首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 156 毫秒
1.
. - . . , . - . - , , , -. ., , .
The structure of rotating magnetic polytropes is considered in Roche approximation. Investigation of the influence of poloidal as well as toroidal magnetic fields on the conditions of the beginning of matter outflow due to rotational instability is carried out. The influence of the turbulent convection and twisting of magnetic force-lines on the time of smoothing of differential rotation is considered. The estimate of the magneto-turbulence energy generated by differential rotation is presented. Both maximum possible energy output and duration of the quasi-statical evolution phase up to the appearance of hydrodynamic instability due to the effects of general relativity are calculated for supermassive magnetic polytropes of index three with uniform or differential rotation. The radius-mass relation is obtained for supermassive differentially-rotating magnetic polytropes referring to the longest part of the quasi-statistical evolution stage; some consequences are pointed out, including the period-luminosity relation.The evolution of the considered models of supermassive rotating magnetic polytropes with different character of rotation and different geometry of a magnetic field is discussed.The results obtained are summarized in the last section.

English translation will appear in the next issue ofAstrophys. Space Sci.

Receipt delayed by postal strike in Great Britain  相似文献   

2.
. , , . . . , . . - , , .  相似文献   

3.
E. W. Cliver 《Solar physics》1995,157(1-2):285-293
The evolution of solar flare nomenclature is reviewed in the context of the paradigm shift, in progress, from flares to coronal mass ejections (CMEs) in solar-terrestrial physics. Emphasis is placed on: the distinction between eruptive (Class II) flares and confined (Class I) flares; and the underlying similarity of eruptive flares inside (two-ribbon flares) and outside (flare-like brightenings accompanying disappearing filaments) of active regions. A list of research questions/problems raised, or brought into focus, by the new paradigm is suggested; in general, these questions bear on the interrelationships and associations of the two classes (or phases) of flares. Terms such as eruptive flare and eruption (defined to encompass both the CME and its associated eruptive flare) may be useful as nominal links between opposing viewpoints in the flares vs CMEs controversy.  相似文献   

4.
The applicability of the properties of central configurations proceeding from the many-body problem to study of gaseous sphere cloud evolution during its gravitational contraction is justified. It is shown that the product runs to a constant value in the asymptotic time limit of simultaneous collision of all the particles of the cloud where is a form-factor of the potential energy and is a form-factor of the moment of inertia.The spherical bodies as well as ellipsoids of rotation and general ellipsoids with a one-dimensional mass distribution (k),k[0, 1] are found to possess the property =const.
. , - , , ., , - =const., , (k),k[0, 1].
  相似文献   

5.
M. Dizer 《Solar physics》1969,10(2):416-428
We report measurements made on the brightness in H of all parts of the flare photographed through a birefringent filter centered on H, using a scanning isodensitometer. From obtained isophotes of the flares we derived some information on the morphological changes in the flare and estimated the total energy in H of the flare.  相似文献   

6.
Some particular solutions of the restricted three-body problem which determine outgoing or incoming orbits near libration points are considered. The solutions are obtained in the form of absolutely convergent Liapounov series. It is proved that these asymptotic solutions are plane curves situated in the orbital plane of the primaries. Each family of asymptotic solutions for every collinear point consists of four solutions which are the separatrices of a saddle point. The angles of inclination of the separatrices are determined.
aaa a a aa , a. a a a. a, a . . aa, a a aaa. . a . a a , aaa a. . aa aa a .
  相似文献   

7.
The HXIS, a joint instrument of the Space Research Laboratory at Utrecht, The Netherlands, and the Department of Space Research of the University of Birmingham, U.K., images the Sun in hard X-rays: Six energy bands in energy range 3.5–30 keV, spatial resolution 8 over Ø 240 and 32 over Ø 624 field of view, and time resolution of 0.5–7 s depending on the mode of operation. By means of a flare flag it alerts all the other SMM instruments when a flare sets in and informs them about the location of the X-ray emission. The experiment should yield information about the position, extension and spectrum of the hard X-ray bursts in flares, their relation to the magnetic field structure and to the quasi-thermal soft X-rays, and about the characteristics and development of type IV electron clouds above flare regions.  相似文献   

