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1.
The nonstationary dynamics of vortices in conventional type II superconductors and in neutron stars is examined in the Newtonian
approximation. A relaxation equation is obtained for vortices approaching an equilibrium distribution after a change in an
external magnetic field. The relaxation times are estimated for vortices in low-temperature superconductors and for proton
vortices in the superconducting core of a neutron star. It is shown that the proton vortex system created by entrainment currents
is rigidly coupled to the neutron vortices.
Translated from Astrofizika, Vol. 52, No. 2, pp. 291–300 (May 2009). 相似文献
2.
The superfluid core (“npe” phase) of a neutron star, consisting of superfluid neutrons, superconducting protons, and normal
electrons, is considered. The Gibbs thermodynamic potential of a superconducting proton vortex in a proton superconductor
of the second kind, interacting with the normal core of a neutron vortex of radius r ≪ λ parallel to it (λ is the depth of
penetration), is calculated. It is shown that under this assumption, the capture by the core of only one vortex turns out
to be energetically favored. The force exerted on the proton vortex by the entrainment current, always directed toward the
core, is found. The corresponding force for a proton antivortex is directed outward toward the outer boundary of the neutron
vortex. It is shown that the fluctuational formation of a vortex-antivortex pair is possible at a large distance from the
core under the action of the entrainment current. Under the action of the entrainment current, the antivortex travels outward,
while the vortex remains inside the neutron vortex. It is shown that the formation of new proton vortices is possible only
in the region in which the entrainment magnetic field strength is H(ρ) > Hcl (Hcl is the first critical field).
Translated from Astrofizika, Vol. 42, No. 2, pp. 225–234, April–June, 1999 相似文献
3.
The vortex structure of the “npe” phase of neutron stars with a 3P2 superfluid neutron condensate of Cooper pairs is discussed. It is shown that, as the star rotates, superfluid neutron vortex
filaments described by a unitary ordering parameter develop in the “npe” phase. The entrainment of superconducting protons
by the rotating superfluid neutrons is examined. The entrainment effect leads to the appearance of clusters of proton vortices
around each neutron vortex and generates a magnetic field on the order of 1012 G. 3P2 neutron vortex filaments combine with quark semi-superfluid vortex filaments at the boundary of the “npe” and “CFL” phases.
At the boundary of the “Aen” and “npe” phases, they combine with 1S0 neutron vortex filaments. In this way, a unified vortex structure is formed. The existence of this structure and its collective
elastic oscillations explain the observed oscillations in the angular rotation velocity of pulsars. 相似文献
4.
The Ginzburg-Landau equations are derived for the magnetic and gluomagnetic gauge fields in the color superconducting core
of a neutron star containing a CFL-condensate of diquarks. The interaction of the diquark CFL-condensate with the magnetic
and gluomagnetic gauge fields is taken into account. The behavior of the magnetic field in a neutron star is studied by solving
the Ginzburg-Landau equations taking correct account of the boundary conditions, including the gluon confinement conditions.
The magnetic field distribution in the quark and hadronic phases of a neutron star is found. It is shown that a magnetic field
generated in the hadronic phase by the entrainment effect penetrates into the quark core in the form of quark vortex filaments
because of the presence of screening Meissner currents.
__________
Translated from Astrofizika, Vol. 50, No. 1, pp. 87–98 (February 2007). 相似文献
5.
The Ginzburg-Landau equations are derived for the magnetic and gluomagnetic gauge fields of nonabelian semi-superfluid vortex
filaments in color superconducting cores of neutron stars containing a diquark CFL condensate. The interaction of the diquark
CFL condensate with the magnetic and gluomagnetic gauge fields is taken into account. The asymptotic values of the energies
of these filaments are determined from the quantization conditions. It is shown that a lattice of semi-superfluid vortex filaments
with a minimal quantum of circulation develops in the quark superconducting core during rotation of the star. The magnetic
field in the core of this vortex is on the order of 1018 G. A cluster of proton vortices, which develops in the hadron phase surrounding every superfluid neutron vortex owing to
an entrainment effect, creates new semi-superfluid vortex filaments with a minimal quantum of circulation in the quark superconducting
core.
Translated from Astrofizika, Vol. 51, No. 4, pp. 633–646 (November 2008). 相似文献
6.
