scholarly journals Magnetic Field Decay in the Non-superfluid Regions of Neutron Star Cores

1994 ◽  
Vol 147 ◽  
pp. 591-595
Author(s):  
A.G. Muslimov ◽  
H.M. Van Horn
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Simple Model ◽  
Homogeneous Magnetic Field ◽  
Rapid Decline ◽  
Cooling History ◽  
Poloidal Magnetic Field ◽  
Field Decay ◽  
The Magnetic Field ◽  
Urca Process

AbstractWe consider a simple model for the evolution of a poloidal magnetic field initally trapped in a region containing normal npe matter within the outerliquid core of a neutron star. We have performed numerical computations for neutron stars with masses of 1.4, 1.6, and 1.7 M⊙ that undergo very rapid cooling due to the direct Urca process. Because the timescale for the magnetic field decay is directly proportional to T2, such a cooling history produces a rapid decline in the magnetic-field strength B, even for B as low as ∼ 1012 G. In particular, we show that an initially quasi-homogeneous magnetic field of strength B = 1012 G declines during the first ∼ 1 Myr.

scholarly journals The Evolution of the Magnetic Fields of Neutron Stars

1992 ◽  
Vol 128 ◽  
pp. 26-34
Author(s):  
Dipankar Bhattacharya
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Theoretical Models ◽  
Radio Pulsars ◽  
Secular Evolution ◽  
History Of ◽  
Field Decay ◽  
The Magnetic Field

AbstractThe evolution of the magnetic field strength plays a major role in the life history of a neutron star. In this article the observational evidence of field evolution, in particular that of field decay and magnetic alignment, are critically examined. It is concluded that the observed decay of the spindown torque on radio pulsars cannot be caused by a secular evolution of the “obliqueness” of the neutron star, as suggested by some authors. Recent observations provide a strong indication that the decay of the magnetic field strength of a neutron star may be closely related to its evolution in a binary system. Theoretical models for such an evolution are discussed.

scholarly journals Pulsar Spin-Down by 3P2 Superfluid Neutrons

2003 ◽  
Vol 214 ◽  
pp. 175-176
Author(s):  
Xin-Lian Luo ◽  
Qiu-He Peng ◽  
Ming Zhang ◽  
Chih-Kang Chou
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Electromagnetic Radiation ◽  
Magnetic Dipole ◽  
Exponential Model ◽  
Radiation Model ◽  
Dipole Radiation ◽  
Field Decay ◽  
The Magnetic Field ◽  
Pulsar Evolution

To describe pulsar spin-down, a simple combined torque model, that takes into account both the standard magnetic dipole radiation and the electromagnetic radiation from the 3P2 superfluid vortex neutrons inside neutron star, is presented. Using an ordinary exponential model for the magnetic field decay, we investigate pulsar evolution tracks on the diagram, which is quite different from that of the standard magnetic dipole radiation model, especially when the superfluid torque or field decay become dominate.

scholarly journals Non-Stationary Accretion in Her X–1–like Systems

1996 ◽  
Vol 160 ◽  
pp. 537-538
Author(s):  
U. Geppert ◽  
V. Urpin
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Total Mass ◽  
Binary Systems ◽  
High Mass ◽  
Neutron Star Crust ◽  
Solid Region ◽  
Low Mass ◽  
Field Decay ◽  
The Magnetic Field

Accretion heats the neutron star crust thereby decreasing the electric conductivity in the solid region. This leads to a rapid field decay when the currents supporting the field are concentrated in the solid crust (Geppert & Urpin 1994, Urpin & Geppert 1995). Depending on the duration of the accretion phase and on the total mass accreted the field can be decreased by 3 − 4 orders of magnitude after 106− 107years. This mechanism explains the low magnetic fields of many pulsars entering binary systems.However, there exist both low–mass (e.g. Her X–1, 4U 1626–67) and high–mass (e.g. Cen X–3, SMC X–1) systems, where the neutron star deserves strong accretion and the magnetic field is still large.

