共查询到20条相似文献，搜索用时 468 毫秒
1.
O. A. Golubchina 《Solar physics》1995,160(1):207-212
The recent modernization of the RATAN-600 radio telescope at the Special Astrophysical Observatory has provided an opportunity to develop new procedures, called relay and zoned relay, for utilizing the new cone-surface secondary reflector. The geometric area, the horizontal beamwidth spatial resolution, and the permissible radiometer bandwidth are discussed. We are also able to estimate the changes in the sensitivities of the radio telescope-radiometer systems. The new procedures, called relay and zoned relay, allow us to obtain two-dimensional images of radio objects and to track the development of rapidly varying sources in any azimuth.Presented at the CESRA-Workshop on Coronal Magnetic Energy Release at Caputh near Potsdam in May 1994. 相似文献
2.
Several of the exotic supernova remnants are re-interpreted as pulsar-illuminated former windzones. The class of supernova remnants thus splits into (i) (the usual) shell remnants and (ii) pulsar nebulae in which a (fairly young) pulsar blows its relativistic wind into its low-density environs. 相似文献
3.
V. S. Geroyannis 《Astrophysics and Space Science》1985,117(2):245-260
In this paper, a nontrivial velocity tensor is suitably defined to represent in the common frame the so-called classes of dynamical and kinematical near homoaxial rotations of a deformable finite material continuum. These classes have simple and interesting physical interpretation, especially for treating of nonuniform rotation and its applications to astrophysics. Some important subclasses and derived classes (in the sense of related superclasses) are also discussed.Two coordinate systems are further introduced, one of which rotates uniformly while the other rotates nonuniformly, the latter defined by means of a generalized orthogonal coordinate transformation. Suitable conditions are then given, asserting that the above systems are preferred in the sense of preserving the motion of the continuum in its inertial class.Finally, the required concepts of homotropy and distributivity are defined and the method, by which the established mathematical framework will be subsequently used in applications, is discussed. 相似文献
4.
Robert M. Wilson 《Solar physics》1986,106(1):29-33
Mt. Wilson numbers of spots data (as defined in Howard et al., 1984) appear to be distributed according to even-odd cycle numbering. Linear fits of annual numbers of spots versus annual sunspot number for even- and odd-numbered cycles have slopes which are statistically different at the 5% level of significance. The existence of an even-odd split in Mt. Wilson numbers of spots data may be due either to a real difference in even- and odd-numbered cycles on the Sun or to a difference in weather at Mt. Wilson (perhaps, related to the 22-yr rhythm of drought in the western United States) during even- and odd-numbered cycles, or both. For cycle 22, an even-numbered cycle, the peak numbers of spots is estimated to be near 2600. 相似文献
5.
It is shown that Mie theory predictions of extinction for pure water-ice with the optical constant measured at 100 K do not fit in detail the observed ice absorption feature in infrared objects, although we attempt to explain the observations by considering size distribution and shape of the grains.In addition, based on a similarity between the ice band and the absorption band found in carbon stars, we feel it is questionable whether or not the ice band can really be attributed to the interstellar water-ice. 相似文献
6.
We demonstrate that the problems encountered with the binning analysis essentially lie in the significance test which is used. We review and analyse most of the existing significance tests and show that the use of those based on randomization processes considerably improves the situation. For the one-dimensional binning analysis, we apply the 2 within 4 randomization test, whereas for the two- and the three-dimensional binning analyses we introduce two innovations: the 4 within 16 randomization test and the 8 within 64 randomization test, respectively. 相似文献
7.
We implement a complex-plane strategy and a multiple partition technique to the computation of polytropic models distorted by very strong and very rapid differential rotation. We also verify with our numerical results a heuristic relation between stability and virial theorem. 相似文献
8.
A. M. Uralov 《Solar physics》1996,168(2):311-329
An attempt is made to impart a constructive character to the concept of the solar flaremagnetospheric substorm analogy. An idealized scheme for a two-ribbon solar flare in the originally closed magnetosphere of the active region is discussed. The basis is formed by a terrestrial substorm scenario with two active phases (Mishin et al., 1992). While a quadrupole magnetic configuration turns out to be a solar analog of the Earth's magnetosphere. A physical mechanism that sustains the preflare storage phase, is provided by an instability like a stretching instability of the closed geomagnetotail. The storage process is attributed to the emergence into the corona of closed magnetic flux lines in adjacent (to the location of the would-be flare) regions. The flare flash-phase is determined by the change-over of the stretching instability to a disruption instability of a nonstationary (not neutral) current sheet inside the storage zone. The final recovery phase corresponds to the wellknown Pneuman-Kopp model. 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.
The formation of the bump and the black-body cutoff in the cosmic-ray (CR) spectrum arising from the -meson photoproduction reaction in collisions of UHE CR protons with the microwave background radiation (MBR) is studied. A kinetic equation which describes CR proton propagation in the MBR with account of the catastrophic nature of the -meson photoproduction process is derived. The equilibrium CR proton spectrum obtained from the solution of the stationary kinetic equation is in general agreement with the spectrum obtained under assumption of the continuous energy loss approximation. However, the spectra from point sources noticeably differ from those obtained in the continuous loss approximation. Both, the equilibrium and the point source spectra are modified when taking into account the possible deviation of the MBR spectrum from the Planckian one in the Wien region. Thus, for the recently measured MBR spectrum, which reveals an essential excess in the submillimeter region, the black-body cutoff and the preceding bump shift towards lower energies.Deceased, August 13, 1989. 相似文献
11.
