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1.
Л. Г. Лукьялов 《Celestial Mechanics and Dynamical Astronomy》1976,13(4):455-464
, . . . .
Some asymptotic solutions in the restricted problem of three bodies by L. G. Lukjanov.
Some particular solutions of the plane restricted problem of three bodies in the form of Liapunov's series are obtained. These solutions asymptotically approach the Lagrange solutions. Convergence is proved.相似文献
2.
Using the flux-transport equation in the absence of sources, we study the relation between a highly peaked polar magnetic field and the poleward meridional flow that concentrates it. If the maximum flow speed
m greatly exceeds the effective diffusion speed /R, then the field has a quasi-equilibrium configuration in which the poleward convection of flux via meridional flow approximately balances the equatorward spreading via supergranular diffusion. In this case, the flow speed () and the magnetic field B() are related by the steady-state approximation () (/R)B()/B() over a wide range of colatitudes from the poles to midlatitudes. In particular, a general flow profile of the form sin
p
cos
q
which peaks near the equator (q p) will correspond to a cos
n
magnetic field at high latitudes only if p = 1 and
m = n /R. Recent measurements of n 8 and 600 km2 s–1 would then give
m 7 m s–1. 相似文献
3.
J. F. Valdés-Galicia G. Wibberenz J. J. Quenby X. Moussas G. Green F. M. Neubauer 《Solar physics》1988,117(1):135-156
In the quasi-linear theory of pitch angle scattering the power spectrum of magnetic field fluctuations is related to the shape of the pitch angle diffusion coefficient D(), the absolute value of the mean free path , and the rigidity dependence of the mean free path (R). We discuss these relations in detail during the solar particle event of 11 April, 1978 which was observed on HELIOS-2 at a distance of 0.49 AU from the Sun. Magnetic field measurements obtained during the time of the event are used as a basis for the layer model in which the method of particle trajectories in an actually measured field is used to simulate pitch angle diffusion. The values of D() and based on the trajectory simulation for 100 MeV protons (field approach) are compared with results obtained from solar proton data (particle approach) and with predictions from quasi-linear theory based on the additional assumption of the slab model for magnetic field fluctuations (QLT approach). The time of the event is characterized by a high level of field fluctuations, the observed mean free path of about 0.03 AU for 100 MeV protons is smaller than the average value near 1 AU. Results from the field and particle approaches agree surprisingly well. The remaining difference in the mean free path of about a factor of 2 could be due to tangential discontinuities which are measured by the magnetometer, but not seen by the real particles traveling along the average field. The results from the field and QLT approaches based on the same set of magnetic field measurements differ by about a factor of 4. One of the reasons for this discrepancy is that the conditions for resonance scattering are only marginally valid. In addition, the wave vectors representing Alfvén-type fluctuations may not be totally field aligned. This deviation from the slab model would cause an increase of the theoretically predicted mean free path and lead to better agreement with the other two approaches. 相似文献
4.
, , , , . , , . , , - - ( , ..). - . 相似文献
5.
R. B. Shatsova 《Astrophysics and Space Science》1993,201(1):91-105
Many HVC - high velocityHi clouds - are added to the known combination of diffuse soft X-rays and radioloops. Among these HVC there are previously examined complexes A, C, Magellanic Stream, etc. Their common composition has a clear geometry and kinematics.Two powerful long HVC filaments form the bridges between Loop I and double Loop II + III. The Bridges join the polarX
max regions in C band. The bridges ends at Loop I side are bounded by the systems of shorter filaments withX
max spots in M1 and larger energy bands. There are no HVC in the spots themselves. The opposite ends of bridges reach Loops II and III centres. The two structures have the features of rotational symmetry.The isolines X-ray count rates pass along HVC chains with the same
r
-velocities. The frequent alternation of different
r
on the same filament is better explained by the turbulent gas motion than by the differences of HVC distance.All of the above-mentioned, as well as the
r
signs of dependence on the galactical longitude, are the result of HVC interaction with X-rays. The whole composition from HVC-loops-X-rays is a component of the local system (Gould Belt). 相似文献
6.
The gravity potential of an arbitrary bodyT is expanded in a series of spherical harmonics and rigorous evaluations of the general termV
n
of the expansion are obtained. It is proved thatV
n
decreases on the sphere envelopingT according to the power law if the body structure is smooth. For a body with analytic structure,V
n
decreases in geometric progression. The exactness of these evaluations is proved for bodies having irregular and analytic structures. For the terrestrial planetsV
n
=O (n
–5/2).
I I V n IV n I . . IV n I . I. IV n =O(n –5/2 )相似文献
7.
, . : , . , . . ( ) . . . HZ Her=Her X1, . . , . , ., hv 15–30 . , . Sco X1 . 相似文献
8.
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.
Г. А. Гурзадян 《Astrophysics and Space Science》1979,64(1):3-23
2800 Mgii (. 1). (N
+/N
11000) , , (N
+/N
110). , . —, , . — . : ; 0.002 1 , 0.1 ; () 100 –3; ; ; , 10
; 10–4
1
. 2800 Mgii . 相似文献
11.
. - . . , . - . - , , , -. ., , .
English translation will appear in the next issue ofAstrophys. Space Sci.
Receipt delayed by postal strike in Great Britain 相似文献
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
12.
