Beam curvature in the magnetic field of a neutron star for an arbitrary angle between the magnetic dipole moment and incident beam

2003 ◽  
Vol 48 (12) ◽  
pp. 657-659 ◽  
Author(s):  
V. I. Denisov ◽  
I. P. Denisova ◽  
I. V. Krivchenkov ◽  
P. A. Vshivtseva
Keyword(s):  
Magnetic Field ◽  
Dipole Moment ◽  
Neutron Star ◽  
Magnetic Dipole ◽  
Magnetic Dipole Moment ◽  
Incident Beam ◽  
Arbitrary Angle ◽  
Beam Curvature ◽  
The Magnetic Field

The effect of a strongly stratified layer in the upper part of Mercury’s core on its magnetic field

2020 ◽  
Author(s):  
Patrick Kolhey ◽  
Daniel Heyner ◽  
Johannes Wicht ◽  
Karl-Heinz Glassmeier
Keyword(s):  
Magnetic Field ◽  
Dipole Moment ◽  
Magnetic Dipole ◽  
Magnetic Dipole Moment ◽  
Rotation Axis ◽  
Outer Core ◽  
Magnetic Field Generation ◽  
Fluid Core ◽  
Planetary Magnetic Fields ◽  
The Magnetic Field

<p>In the 1970’s the flybys of NASA’s Mariner 10 spacecraft confirmed the existence of an internally generated magnetic field at Mercury. The measurements taken during its flybys already revealed, that Mercury‘s magnetic field is unique along other planetary magnetic fields, since the magnetic dipole moment of ~190 nT ∙ R<sub>M</sub><sup>3 </sup>is very weak, e.g. compared to Earth’s magnetic dipole moment. The following MESSENGER mission from NASA investigated Mercury and its magnetic field more precisely and exposed additional interesting properties about the planet’s magnetic field. The tilt of its dipole component is less than 1°, which indicates a strong alignment of the field along the planet’s rotation axis. Additionally the measurement showed that the magnetic field equator is shifted roughly 0.2 ∙ R<sub>M</sub> towards north compared to Mercury‘s actual geographic equator.</p><p>Since its discovery Mercury‘s magnetic field has puzzled the community and modelling the dynamo process inside the planet’s interior is still a challenging task. Adapting the typical control parameters and the geometry in the models of the geodynamo for Mercury does not lead to the observed field morphology and strength. Therefore new non-Earth-like models were developed over the past decades trying to match Mercury’s peculiar magnetic field. One promising model suggests a stably stratified layer on the upper part of Mercury’s core. Such a layer divides the fluid core in a convecting part and a non-convecting part, where the magnetic field generation is mainly inhibited. As a consequence the magnetic field inside the outer core is damped very efficiently passing through the stably stratified layer by a so-called skin effect. Additionally, the non-axisymmetric parts of the magnetic field are vanishing, too, such that a dipole dominated magnetic is left at the planet’s surface.</p><p>In this study we present new direct numerical simulations of the magnetohydrodynamical dynamo problem which include a stably stratified layer on top of the outer core. We explore a wide parameter range, varying mainly the Rayleigh and Ekman number in the model under the aspect of a strong stratification of the stable layer. We show which conditions are necessary to produce a Mercury-like magnetic field and give a inside about the planets interior structure.</p>

scholarly journals About Bonnor Solution and Gravitational Redshift

2017 ◽  
Vol 45 ◽  
pp. 1760048
Author(s):  
Orlenys Troconis ◽  
Viviane Alfradique ◽  
Rodrigo Negreiros
Keyword(s):  
Dipole Moment ◽  
Neutron Star ◽  
Magnetic Fields ◽  
Magnetic Dipole ◽  
Maxwell Equations ◽  
Magnetic Dipole Moment ◽  
Polar Angle ◽  
Gravitational Redshift ◽  
Schwarzschild Solution ◽  
Emission Signal

We consider the analytical Bonnor solution for a relativistic neutron star and discuss about the limit in which this solution satisfies Einstein-Maxwell equations. We study the gravitational redshift for Bonnor solution without electric charge. We find that for stars with magnetic fields up to [Formula: see text] in the center, the gravitational redshift for Bonnor metric differs from the Schwarzschild solution on a term that depends on magnetic dipole moment and the polar angle of the emission signal.

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 Hydromagnetic Structure of a Neutron Star Accreting at Its Polar Caps

2001 ◽  
Vol 18 (4) ◽  
pp. 421-430 ◽  
Author(s):  
A. Melatos ◽  
E. S. Phinney
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Magnetic Dipole ◽  
Fractional Difference ◽  
Thin Boundary Layer ◽  
Polar Caps ◽  
Principal Moments Of Inertia ◽  
Equatorial Belt ◽  
Magnetic Poles ◽  
The Magnetic Field

AbstractThe hydromagnetic structure of a neutron star accreting symmetrically at both magnetic poles is calculated as a function of accreted mass, Ma, starting from a polytropic sphere plus central magnetic dipole (Ma =0) and evolving the configuration through a quasistatic sequence of twodimensional, Grad–Shafranov equilibria as Ma increases. It is found that the accreted material spreads equatorward under its own weight, compressing the magnetic field into a thin boundary layer and burying it everywhere except in a narrow, equatorial belt. The magnetic dipole moment of the star is given by µ=5.2×1024(B0/1012.5G)1.3(Ma/10−8Mʘ yr−1)0.18(Ma/Mʘ)−1.3Gcm3, and the fractional difference between its principal moments of inertia is given by Є=2.1×10−5(B0/1012.5G)0.27(Ma/10−8Myr−1)0.18(Ma/Mʘ)1.7, for Ma in the range 10−5Ma/Mʘ10−1,where B0 is the pre-accretion magnetic field strength, and Ma is the accretion rate.

scholarly journals Pseudospin versus magnetic dipole moment ordering in the isosceles triangular lattice material K3Er(VO4)2

2020 ◽  
Vol 102 (10) ◽  
Author(s):  
Danielle R. Yahne ◽  
Liurukara D. Sanjeewa ◽  
Athena S. Sefat ◽  
Bradley S. Stadelman ◽  
Joseph W. Kolis ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Magnetic Dipole ◽  
Triangular Lattice ◽  
Magnetic Dipole Moment ◽  
Lattice Material

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.

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