A. Hruška 《Astrophysics and Space Science》1977,50(1):153-161
One component of a three-fluid adiabatic plasma is under certain conditions contained in a restricted region of space by a large-scale electrostatic field generated within the plasma. The containment is discussed here for plasma consisting of ions and two populations of electrons characterized by different pitch angle distribution functions.The bouncing motion of electrons along open fieldlines between a magnetic mirror and an electrostatic mirror produces a velocity distribution function similar to that generated by bouncing particles on closed fieldlines. 相似文献
12.
V. A. Ruban 《Astrophysics and Space Science》1977,46(2):L23-L28
It is shown that, for the scalar-tensor cosmology (STC) by Jordan-Brans-Dicke (JBD), in general anisotropic solution the oscillatory mixmaster regime near the singularity will be destroyed by the scalar source-free field and replaced by monotonousV
3-collapse into the point or into the line and plane (only in caseG0) even in the presence of the primordial source-free electromagnetic (EM) field. 相似文献
13.
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
14.
As a birefringent filter is tuned from the center of H to the continuum the H bright mottles appear to break up into a network of grains. The name filigree is suggested for this bright network. Its size, shape, contrast and time evolution is described as well as its relation to the abnormal granulation, magnetic field and spicules.On leave from The University of Hawaii. 相似文献
15.
We numerically study the bifurcations of two nonlinear maps, with the same linear part, which depend on a parameter namely the Hénon quadratic map and the so called beam-beam map. Many families of periodic orbits which bifurcate from the central family, are studied. Each family undergoes a sequence of period doubling bifurcations in the quadratic map, But the behavior of the beam-beam map is completely different. Inverse bifurcations occur in both maps. But some families of the same type which bifurcate inversely in the quadratic map do not bifurcate inversely in the beam-beam map, even though both maps have common linear part. 相似文献
16.
K. S. Bhamra A. M. Finkelstein V. Ja. Kreinovich L. E. Gurevich 《Astrophysics and Space Science》1978,57(2):371-380
The complete analysis of possible types of non-relativistic and ultra-relativistic motions in the field of the naked singularity of the STGT is given. The problem of the infall of a monochromatic radiation emitter on the naked singularity is studied. In spite of the absence of a freezing effect in the STGT, the naked singularity is not observable, for the brightness of the falling emitter decreases much faster than in the GTR. Atrr
g
, the trajectory of particles and light are quite similar to that of the GTR, and due to this fact the naked singularity is observationally indistinguishable from a black hole. 相似文献
17.
G. Contopoulos 《Celestial Mechanics and Dynamical Astronomy》1986,38(1):1-22
We study the bifurcations of families of double and quadruple period orbits in a simple Hamiltonian system of three degrees of freedom. The bifurcations are either simple or double, depending on whether a stability curve crosses or is tangent to the axis b=–2. We have also generation of a new family whenever a given family has a maximum or minimum or .The double period families bifurcate from simple families of periodic orbits. We construct existence diagrams to show where any given family exists in the control space (, ) and where it is stable (S), simply unstable (U), doubly unstable (DU), or complex unstable (), We construct also stability diagrams that give the stability parameters b1 and b2 as functions of (for constant ), or of (for constant ).The quadruple period orbits are generated either from double period orbits, or directly from simple period orbits (at double bifurcations). We derive several rules about the various types of bifurcations. The most important phenomenon is the collision of bifurcations. At any such collision of bifurcations the interconnections between the various families change and the general character of the dynamical system changes. 相似文献
18.
The RISE/PSPT (Radiative Inputs from the Sun to the Earth/Precision Solar Photometric Telescopes) experiment will attain high differential photometric precision in full-disk solar images with 1 arc sec pixels. To achieve this spatial resolution it will be necessary to use frame selection techniques to minimize the effects of atmospheric seeing. We report here on experiments to use a simple scintillation monitor as a trigger or veto for imaging observations.Operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under cooperative agreement with the National Science Foundation. 相似文献
19.
Qualitative considerations of mass and particle loading in plasma-neutral gas interaction are made by the help of a one-dimensional steady model. In the case of particle loading the plasma flow behind a strong shock is accelerated as in the case of mass loading regarded by Biermannet al. (1967) whereas behind a weak shock the flow is decelerated. As an example, one-dimensional time-dependent flows with ionization of the neutral gas by Alfvén's critical velocity effect are calculated. Because of the acceleration of the subsonic flow by loading processes, the existence of a tangential discontinuity in the flow around comets seems questionable. 相似文献
20.
I. Lerche 《Astrophysics and Space Science》1978,57(1):233-239
The behavior of phase speed for the slow and fast magnetosonic waves is well documented in the literature. Not so well documented is the behavior of the ray direction and its relation to the phase direction — indeed we have not found the ray behavior recorded in most of the standard plasma physics texts. We rectify this situation and point out some of the curiosities associated with the direction of the slow ray relative to the direction of the slow phase wave. These calculations have been performed as a necessary basis for discussion of phase and ray evolution of magnetosonic waves in differentially shearing plasmas, which subject is the topic of a later paper. 相似文献