8.
We consider potential sources of infrared (1 to 1 mm) continuum in solar flares. Several mechanisms should produce detectable fluxes: in the 350 window for ground-based observations, impulsive emission will arise in synchrotron radiation from 1–10 MeV electrons, and possibly thermal (free-free) continuum from the source of the white-light flare; the hot flare plasma responsible for soft X-ray emission will also emit detectable fluxes of free-free continuum in the largest flares. At shorter wavelengths the dominant infrared emission will come from the H flare itself. Observations in the infrared wavelengths will help to complete our picture of flare structure in both the impulsive and gradual phases.  相似文献   

9.
Sunspot associated H-flares and microwave bursts occurring during the period 1972 to 1974 have been examined in relation to the magnetic strength and configurations of the sunspots and sunspot groups (abbreviated as spots). Important results obtained are: (i) percentage occurrences of flares exceeds those of microwave bursts up to a magnetic field strength of 2000 G while the reverse is true for higher field strength of spots, (ii) flare productivity (average number of flares per spot) and also burst productivity are comparatively higher in the case of and types of spots than in the case of other types of spots, (iii) the above productivities are predominantly high when magnetic configuration of spots changes during their life time, and (iv) impulsive type of microwave bursts are more associated with spots having changing type of magnetic configuration.  相似文献   

10.
High resolution H images obtained before and after 57 importance 1N or larger flares have been examined for changes in the magnetic fields (B ) transverse to the line of sight. It was assumed that H chromospheric structures outline B . In 37% of the cases, there was a reconfiguration of segments of filaments or of chromospheric fibrils. Examination of data from 21 non-flare intervals shows such changes in 24% of cases. When changes of any kind, including total disappearance and length changes, are included, the proportions for flare and non-flare intervals increase to 58% and 52%, respectively. It is concluded that flares do not cause enduring magnetic field changes in the chromosphere.  相似文献   

11.
A possibility of developing the analytical theory of perturbed motion for a balloon-satellite influenced by solar radiation pressure force is analysed here on the basis of the limit case modification of the two fixed centers problem whose force-field is a superposition of the Newtonian central field and a homogeneous one. Such an approach enables us in the intermediate orbit already to take into account the effect of a constant force, all coordinates of a satellite being expressed as functions of some monotonically increasing variable by means of inversion of elliptic quadratures. The relations between canonical constants of the intermediate orbit and a quasikeplerian elements coinciding in the absence of solar radiation pressure with keplerian ones are derived. The numerical results and illustrating the perturbations in the radius-vector of the intermediate orbit of a balloon-satellite of the Echo-I type are given.
-, , , . , , . , . , - - -I.
  相似文献   

12.
Quasi-steady high-temperature current sheets are an energy source during the main or hot phase of solar flares. Such sheets are shown to be stabilized with respect to the tearing instability by a small transverse component of magnetic field existing in the sheets.  相似文献   

13.
, — . , , . , , .  相似文献   

14.
, , . , . ( , , ), - qqi . - ; , - . , , .  相似文献   

15.
During 1967–1970, the greatness of 90 large flares (H importance 2) was influenced by the orientation of the large-scale ( 100 000 km) magnetic field structure over the flare site. Although the average X-ray and optical emissions are only slightly larger for flares with their overlying fields directed southward, as opposed to northward, the meter-wave-length prompt flux maxima are, on average, an order of magnitude greater for the flares with southward oriented magnetic fields. There is a comparable, but possibly smaller difference in the 10 cm- fluxes. We therefore conclude that, during this period, the orientation of the overlying magnetic field affects the amount of electromagnetic flare energy radiated promptly in the corona (10 cm- and m-), relative to that radiated in the chromosphere (X-ray and optical). We demonstrate that this statistical effect shows some variability in degree during the period, although the trend is consistent throughout.  相似文献   

16.
Exploratory observations at 20 and 350 have determined detection thresholds for solar flares in these wavelengths. In the 20 range solar atmospheric fluctuations (the temperature field) set the basic limits on flare detectability at 5K; at 350 the extinction in the Earth's atmosphere provides the basic limitation of 30K. These thresholds are low enough for the successful detection of several infrared-emitting components of large flares. Limited observing time and lack of solar activity have prevented observations of large flares up to the present, but the techniques promise to be extremely useful in the future.The upper limits obtained thus far, for subflares, indicate that the thickness of the H flare region does not exceed 10 km. This result confirms the conclusion of Suemoto and Hiei (1959) regarding the small effective thickness of the H-emitting regions in solar flares.  相似文献   

