共查询到20条相似文献，搜索用时 46 毫秒
1.
The stability of an inhomogeneous anisotropic plasma flowing along a straight magnetic field has been investigated. Both the flow velocity and the plasma density are spatially varying in a direction perpendicular to the magnetic field. The stability of an interface between an inhomogeneous anisotropic plasma flowing along the magnetic field and the non-conducting compressible gas of uniform density flowing parallel to the interface has also been discussed. The effect of gyroviscosity and inhomogeneity on the Kelvin-Helmholtz shear instability has been discussed in certain limiting situations. 相似文献
2.
A general solution of cylindrical symmetry in which distribution consists of an electrically neutral viscous fluid with an infinite electrical conductivity in presence of magnetic field, has been obtained. The behaviour of magnetic field on the model has been clearly interpreted. Various physical and geometrical properties have also been discussed. 相似文献
3.
In the present paper, we have considered turbulent flow of an incompressible, viscous fluid which is nearly isotropic with an extra vector argument (i.e. rotational symmetry) and spatially homogeneous. The expression for acceleration covariance in presence of Coriolis force has been derived and solution has been obtained in terms of defining scalars. 相似文献
4.
The classical Rayleigh problem has been extended to the case of the hydromagnetic free-convective flow of an electrically-conducting and incompressible viscous fluid past an infinite vertical naturally permeable wall in a rotating system. The applied transverse magnetic field is fixed with the moving wall and the magnetic Reynolds number of the flow is taken small so that the induced magnetic field can be neglected in comparison to the applied magnetic field. The permeable wall starts moving from rest in the still fluid and thus arises an initial value problem whose solution has been obtained by the Laplace transform method for two important cases impulsive as well as accelerated start of the plate. Mathematical expression for skin friction components have been also obtained in a closed form. Asymptotic behaviour of the solution is analysed for both the cases, and some interesting particular cases have also been encountered. Influence of various physical parameters occurring into the problem has been discussed with the aid of graphs and tables. 相似文献
5.
Kelvin-Helmholtz instability of two superimposed fluids has been studied. One of the fluids is non-conducting and the other is conducting with finite resistivity. The fluids are assumed rotating and slipping past each other with a relative velocity. The neutral particles are also incorporated in one of the fluids of the system. A general dispersion relation has been derived and discussed under different conditions. The effect of rotation and the neutral particles, considering an infinitely-conducting system has also been analyzed and it is observed that small rotation and the presence of neutral particles destabilize the system. The effect of neutral particles is to decrease the effect of magnetic field, angular velocity, and the gravitational field. It has been found that an otherwise stable mode becomes overstable and grows exponentially in the presence of finite resistivity. 相似文献
6.
M. A. Vashkov’yak 《Solar System Research》2016,50(6):390-401
The problem of the secular perturbations of the orbit of a test satellite with a negligible mass caused by the joint influence of the oblateness of the central planet and the attraction by its most massive (or main) satellites and the Sun is considered. In contrast to the previous studies of this problem, an analytical expression for the full averaged perturbing function has been derived for an arbitrary orbital inclination of the test satellite. A numerical method has been used to solve the evolution system at arbitrary values of the constant parameters and initial elements. The behavior of some set of orbits in the region of an approximately equal influence of the perturbing factors under consideration has been studied for the satellite system of Uranus on time scales of the order of tens of thousands of years. The key role of the Lidov–Kozai effect for a qualitative explanation of the absence of small bodies in nearly circular equatorial orbits with semimajor axes exceeding ~1.8 million km has been revealed. 相似文献
7.
Strong cylindrical magnetogasdynamic shock waves in rotating interplanetary medium has been studied and an analytic solution for their propagation has been obtained. Using characteristic method and considering the effect of Coriolis force, we have shown that magnetic field has significant effect on the velocity of the shock wave. 相似文献
8.
Somenath Chakrabarty 《Astrophysics and Space Science》2008,314(1-3):105-112
The expulsion of magnetic flux lines from a growing superconducting core of a quark star has been investigated. The idea of
impurity diffusion in molten alloys and an identical mechanism of baryon number transport from hot quark-gluon-plasma phase
to hadronic phase during quark-hadron phase transition in the early universe, micro-second after big bang has been used. The
possibility of Mullins-Sekerka normal-superconducting interface instability has also been studied. 相似文献
9.
Considering the presence of electric field parallel to geomagnetic field in the magnetosphere, the problem of wave-particle interaction has been considered. Dispersion equation of whistler mode wave in presence of parallel electric field has been derived. Using the effective dispersion equation, the wave-particle interaction has been reformulated to account for the effect of parallel electric field. Using charged particle energy spectrum and magnetospheric field and plasma models, the flux of electron precipitation has been computed. It is shown that the parallel electric field plays an important role and may work in simultaneity with other processes known for enhancement of electron precipitation. 相似文献
10.
