共查询到20条相似文献，搜索用时 15 毫秒
1.
J. B. Singh 《Astrophysics and Space Science》1983,93(1):15-23
In this paper self-similar solutions have been investigated for the propagation of axisymmetric radiative gasdynamic shocks caused by an explosion into an inhomogeneous ideal gas permeated by a current free azimuthal magnetic field. The effects of radiation flux and magnetic field together have been seen in the region of interest on the other flow variables. The total energy of the flow between the inner expanding surface and the shock is taken to be dependent on shock radius obeying a power law. The radiative pressure and energy have been neglected. 相似文献
2.
In the present paper self-similar solutions have been investigated for the propagation of piston driven, radiative gas-dynamic shocks into an inhomogeneous ideal gas permeated by a current free azimuthal magnetic field for spherical symmetry. The effects of radiation flux and magnetic field together have been seen in the region of interest on the other flow variables. The total energy of the flow between the piston and the shock is taken to be dependent on the shock radius obeying a power law. The radiative pressure and energy have been neglected. This problem is more general than the others done so far. The word piston implies some means to drive plasma radially onwards. 相似文献
3.
Self-similar motion of a perfect gas behind a cylindrical shock wave with radiation heat flux in the presence of an azimuthal magnetic field have been discussed. The shock is assumed to be propagating in a medium at rest with non-uniform density. The conductivity of the gas is infinite and magnetic permeability is one everywhere. Also, the shock is assumed to be transparent and isothermal. 相似文献
4.
The magnetohydrodynamic model of shock waves has been discussed in an atmosphere with gravitation and radiation. The disturbance is headed by a strong shock of increasing density. The medium ahead of the shock is assumed to be inhomogeneous and at rest. Variation of magnetic field radiation flux, and other flow variables are given in tabular form. 相似文献
5.
Similarity solutions describing the flow of a perfect gas behind a spherical and cylindrical shock wave in a magnetic field with radiation heat flux have been investigated. The total energy of the expanding wave has been assumed to remain constant. The solutions, however, are only applicable to a gaseous medium where the undisturbed pressure falls as the inverse square of the distance from the line of explosion. 相似文献
6.
An exact similarity solution for a spherical magnetogasdynamic shock is obtained in the case when radiation energy, radiation pressure and radiative heat flux are important. The total energy of the shock wave increase with time. We have shown that due to the magnetic field the flow variables are considerably changed. Also, due to increases in radiation pressure number the radiation flux is increased. 相似文献
7.
S. N. Ojha 《Astrophysics and Space Science》1987,135(1):175-185
Similarity solutions for one-dimensional unsteady isothermal flow of a perfect gas behind a magnetogasdynamic shock wave including the effects of thermal radiation has been investigated in a uniform thin atmosphere. The flow is caused by an expanding piston and the total energy of the flow is assumed to be constant. Radiation pressure and energy have been neglected in comparison to radiation heat flux and the gas is assumed to be grey and opaque. 相似文献
8.
The effect of radiation up on the state of gas behind strong M.H.D. shock front has been studied. The jump conditions for flow variables across the shock boundary have been obtained and temperature decay behind the shock front is determined for a optically-thin brehmsstrahlung radiation plasma. It has been found that, for a shock within strong magnetic field, the temperature decay is much quicker. 相似文献
9.
S. N. Ojha 《Astrophysics and Space Science》1987,138(2):303-313
Similarity solutions describing the flow of a perfect gas behind a strong plane shock wave propagating in an exponentially decreasing atmosphere with radiation heat flux are investigated. The Planck's diffusion approximation has been taken into account to observe the effects of radiation heat flux. 相似文献
10.
Y. E. Lyubarsky 《Monthly notices of the Royal Astronomical Society》2003,345(1):153-160
The origin of radio emission from plerions is considered. Recent observations suggest that radio-emitting electrons are presently accelerated rather than having been injected at early stages of the plerion evolution. The observed flat spectra without a low-frequency cut-off imply an acceleration mechanism that raises the average particle energy by orders of magnitude but leaves most of the particles at an energy of less than approximately a few hundred MeV. It is suggested that annihilation of the alternating magnetic field at the pulsar wind termination shock provides the necessary mechanism. Toroidal stripes of opposite magnetic polarity are formed in the wind emanating from an obliquely rotating pulsar magnetosphere (the striped wind). At the termination shock, the flow compresses and the magnetic field annihilates by driven reconnection. Jump conditions are obtained for the shock in a striped wind. It is shown that the post-shock magnetohydrodynamic parameters of the flow are the same as if the energy of the alternating field had already been converted into plasma energy upstream of the shock. Therefore, the available estimates of the ratio of the Poynting flux to the matter energy flux, σ, should be attributed not to the total upstream Poynting flux but only to that associated with the average magnetic field. A simple model for the particle acceleration in the shocked striped wind is presented. 相似文献
11.