N. Andersson T. Sidery G. L. Comer 《Monthly notices of the Royal Astronomical Society》2006,368(1):162-170
We discuss vortex-mediated mutual friction in the two-fluid model for superfluid neutron star cores. Our discussion is based on the general formalism developed by Carter and collaborators, which makes due distinction between transport velocity and momentum for each fluid. This is essential for an implementation of the so-called entrainment effect, whereby the flow of one fluid imparts momentum in the other and vice versa. The mutual friction follows by balancing the Magnus effect that acts on the quantized neutron vortices with resistivity due to the scattering of electrons off of the magnetic field with which each vortex core is endowed. We derive the form of the macroscopic mutual friction force which is relevant for a model based on smooth-averaging over a collection of vortices. We discuss the coefficients that enter the expression for this force, and the time-scale on which the two interpenetrating fluids in a neutron star core are coupled. This discussion confirms that our new formulation accords well with previous work in this area. 相似文献
7.
The magnetic field distribution in the superfluid, spherical, hadronic core of a rotating neutron star, which consists of vortex and vortex-free zones, is investigated. Due to the effect of entrainment of superconducting protons by rotating superfluid neutrons, a nonuniform magnetic field, the average value of which is constant, is formed in the vortex zone of the neutron star, directed parallel to the star's axis of rotation. It is shown that at the stellar surface, near the equatorial plane, there is a vortex-free zone of macroscopic size in which there is no magnetic field. The magnetic field near the boundaries of the vortex-free zone falls off exponentially with depth into the interior of this zone. This result essentially alters earlier concepts about the magnetic field distribution in the superfluid hadronic core of a neutron star. Outside the hadronic core the magnetic field has a dipole character with a magnetic moment on the order of 1030 g×cm3. 相似文献
8.
The effect of proton superconductivity on the generation of a toroidal magnetic field inside a neutron star is examined. It
is shown that including the entrainment of superconducting protons by superfluid neutrons does not change the previously obtained
results. Proton superconductivity does influence the structure of the generated magnetic field since, over a time on the order
of 104–105 years, the magnetic field increases linearly with time and can exceed the first critical field for proton superconductivity.
The distribution of the stationary toroidal magnetic field inside a neutron star is also found. 相似文献
9.
Fluctuational mechanism for the formation of proton vortices in the superfluid core of neutron stars
The Gibbs thermodynamic potential of a proton vortex interacting with the normal core of a neutron vortex of radius r << λ (λ is the penetration depth) that is parallel to it and has an outer boundary of radius b is calculated. It is shown that, under
this assumption, the capture of only one vortex by the core is energetically favorable. The force acting on the proton vortex
owing to the entrained current is found and it is always directed toward the core. The corresponding force for a proton antivortex
is directed toward the outer boundary of the neutron vortex. The Ginzburg-Landau equation is solved for a vortex-antivortex
system and its Gibbs function is calculated. It is shown that at large distances from the core, vortex-antivortex pairs can
form because of fluctuations. Acted on by the entrainment current, the antivortex moves outward, while the vortex stays inside
the neutron vortex. It is shown that the best conditions for fluctuational pair production, followed by separation, exist
near the outer boundary. It is shown that new proton vortices can develop only in a region where the entrainment magnetic
field strength H (ρ) > HC1 (HC1 is the lower critical field).
__________
Translated from Astrofizika, Vol. 51, No. 1, pp. 139–149 (February 2008). 相似文献
10.
P. B. Jones 《Monthly notices of the Royal Astronomical Society》2006,371(3):1327-1333
Neutron star inner cores with several charged baryonic components are likely to be analogues of the two-gap superconductor which is of current interest in condensed-matter physics. Consequently, type I superconductivity is less probable than type II but may nevertheless be present in some intervals of matter density. The intermediate-state structure formed at finite magnetic flux densities after the superconducting transitions is subject to buoyancy, frictional and neutron vortex interaction forces. These are estimated and it is shown that the most important frictional force is that produced by the stable stratification of neutron star matter, the irreversible process being diffusion in the normal, finite magnetic flux density, parts of the structure. The length-scale of the structure, in directions perpendicular to the local magnetic field is of crucial importance. For small scales, the flux comoves with the neutron vortices, as do the proton vortices of a type II superconductor. But for much larger length-scales, flux movement tends to that expected for normal charged Fermi systems. 相似文献
11.