Conditions for jet formation in accreting neutron stars: the magnetic field decay

2010 ◽  
Vol 6 (S275) ◽  
pp. 309-310
Author(s):  
Federico García ◽  
Deborah N. Aguilera ◽  
Gustavo E. Romero
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Neutron Stars ◽  
Compact Objects ◽  
Jet Formation ◽  
Field Diffusion ◽  
Induction Equation ◽  
Strong Surface ◽  
Field Decay ◽  
The Magnetic Field

AbstractAccreting neutron stars can produce jets only if they are weakly magnetized (B ~ 108 G). On the other hand, neutron stars are compact objects born with strong surface magnetic fields (B ~ 1012 G). In this work we study the conditions for jet formation in a binary system formed by a neutron star and a massive donor star once the magnetic field has decayed due to accretion. We solve the induction equation for the magnetic field diffusion in a realistic neutron star crust and discuss the possibility of jet launching in systems like the recently detected Supergiant Fast X-ray Transients.

scholarly journals SUPERNOVAE, LANDAU LEVELS, AND PULSAR KICKS

2007 ◽  
Vol 22 (25n28) ◽  
pp. 2071-2080 ◽  
Author(s):  
LEONARD S. KISSLINGER
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Strong Magnetic Field ◽  
Landau Levels ◽  
The Magnetic Field ◽  
Urca Process ◽  
Proto Neutron Star ◽  
Energy Asymmetry ◽  
Neutrino Momentum

We derive the energy asymmetry given the proto-neutron star during the time when the neutrino sphere is near the surface of the proto-neutron star, using the modified URCA process. The electrons produced with the anti-neutrinos are in Landau levels due to the strong magnetic field, and this leads to asymmetry in the neutrino momentum, and a pulsar kick. Our main prediction is that the large pulsar kicks start at about 10 s and last for about 10 s, with the corresponding neutrinos correlated in the direction of the magnetic field.

scholarly journals Finite Element Analysis of Magnetic Field Exciter for Direct Testing of Magnetocaloric Materials’ Properties

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2792
Author(s):  
Wieslaw Lyskawinski ◽  
Wojciech Szelag ◽  
Cezary Jedryczka ◽  
Tomasz Tolinski
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Magnetic Circuit ◽  
Homogeneous Magnetic Field ◽  
Element Analysis ◽  
Mcm Testing ◽  
Testing Region ◽  
Magnetocaloric Materials ◽  
Field Excitation ◽  
The Magnetic Field

The paper presents research on magnetic field exciters dedicated to testing magnetocaloric materials (MCMs) as well as used in the design process of magnetic refrigeration systems. An important element of the proposed test stand is the system of magnetic field excitation. It should provide a homogeneous magnetic field with a controllable value of its intensity in the MCM testing region. Several concepts of a magnetic circuit when designing the field exciters have been proposed and evaluated. In the MCM testing region of the proposed exciters, the magnetic field is controlled by changing the structure of the magnetic circuit. A precise 3D field model of electromagnetic phenomena has been developed in the professional finite element method (FEM) package and used to design and analyze the exciters. The obtained results of the calculations of the magnetic field distribution in the working area were compared with the results of the measurements carried out on the exciter prototype. The conclusions resulting from the conducted research are presented and discussed.

scholarly journals Effect of magnetic field on the burning of a neutron star

2018 ◽  
Vol 27 (10) ◽  
pp. 1850083 ◽  
Author(s):  
Ritam Mallick ◽  
Amit Singh
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Initial Density ◽  
Considerable Effect ◽  
Magnetic Axis ◽  
Small Window ◽  
Exothermic Process ◽  
Text Density ◽  
The Magnetic Field ◽  
Observational Aspect