17.
An analysis of the effects of Hall current on hydromagnetic free-convective flow through a porous medium bounded by a vertical plate is theoretically investigated when a strong magnetic field is imposed in a direction which is perpendicular to the free stream and makes an angle to the vertical direction. The influence of Hall currents on the flow is studied for various values of .Nomenclature c p specific heat at constant pressure - e electrical charge - E Eckert number - E electrical field intensity - g acceleration due to gravity - G Grashof number - H 0 applied magnetic field - H magnetic field intensity - (j x , j y , j z ) components of current densityJ - J current density - K permeability of porous medium - M magnetic parameter - m Hall parameter - n e electron number density - P Prandtl number - q velocity vector - (T, T w , T ) temperature - t time - (u, v, w) components of the velocity vectorq - U 0 uniform velocity - v 0 suction velocity - (x, y, z) Cartesian coordinates Greek Symbols angle - coefficient of volume expansion - e cyclotron frequency - frequency - dimensionless temperature - thermal conductivity - coefficient of viscosity - magnetic permeability - kinematic viscosity - mass density of fluid - e charge density - electrical conductivity - e electron collision time  相似文献   

18.
An extensive analysis is made of the theory of flare stars based on the fast electron hypothesis, in the light of the latest observational evidence. It is shown that an adequate agreement of theory with the observations obtains regarding the internal regular features in the flare amplitude data inUBV rays, as well as the changes of the colour characteristics of stars during the flares; in the latter case the analysis is made not only in respect of the UV Cet-type stars, but flare stars as well, forming a part of the Orion association. Problems bearing on the negative flare and the screening effect are dealt with. New properties of the light curves of flares are revealed, based on the above theory.Particular emphasis is laid on the X-ray radiation from flare stars. It is shown that the observed spectrum of X-ray radiation of flare stars differs sharply from that of X-ray radiation both of the stellar corona and solar X-ray flares. At the same time, the observed X-ray spectrum of flares is in complete harmony with the previously calculated theoretical spectrum corresponding to nonthermal bremsstrahlung with the energy of monoenergetic fast electrons 1.5 MeV. The durations of X-ray flares should be essentially shorter than that of the optical flares. The very high momentary intensities of the X-ray brightness with the exceedingly small duration at the curve maximum is predicted. It is shown that the gamma-ray bursts recorded so far have no relation whatever to flare stars.  相似文献   

19.
. . .
Transfer of resonance radiation in infinite medium is considered as a process of random walks of photons. Close relation is shown to exist between the problems of transfer of line radiation and the stable distributions of the probability theory. This relation is used as a basis of a new method for the investigation of the asymptotic properties of the radiation field far from the sources.

,   相似文献   

20.
H. Zirin 《Solar physics》1978,58(1):95-120
I have studied a number of flares for which good X-ray and optical data were available. An average lag of 5.5 s between hard X-ray (HXR) start and H start, and HXR peak and Ha peak was found for 41 flares for which determination was possible. Allowing for time constants the time lag is zero. The peak H lasts until 5–6 keV soft X-ray (SXR) peak. The level of H intensity is determined by the SXR flux.Multiple spikes in HXR appear to correspond to different occurrences in the flare development. Flares with HXR always have a fast H rise. Several flares were observed in the 3835 band; such emission appears when the 5.1–6.6 keV flux exceeds 5 × 104 ph cm-2 s-1 at the Earth. Smaller flares produce no 3835 emission; we conclude that coronal back conduction cannot produce the bright chromospheric network of that wavelength.The nearly simultaneous growth of H emission at distant points means an agent travelling faster than 5 × 103 km s-1 is responsible, presumably electrons.In all cases near the limb an elevated Ha source is seen with the same time duration as HXR flux; it is concluded that this H source is almost always an elevated cloud which is excited by the fast electrons. A rough calculation is given. Another calculation of H emission from compressed coronal material shows it to be inadequate.In several cases homologous flares occur within hours with the same X-ray properties.Radio models fit, more or less, with field strengths on the order of 100G. A number of flares are discussed in detail.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号