Dipankar Bhattacharya 《Journal of Astrophysics and Astronomy》1995,16(2):217-232
Observational evidence, and theoretical models of the magnetic field evolution of neutron stars is discussed. Observational
data indicates that the magnetic field of a neutron star decays significantly only if it has been a member of a close interacting
binary. Theoretically, the magnetic field evolution has been related to the processing of a neutron star in a binary system
through the spin evolution of the neutron star, and also through the accretion of matter on the neutron star surface. I describe
two specific models, one in which magnetic flux is expelled from the superconducting core during spin-down, via a copuling
between Abrikosov fluxoids and Onsager-Feynman vortices; and another in which the compression and heating of the stellar crust
by the accreted mass drastically reduces the ohmic decay time scale of a magnetic field configuration confined entirely to
the crust. General remarks about the behaviour of the crustal field under ohmic diffusion are also made. 相似文献
12.
The behaviour of the magnetic field of a neutron star with a superconducting quark matter core is investigated in the framework of the Ginzburg-Landau theory. We take into account the simultaneous coupling of the diquark condensate field to the usual magnetic and to the gluomagnetic gauge fields. We solve the Ginzburg-Landau equations by properly taking into account the boundary conditions, in particular, the gluon confinement condition. We found the distribution of the magnetic field in both the quark and hadronic phases of the neutron star and show that the magnetic field penetrates into the quark core in the form of quark vortices due to the presence of Meissner currents. 相似文献
13.
Armen Sedrakian James M. Cordes 《Monthly notices of the Royal Astronomical Society》1999,307(2):365-375
We show that the crust–core interface in neutron stars acts as a potential barrier to the peripheral neutron vortices approaching the interface in the model in which these are coupled to the proton vortex clusters. This elementary barrier arises because of the interaction of vortex magnetic flux with the Meissner currents set up by the crustal magnetic field at the interface. The dominant part of the force is derived from the cluster–interface interaction. As a result of the stopping of the continuous neutron vortex current through the interface, angular momentum is stored in the superfluid layers in the vicinity of the crust–core interface during the interglitch period. Discontinuous annihilation of proton vortices at the boundary restores the neutron vortex current and spins up the observable crust on short time-scales, leading to a glitch in the spin characteristics of a pulsar. 相似文献
14.
Jones 《Monthly notices of the Royal Astronomical Society》1998,296(1):217-224
It is usually assumed that pulsar glitches are caused by the large-scale unpinning of superfluid neutron vortices in the solid crust of a neutron star and that vortex motion relative to the crust is highly dissipative at low velocities, owing to the excitation of long-wavelength Kelvin waves. The force per unit length acting on a vortex as a result of Kelvin wave excitation has been calculated for a polycrystalline structure using the free-vortex Green function. An approximate upper limit for the maximum pinning force has been obtained which, for the form of structure anticipated, is many orders of magnitude too small for consistency with the observed size and frequency of glitches. The corollary is that glitches do not originate in the crust: the necessary pinning may be given by the interaction between neutron and proton vortices in the liquid core of the star. 相似文献
15.
Feynman's approach has been used to derive the equation of dynamics for type II superconductors from the Schr?dinger equation.
A closed set of equations for the study of vortex dynamics has been obtained. These equations have been used for calculating
electric and magnetic fields inside the core of neutron stars. In particular, the contribution of vortices to the generation
of electric and magnetic fields inside the core of the star is explicitly displayed. 相似文献
16.
The superconducting proton condensate in the “npe” phase of a neutron star is considered. It is shown to be a type II superconductor
in the outer layer of the “npe” phase and a type I superconductor in the inner layer. Relaxation times are found for elastic
scattering of normal relativistic electrons from the magnetic fields of proton vortex clusters in the case of a type II superconductor
and elastic scattering from the magnetic field at the center of a neutron vortex in the case of a superconductor of the first
kind. The dynamical relaxation times obtained for the angular velocity of the pulsar PSR 0833—45 vary, as a function of the
density of the layers taking part in the relaxation process, within a fairly wide range: from several hours to l09 years. This means that the characteristic times of variation of pulsar angular velocity may be observed to lie in the indicated
time range.
Translated from Astrofizika, Vol. 40, No. 4, op. 497–506, October–December, 1997. 相似文献
17.
Edward P. J. Van den Heuvel 《Journal of Astrophysics and Astronomy》1984,5(3):209-233
The peculiar combination of a relatively short pulse period and a relatively weak surface dipole magnetic field strength of
binary radio pulsars finds a consistent explanation in terms of (i) decay of the surface dipole component of neutron-star
magnetic fields on a timescale of (2–5) × 106 yr, in combination with (ii) spin-up of the rotation of the neutron star during a subsequent mass-transfer phase.