Similarity solutions describing the flow of a perfect gas behind a cylindrical shock wave with transverse magnetic field are investigated in an inhomogeneous medium. The total energy of the shock wave is assumed to be constant. A comparative study has been made between the results with and without magnetic field. 相似文献
12.
Self-similar MHD shock waves have been studied under the action of monochromatic radiation into a non-uniform stellar atmosphere with a constant intensity on unit area. It has been assumed that the radiation flux moves through the gas. Variation of flow variables have heen shown in tables for two different cases. 相似文献
13.
The growth of weak MHD discontinuities have been studied in a radiation induced flow field at very high temperature. Growth and decay properties of weak MHD discontinuities have been discussed under the influences of time-dependent gasdynamic field, the radiation field and the magnetic field with finite electrical conductivity. The effects of thermal radiation and conduction of the global behaviour of weak MHD discontinuities have been studied under a quasi-equilibrium and quasi-isotropic hypothesis of the differential approximation to the radiative heat transfer equation. It is shown that the existence of the time-dependent radiation field gives rise to a radiation induced wave which has a negligibly small effect on the non-relativistic flow properties of the gasdynamic field. It is also shown that the radiation stresses resist the steepening tendency of a compressive weak wave and help in stabilizing it whereas the thermal conduction effects counteracts to destabilize it. It is found that under radiation effects the shock formation is either disallowed or delayed. The two cases of diverging waves and converging waves have been studied separately to answer a particular question as to when a shock discontinuity or a coustic will be formed or disallowed under curvature effects. 相似文献
14.
An exact similarity solution for a spherical magneto-gas dynamic shock wave is obtained in the case when the loss of energy due to radiation escape is significant. The total energy of the shock wave is not constant but decreases with time. We have shown that due to the magnetic field, the radiation flux changes considerably. 相似文献
15.
An exact solution for a spherically-symmetric model of a magneto-radiative shock wave in the solar wind caused by the explosive
energy release of a solar flare has been, obtained in the case when energy released is an increasing function of the time.
It has been shown that due to increasing energy, density, pressure, radiation flux, magnetic field and shock velocity change
considerably. 相似文献
16.
The propagation of plane magnetogasdynamic shock waves in an optically-thin grey atmosphere of non-uniform density has been discussed by the use of the similarity method, by use of Planck's diffusion approximation. The distribution of pressure, density, magnetic field, velocity, temperature, and radiation flux have been illustrated through graphs. The numerical integration has been done on a DEC-1090 computer under a RKGS programme. 相似文献
17.
A theoretical model of shock-wave propagation has been studied in a heat-conducting and a self-gravitating medium. The effects of magnetic field has been taken into consideration. The shock is strong enough to neglect the ambient gas pressure. The variation of flow variables behind the shock have been investigated numerically. 相似文献
18.
A self-similar flow of a perfect gas behind a strong shock driven out by a propelling contact discontinuity surface moving with time according to an exponential law in the presence of axial component of the magnetic field is investigated. The flow between the shock and the inner-expanding surface is assumed to be isothermal. The infinite electrically conductive and uniform medium has been taken into consideration. 相似文献
19.
Similarity solutions, describing the flow of a perfect gas behind spherical shock waves, are investigated including the radiation heat flux. The shock is assumed to be propagating in a medium at rest. Shock radius varies exponentially with time and density is inversely proportional to fifth power of the shock radius immediately ahead of the shock front. 相似文献
20.
Similarity solutions have been obtained for a cylindrical piston advancing with constant speed into a uniform plasma of infinite electrical conductivity and uniform axial magnetic field with heat radiation. The total energy of the expanding wave has been supposed to remain constant. The plasma is assumed to be a perfect grey gas in local thermodynamic equilibrium. To make the discussions less complicated the simplifying assumptions include transparent shock, cool piston neither an emitter nor a reflector and negligible radiation pressure and energy.This research was partially supported by a grant from U.G.C., India. 相似文献