
Alipour-Rad
Department of Physics, University of Zanjan, P.O. Box 45195-313, Zanjan, Iran
author
YousefAli
Abedini
Department of Physics, University of Zanjan, P.O. Box 45195-313, Zanjan, Iran
author
text
article
2017
eng
Solar magnetic tornadoes are known to be one of the mass and energy transport mechanisms from the lower solar atmosphere into the upper layers of the solar corona. A bright spiral structure with two arms is observed using high-cadence EUV images of 171, 193 and 304 Ǻ channels of Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO) on 10th of July 2011 for three hours. The structure studied here looks bright in front of dark background emissions. The rotational energy budget of this tornado is estimated using three different approaches. Results showed the rotational energy ranges between 1.95×1018 erg to 3.36×1019 erg. After correcting for the solar differential rotation, the oscillatory behaviour of the structure is studied using FFT technique. Results show four different regimes of oscillations: 3-min, 5-6 min, 8-11 min, and 15-17 min. The showed origin of each of these oscillations are discussed.
Iranian Journal of Astronomy and Astrophysics
Damghan University
Astronomical Society of Iran
2322-4924
4
v.
3
no.
2017
261
271
http://ijaa.du.ac.ir/article_126_eaa05200a6d65c33dd1a39e503451a34.pdf
dx.doi.org/10.22128/ijaa.2017.126
Thermal measurement induced disturbance in the Bose-Hubbard Hamiltonian
Hamed
Jafarzadeh
Quchan University of Technology, Quchan, Iran
author
Hakimeh
Jaghouri
Department of Physics, Ferdowsi University of Mashhad, 91775-1436, Mashhad, Iran
author
text
article
2017
eng
We study measurement induced disturbance (MID) in a qutrit –qutrit system with considering the effect of the external magnetic field, nonlinear and linear coupling constants and temperature. We show that all of these parameters have effective roles in MID. We also investigate the effect of finite external magnetic fields direction as parallel and anti-parallel on MID, and find some interesting results.
Iranian Journal of Astronomy and Astrophysics
Damghan University
Astronomical Society of Iran
2322-4924
4
v.
3
no.
2017
273
282
http://ijaa.du.ac.ir/article_129_589fb68d43c6d60852ad90eb7755f445.pdf
dx.doi.org/10.22128/ijaa.2017.129