The four known binary radio pulsars appear to fall into two different categories. Two of them, PSR 0655 + 64 and PSR 1913
+ 16, have short orbital periods (<25 h) and high mass functions, indicating companion masses 0.7M⊙ (∼1 (± 0.3) M⊙ and 1.4 M⊙, respectively). The other two, PSR 0820 + 02 and PSR 1953 + 29, have long orbital periods (117d),
nearly circular orbits, and low, almost identical mass functions of about 3×10-3 M⊙, suggesting companion masses of about 0.3M⊙. It is pointed out that these two classes of systems are expected to be formed by the later evolution of binaries consisting
of a neutron star and a normal companion star, in which the companion was (considerably) more massive than the neutron star,
or less massive than the neutron star, respectively. In the first case the companion of the neutron star in the final system
will be a massive white dwarf, in a circular orbit, or a neutron star in an eccentric orbit. In the second case the final
companion to the neutron star will be a low-mass (∼ 0.3 M⊙) helium white dwarf in a wide and nearly circular orbit.
In systems of the second type the neutron star was most probably formed by the accretion-induced collapse of a white dwarf.
This explains in a natural way why PSR 1953 + 29 has a millisecond rotation period and PSR 0820 + 02 has not.
Among the binary models proposed for the formation of the 1.5-millisecond pulsar, the only ones that appear to be viable are
those in which the companion disappeared by coalescence with the neutron star. In such models the companion may have been
a red dwarf of mass 0.03M⊙, a neutron star, or a massive (>0.7M⊙) white dwarf. Only in the last-mentioned case is a position of the pulsar close to the galactic plane a natural consequence.
In the first-mentioned case the progenitor system most probably was a cataclysmic-variable binary in which the white dwarf
collapsed by accretion. 相似文献
18.
S. I. Bastrukov H.-K. Chang I. V. Molodtsova E.-H. Wu G.-T. Chen S.-H. Lan 《Astrophysics and Space Science》2009,323(3):235-242
Using the energy variational method of magneto-solid-mechanical theory of a perfectly conducting elastic medium threaded by
magnetic field, the frequency spectrum of Lorentz-force-driven global torsional nodeless vibrations of a neutron star with
Ferraro’s form of axisymmetric poloidal nonhomogeneous internal and dipole-like external magnetic field is obtained and compared
with that for this toroidal Alfvén mode in a neutron star with homogeneous internal and dipolar external magnetic field. The
relevance of considered asteroseismic models to quasi-periodic oscillations of the X-ray flux during the ultra powerful outbursts
of SGR 1806−20 and SGR 1900+14 is discussed. 相似文献
19.
K. Glampedakis N. Andersson D. I. Jones 《Monthly notices of the Royal Astronomical Society》2009,394(4):1908-1924
We discuss short wavelength (inertial wave) instabilities present in the standard two-fluid neutron star model when there is sufficient relative flow along the superfluid neutron vortex array. We demonstrate that these instabilities may be triggered in precessing neutron stars, since the angular velocity vectors of the neutron and proton fluids are misaligned during precession. Our results suggest that the standard (Eulerian) slow precession that results for weak drag between the vortices and the charged fluid (protons and electrons) is not seriously affected by the instability. In contrast, the fast precession, which results when vortices are strongly coupled to the charged component, is generally unstable. The presence of this instability renders the standard (solid body) rotation model for free precession inconsistent and makes unsafe conclusions that have recently been drawn regarding neutron star interiors based on observations of precession in radio pulsars. 相似文献
20.
The applications of the spectral analysis methods discovered by Kirchhoff for the investigation of stellar magnetic fields
are considered. The statistical properties of the mean magnetic fields for OBA stars have been investigated by analyzing data
from two catalogs of magnetic fields. It is shown that the mean effective magnetic field ℬ of a star can be used as a statistically
significant characteristic of its magnetic field. The magnetic field distribution functions F(ℬ) have been constructed for B-type and chemically peculiar (CP) stars, which exhibit a power-law dependence on ℬ. A sharp
decrease in F(ℬ) in the range of weak magnetic fields has been found. The statistical properties of the magnetic fluxes for main-sequence
stars, white dwarfs, and neutron stars are analyzed. 相似文献