In this paper, we present the effect of a strong magnetic field in the burning of a neutron star (NS). We have used relativistic magneto-hydrostatic (MHS) conservation equations for studying the PT from nuclear matter (NM) to quark matter (QM). We found that the shock-induced phase transition (PT) is likely if the density of the star core is more than three times nuclear saturation ([Formula: see text]) density. The conversion process from NS to quark star (QS) is found to be an exothermic process beyond such densities. The burning process at the star center most likely starts as a deflagration process. However, there can be a small window at lower densities where the process can be a detonation one. At small enough infalling matter velocities the resultant magnetic field of the QS is lower than that of the NS. However, for a higher value of infalling matter velocities, the magnetic field of QM becomes larger. Therefore, depending on the initial density fluctuation and on whether the PT is a violent one or not the QS could be more magnetic or less magnetic. The PT also have a considerable effect on the tilt of the magnetic axis of the star. For smaller velocities and densities the magnetic angle are not affected much but for higher infalling velocities tilt of the magnetic axis changes suddenly. The magnetic field strength and the change in the tilt axis can have a significant effect on the observational aspect of the magnetars.

ORIENTATION DYNAMICS OF MAGNETORHEOLOGICAL FLUIDS SUBJECT TO ROTATING EXTERNAL FIELDS

2001 ◽  
Vol 15 (06n07) ◽  
pp. 758-766 ◽  
Author(s):  
SONIA MELLE ◽  
MIGUEL A. RUBIO ◽  
GERALD G. FULLER
Keyword(s):  
Magnetic Field ◽  
Light Scattering ◽  
Simple Model ◽  
Critical Frequency ◽  
Optical Methods ◽  
Phase Lag ◽  
Rotating Magnetic Fields ◽  
Mr Fluids ◽  
Small Angle Light Scattering ◽  
The Magnetic Field

The formation and orientation of field-induced structures in magnetorheological (MR) fluids subject to rotating magnetic fields have been studied using two optical methods: scattering dichroism and small angle light scattering (SALS). The SALS patterns show how these chain-like aggregates follow the magnetic field with the same frequency but with a retarded phase angle for all the frequencies measured. Using scattering dichroism two different behaviors for both, dichroism and phase lag, are found below or above a critical frequency. Experimental results have been reproduced by a simple model considering the torques balance on the chain-like aggregates.

scholarly journals Mutual influence of magnetic field decay and thermal evolution of rotational neutron stars

2012 ◽  
Vol 8 (S291) ◽  
pp. 586-588
Author(s):  
Xia Zhou ◽  
Miao Kang ◽  
Na Wang
Keyword(s):  
Magnetic Field ◽  
Neutron Stars ◽  
Mutual Influence ◽  
Thermal Evolution ◽  
Chemical Heating ◽  
Field Decay ◽  
The Magnetic Field

AbstractThe effect of magnetic field decay on the chemical heating and thermal evolution of neutron stars is discussed. Our main goal is to study how chemical heating mechanisms and thermal evolution are changed by field decay and how magnetic field decay is modified by the thermal evolution. We show that the effect of chemical heating is suppressed by the star spin-down through decaying magnetic field at a later stage; magnetic field decay is delayed significantly relative to stars cooling without heating mechanisms; compared to typical chemical heating, the decay of the magnetic field can even cause the temperature to turn down at a later stage.

scholarly journals Recent Ginga Results on Galactic X-Ray Binaries

1992 ◽  
Vol 9 ◽  
pp. 211-215
Author(s):  
Y. Tanaka
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Related Problem ◽  
X Ray ◽  
Field Decay ◽  
X Ray Binaries ◽  
The Magnetic Field ◽  
Black Hole Candidates

AbstractBased on the recent Ginga results, following topics on X-ray binaries are briefly discussed: The cyclotron resonnance features observed from several X-ray pulsars, and related problem of the magnetic field decay. Search for millisec. pulsations from LMXRBs. Very bright transients which are suspected to be new black hole candidates, and an estimation of the number of such black hole sources in our galaxy.

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