Damghan University
Astronomical Society of Iran
Iranian Journal of Astronomy and Astrophysics
2322-4924
2383-403X
4
3
2017
12
01
Calculation of the relativistic bulk tensor and shear tensor of relativistic accretion flows in the Kerr metric.
205
221
EN
Mahboobe
Moeen
Science department,Faculty member, Kosar University of Bojnord, Iran
dr.moeen@kub.ac.ir
10.22128/ijaa.2017.122
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.
relativistic viscosity,relativistic bulk tensor,relativistic shear tensor,relativistic shear stress viscosity,black holes accretion disks,relativistic flows
http://ijaa.du.ac.ir/article_122.html
http://ijaa.du.ac.ir/article_122_c850f8252ffbb5a2c5bbc939a691b85f.pdf
Damghan University
Astronomical Society of Iran
Iranian Journal of Astronomy and Astrophysics
2322-4924
2383-403X
4
3
2017
12
01
Finite temperature correlation function of two dissipative massive scalar ﬁelds: Thermoﬁeld approach
223
230
EN
Marjan
Jafari
Department of Physics, Faculty of Science, Imam Khomeini International University, P.O.Box 34148-96818,
Qazvin, Iran
10.22128/ijaa.2017.123
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.
massive scalar ﬁeld,correlation function,dissipative,thermoﬁeld dynamics
http://ijaa.du.ac.ir/article_123.html
http://ijaa.du.ac.ir/article_123_f8de2feace3527d44611adc4fc6ff487.pdf
Damghan University
Astronomical Society of Iran
Iranian Journal of Astronomy and Astrophysics
2322-4924
2383-403X
4
3
2017
12
01
Introducing Stable Real Non-Topological Solitary Wave Solutions in 1+1 Dimensions
231
244
EN
Mohammad
mohammadi
0000-0002-8057-237X
Physics Department, Persian Gulf University, Bushehr 75169, Iran.
physmohammadi@pgu.ac.ir
Ali Reza
Olamaei
Jahrom University, Jahrom 74135-111, Iran
olamaei@jahromu.ac.ir
10.22128/ijaa.2017.124
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.
non-linear KG systems,non-topological,solitary wave solutions,stability,soliton
http://ijaa.du.ac.ir/article_124.html
http://ijaa.du.ac.ir/article_124_7471a0364c7fc6b178e36236c967ef18.pdf
Damghan University
Astronomical Society of Iran
Iranian Journal of Astronomy and Astrophysics
2322-4924
2383-403X
4
3
2017
12
01
Multi fluidity and Solitary wave stability in cold quark matter: core of dense astrophysical objects
245
260
EN
Azam
Ghaani
Department of Physics, Ferdowsi University of Mashhad, 91775-1436 Mashhad, Iran
az.ghaani@stu-mail.um.ac.ir
Parvin
Eslami
Department of Physics, Ferdowsi University of Mashhad, 91775-1436 Mashhad, Iran
eslami@ferdowsi.um.ac.ir
Mohsen
Sarbishaei
Department of Physics, Ferdowsi University of Mashhad, 91775-1436 Mashhad, Iran
sarbishei@um.ac.ir
Kurosh
Javidan
0000-0002-7596-4280
Department of Physics, Ferdowsi University of Mashhad, 91775-1436 Mashhad, Iran
javidan@um.ac.ir
10.22128/ijaa.2017.125
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).
keyword
http://ijaa.du.ac.ir/article_125.html
http://ijaa.du.ac.ir/article_125_04ef1add2900a30c735cb4975b69c650.pdf
Damghan University
Astronomical Society of Iran
Iranian Journal of Astronomy and Astrophysics
2322-4924
2383-403X
4
3
2017
12
01
Oscillations of a Giant Solar Tornado
261
271
EN
Fatemeh
Hashemi-Nasab
Department of Physics, University of Zanjan, P.O. Box 45195-313, Zanjan, Iran
fatima.hashemi@gmail.com
Neda
Dadashi
0000-0001-7881-1688
Physics Department, Faculty of Science, University of Zanjan, Zanjan, Iran
dadashi@znu.ac.ir
Nasibeh
Alipour-Rad
Department of Physics, University of Zanjan, P.O. Box 45195-313, Zanjan, Iran
alipourrad@znu.ac.ir
YousefAli
Abedini
Department of Physics, University of Zanjan, P.O. Box 45195-313, Zanjan, Iran
10.22128/ijaa.2017.126
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 1.95×10<sup>18</sup> erg to 3.36×10<sup>19</sup> 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.
Sun: Corona,Sun: Tornado,Sun: UV radiation,Sun: Oscillations
http://ijaa.du.ac.ir/article_126.html
http://ijaa.du.ac.ir/article_126_eaa05200a6d65c33dd1a39e503451a34.pdf
Damghan University
Astronomical Society of Iran
Iranian Journal of Astronomy and Astrophysics
2322-4924
2383-403X
4
3
2017
12
01
Thermal measurement induced disturbance in the Bose-Hubbard Hamiltonian
273
282
EN
Hamed
Jafarzadeh
Quchan University of Technology, Quchan, Iran
Hakimeh
Jaghouri
Department of Physics, Ferdowsi University of Mashhad, 91775-1436, Mashhad, Iran
10.22128/ijaa.2017.129
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.
qutrit,measurement induced disturbance,Bose-Hubbard Hamiltonian
http://ijaa.du.ac.ir/article_129.html
http://ijaa.du.ac.ir/article_129_589fb68d43c6d60852ad90eb7755f445.pdf