A. A. Abdullah 《Astrophysics and Space Science》1993,204(2):289-295
The problem of gravitational instability of an infinite homogenous fluid has been considered in the presence of a non-vertical magnetic field. A non-linear relation between the magnetic field and the magnetic induction proposed by P.H. Roberts (1981) in the context of neutron stars has been used. The dispersion relations have been obtained. It has been found that Jeans's criterion for instability is unaffected by this non-linear relationship even if the effect due to rotation is considered in the presence of a non-vertical magnetic field. 相似文献
11.
The instability in a horizontal layer of stratified compressible isotropic and anisotropic plasmas has been studied to include
simultaneously the effects of Coriolis forces and the finiteness of the ion Larmor radius. Using an integral approach, the
dispersion relation has been derived in both cases for plasmas having density stratified exponentially along the vertical.
The dispersion, relation has been solved numerically and it is found that both the FLR and Coriolis forces have stabilizing
influence on the instability in the isotropic plasmas. The same result is obtained for the case of anisotropic plasmas where
also the dispersion relation has been evaluated numerically. 相似文献
12.
R. K. Shevgaonkar 《Journal of Astrophysics and Astronomy》1986,7(4):275-292
Minimum-relative-entropy method (MREM) has been presented as a solution to the missing short-baseline problem in the synthesis
observations. It is shown that a measure of distance between the prior model and the image in the plane of pixel brightness
is an adequate measure of relative entropy. The method has been further extended for polarization observations and the potential
of the method against the conventional MEM has been demonstrated by simulated examples. 相似文献
13.
S. V. Sazonov 《Planetary and Space Science》1991,39(12):1667-1671
The non-linear regime of electrostatic perturbations of the equatorial ionospheric F-region generated by Rayleigh-Taylor instability has been discussed, taking into account conductivity along magnetic field lines. A closed non-linear equation has been derived in the stationary limit for the polarization electric field potential. It coincides with the Karman equation of an ideal liquid. To solve the equation, the averaged variational Whitham method has been proposed. Some solutions localized along and across the geomagnetic field, B, as well as quasi-periodic solutions in the transverse direction, have been investigated. Non-linear longitudinal localization of perturbations has been shown to be due to electron-ion collisions. 相似文献
14.
In this paper a self-similar motion in a medium of infinite electrical conductivity has been investigated in spherical symmetry under the influence of an idealized magnetic field and a comparison has been made of the state of flow variables with and without magnetic field. 相似文献
15.
The effect of finite conductivity on the Rayleigh-Taylor instability of an incompressible, viscous rotating fluid through a porous medium has been studied in the presence of a two-dimensional horizontal magnetic field. It has been shown that the solution is characterized by a variational principle. By making use of the existence of the variational principle, proper solutions have been obtained for a semi-infinite fluid in which density has a one-dimensional (exponential) vertical stratification. The dispersion relation has been derived and solved numerically. It is found that finite resistivity and porosity have a destabilizing effect on the Rayleigh-Taylor instability while rotation has a stabilizing effect. 相似文献
16.
Vinod Kumar Nagendra Kumar Krishna M. Srivastava R. C. Mittal 《Astrophysics and Space Science》1993,199(2):323-331
The problem of gravitational instability of an infinite homogeneous self-gravitating medium carrying a uniform magnetic field in the presence of Hall effect has been investigated to include the effect due to rotation. The dispersion relation has been obtained. It has been found that the Jeans's criterion for the instability remains unaffected even when the effect due to rotation is considered in the presence of Hall effect carrying a uniform magnetic. 相似文献
17.
N. Ibotombi Singh Y. Bembem Devi S. Surendra Singh 《Astrophysics and Space Science》2013,345(1):213-216
The effect of particle creation on the evolution of FRW cosmological model has been studied. The universe has been considered as an open thermodynamic system when particle creation leads to supplementary negative creation pressure in addition to the thermodynamic pressure. Dynamical behaviors of the cosmological solutions have been studied. 相似文献
18.
In this letter, we have considered a flat FRW universe. Instead of considering only one candidate for the dark energy, we
have considered the interaction between phantom field and modified Chaplygin gas. It has been shown that the potential of
the phantom field increases from a lower value with evolution of the universe. It has been observed that the field has an
increasing tendency and the potential has also an increasing tendency with passage of cosmic time. In the evolution of the
universe the crossing of w=−1 has been realized by this interacting model. 相似文献
19.
R. C. Sharma 《Astrophysics and Space Science》1974,29(1):L1-L4
The gravitational instability of an infinite homogeneous self-gravitating rotating plasma in the presence of a uniform vertical magnetic field has been studied to include the FLR effects. It has been found that the Jeans' criterion of instability remains unaffected even if rotation and FLR effects are included. The effect of rotation is to decrease the Larmor radius by an amount-depending upon the wavenumber of perturbation. The particular cases of the effect of FLR and rotation on the waves propagated along and perpendicular to the magnetic field have been discussed. 相似文献
20.
HR 8107, a reported new Be star, has been observed spectrophotometrically. The energy distribution curve of the star has been
compared with those of other stars of similar spectral and luminosity types and model atmospheres. On the basis of comparison
with model atmospheres an effective temperature has been assigned to the star 相似文献