From theH
filtergram observations obtained at Ganyu station, identification and statistic works made for Ellerman bombs, it is found that they often occur in the superpenumbra area of a mature sunspot. We suggest a plasmoid model to account for the basic properties of a typical bomb: lifetime 11 min, diameter 5 × 107 cm, accompanying jet velocity 40 km/s, total energy 1027 erg,Te 104 K. First, a numerical simulation is made to prove that plasmoids can be lifted from the solar convective zone by magnetic buoyancy. Between the plasmoid and its surroundings a strong current sheet builds up in which a peculiar MHD (with plasma ponderamotive force) - resistive instability takes place. After the magnetic reconnection has begun, a local explosive instability ensues whose growth rate is so high that it allows the exhaustion of the high temperature particles from the sheet in a short period. In this way, the temperature of a bomb may be kept unchanged or only rise slightly. 相似文献
13.
H observations, using the Multichannel Subtractive Double Pass (MSDP) spectrograph operating on the Meudon Solar Tower, have been made of an active region filament which undergoes a disparition brusque. The period of observation was from 10 45 to 13 30 UT on 22 June, 1981. Velocity and intensity fluctuations in H were measured. The proper motions of ejecta were followed allowing their trajectories and vector velocities to be determined. To model the dynamics of ejecta several models using thermal or magnetic driving forces are compared. The most promising model explains the motion as the consequence of magnetic stresses acting on an isolated magnetized plasmoïd in a diverging flux tube. 相似文献
14.
As a possible mechanism for particle acceleration in the impulsive phase of solar flares, a new particle acceleration mechanism in shock waves is proposed; a collisionless fast magnetosonic shock wave can promptly accelerate protons and electrons to relativistic energies, which was found by theory and relativistic particle simulation. The simultaneous acceleration of protons and electrons takes place in a rather strong magnetic field such that
ce
pe
. For a weak magnetic field (
ce
pe
), strong acceleration occurs to protons only. Resonant protons gain relativistic energies within the order of the ion cyclotron period (much less than 1 s for solar plasma parameters). The electron acceleration time is shorter than the ion-cyclotron period. 相似文献
15.
A model of interplanetary and coronal magnetic fields 总被引：5，自引：0，他引：5
A model of the large-scale magnetic field structure above the photosphere uses a Green's function solution to Maxwell's equations. Sources for the magnetic field are related to the observed photospheric field and to the field computed at a source surface about 0.6 R
above the photosphere. The large-scale interplanetary magnetic field sector pattern is related to the field pattern at this source surface. The model generates magnetic field patterns on the source surface that compare well with interplanetary observations. Comparisons are shown with observations of the interplanetary magnetic field obtained by the IMP-3 satellite. 相似文献
16.
The problem of stability of an unbounded anisotropic plasma characterized by different temperatures along and transverse to the magnetic field is investigated for an arbitrary direction of propagation. Chewet al (1956) equations modified to incorporate self-gravitation, finite ion Larmor radius (FLR) and Hall current are used. Uniform rotation (of an order of interest in astrophysics) is also considered. Extensive numerical treatment of the dispersion relation leads to several interesting results.Inclusion of FLR, or Hall current or both together introduces pulsational instability for prepagation parallel to the magnetic field. The aperiodic growth rate of the mirror instability is only slightly altered due to FLR or Hall current effects. In the absence of rotation, self-gravitation, FLR and Hall current, the growth rate decreases for the mirror region as the direction of propagation approaches the field direction, while the fire hose instability persists for arbitrary propagation, even in the limiting case (the mirror limit) where the propagation is nearly transverse to the magnetic field. Uniform rotation altogether stabilizes the fire hose instability for a sufficiently strong pressure (or temperature) anisotropy. Pulsational instability is introduced when both ratation and self-gravitation effects are present. Either FLR or Hall current depresses the growth rate of the fire hose instability and introduces pulsational instability for the general case of arbitrary propagation. When FLR and Hall current effects are present simultaneously, the interaction terms due to these effects may be strongly destabilizing in nature for arbitrary propagation. 相似文献
17.
Simple self-consistent models for non-neutral current sheets are considered. Characteristics of high-temperature turbulent current sheets (HTCS) with a small transverse component of magnetic field are determined for conditions in the solar corona. The energy output of such an HTCS is much larger than that of a neutral sheet. This makes it possible to consider the HTCS as an energy source not only in long-lived X-ray loops but also in flaring loops during the not or main phase of a flare. In this case, the magnetic reconnection velocity agrees with the observed velocity of the loop rise. Thus, these phenomena can be interpreted as a result of magnetic reconnection, for example, between new flux emerging from under the photosphere and an old magnetic field.The role of a longitudinal magnetic field in a current sheet is less important for HTCS. As a result of the compression of a longitudinal field, there appears an electric current circulating around the sheet. This current may induce strong Joule heating, if the compression is large. This additional heating is realized because of the annihilation of the main component, not the longitudinal component of magnetic field. The effect is small for HTCS, but may be significant for preflare current sheets. 相似文献
18.
, () , , ( =2) , . (, , ). ( =0,5) . 相似文献
19.
20.
The effect of small perturbations and in the coriolis and the centrifugal forces respectively on the stability of the triangular points in the restricted problem of three bodies with variable mass has been studied. It is found that the range of stability of triangular points increases or decreases depending upon whether the perturbation point (, ) lies in one or the other of the two parts in which the (, ) plane is divided by the line J8–J9=0 where J8 and J9 depend upon , the constant due to the variation in mass governed by Jeans' law. 相似文献