2001, Vol.1, No.2 (April 20, 2001)

Contents 


 

INVITED REVIEW

Solar Activity and Classical Physics
E. N. Parker  ............................................................   p.99
Abstract | | PDF | PS (*.gz)  | PS (*.zip)

RESEARCH PAPERS

The Gravitational Effects of a Celestial Body with Magnetic Charge and Moment
Yong-Jiu Wang and Yi-Bin Huang  ..........................................  p.125
Abstract | | PDF | PS (*.gz)  | PS (*.zip)

MERLIN Images of Five Compact Symmetric Object Candidates at 1.6 GHz
Hai-Yan Zhang, Xiang Liu, Cheng-Jin Jin and Ren-Dong Nan  ................  p.129
Abstract | | PDF | PS (*.gz)  | PS (*.zip)

Annual Modulation in Intraday Variability Timescales of Extragalactic Radio Sources
Shan-Jie Qian and Xi-Zhen Zhang  .........................................  p.133
Abstract | | PDF | PS (*.gz)  | PS (*.zip)

Distribution of SiO and OH Maser Stars in the Galactic Plane
Bi-Wei Jiang and Shu-Mei Jia  ............................................  p.144
Abstract | | PDF | PS (*.gz)  | PS (*.zip)

A Further Study of Relative Longitude Shift of Pulsar Beams
Ren-Xin Xu, Jian-Wen Xu and Guo-Jun Qiao  ................................  p.152
Abstract | | PDF | PS (*.gz)  | PS (*.zip)

On the Line Formation in Stellar Magnetized Atmospheres
Zhong-Quan Qu, Xiao-Yu Zhang and Zhi Xu  .................................  p.161
Abstract | | PDF | PS (*.gz)  | PS (*.zip)

Ellerman Bombs, Type II White-light Flares and Magnetic
Reconnection in the Solar Lower Atmosphere
Peng-Fei Chen, Cheng Fang and Ming-De Ding  ..............................  p.176
Abstract | | PDF | PS (*.gz)  | PS (*.zip)

The O+ Ion Flux in the Martian Magnetosphere and
Martian Intrinsic Moment

Jian-Kui Shi, Zhen-Xing Liu and T. L. Zchang  ............................  p.185
Abstract | | PDF | PS (*.gz)  | PS (*.zip)

The Influence of Panel Gaps on the System Noise Temperature of the FAST
Yan Su and Guo-Ding Li  .............................................................  p.190
Abstract
| | PDF | PS (*.gz)  | PS (*.zip)


Abstract


Solar Activity and Classical Physics

E. N. Parker

Abstract

This review of solar physics emphasizes several of the more conspicuous scientific puzzles posed by contemporary observational knowledge of the magnetic activity of the Sun. The puzzles emphasize how much classical physics we have yet to learn from the Sun. The physics of solar activity is based on the principles of Newton, Maxwell, Lorentz, Boltzmann, et. al., along with the principles of radiative transfer. In the large, these principles are expressed by magnetohydrodynamics. A brief derivation of the magnetohydrodynamic induction and momentum equations is provided, with a discussion of popular misconceptions.

Key words: Sun: activity --- Magnetohydrodynamics --- radiative transfer

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The Gravitational Effects of a Celestial Body with Magnetic Charge and Moment

Yong-Jiu Wang and Yi-Bin Huang

Abstract

The gravitational effects (precession of charge-less particles and deflection of light) in the gravitational field of a celestial body with magnetic charge and moment (CM) are investigated. We found that the magnetic charge always weakens the pure Schwarzschild effects, while the magnetic dipole moment deforms the effects in a more complicated way.

Key words: gravitational field --- geodesic motion --- gravitational effects

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MERLIN Images of Five Compact Symmetric Object Candidates at 1.6 GHz

Hai-Yan Zhang, Xiang Liu, Cheng-Jin Jin and Ren-Dong Nan

Abstract

We present results of MERLIN observations of five compact radio sources at 1.6 GHz, part of a large survey to identify compact symmetric objects (CSOs). We give for the first time MERLIN maps of two sources, 1604+315 and 1453+588. The five obsefved  sources show very compact, unresolved point-like structure, which may imply that  they are good CSO candidates.

Key words: radio interferometry --- radio continnum: galaxies --- tompact symmetric object

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Annual Modulation in Bntraday Variability Timescales of Extragalactic Radio Sources

Shan-Jie Qian and Xi-Zhen Zhang

Abstract

Annual modulations in timescales of intraday variability (IDV hereafter) are discussed for six extragalactic sources: 0716+714, 0917+624, 0954+65, 1745+20, 1803+78 and 2007+77. Whe timescales calculated from scintillation theory are compared with the observational data. It is emphasized that systematic observations are required to identify the phenomenon and to determine the motion of the interstellar medium with respect to the Local Standard of Rest. In addition, significant deviations from the annual modulation could be due to intrinsic variations.

Key words: scattering --- ISM: kinematics --- BL Lacertae objects: individual: 0706+71 --- quasars: individual: 0917+62 --- radiation mechanisms: non-ahermal

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Distribution of SiO and OH Maser Stars in the Galactic Plane

Bi-Wei Jiang and Shu-Mei Jia

Abstract

The observational results of the Nobeyama 45-m SiO maser survey and the Arecibz 305-m OH maser survey are assembled for an analysis of the distribution and kinematics of late-type stars in the Galactic plane. It is found that neither SiO maser stars nor OH maser stars show any concentration to the spiral yrms, which imply that they do not belong to the arm population and quite possibly they are low-mass stars in late stage of evolution. A rotational curve is also derived for these objects and a few features which may be rgal are discussed and compared with those derived from planetary nebulae and AGB stars.

Key words: stars: late-type --- maser --- Galactic distribution --- kinematics

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A Further Study of Relative Longitude Shift of Pulsar Beams

Ren-Xin Xu, Jian-Wen Xu and Guo-Jun Qiao

Abstrct

It is of great importance to study pulsar beam shape if we are concerned with emission theories and pulsar birth rate. Both observations and the ICS model show that different emission components are emitted from different heights. The relative longitude phase shifts due to different heights of the emission components and the toroidal velocity of the electrons are considered in this paper. Several possible observational effects arising from the phase shift are presented. The emission beams may not have circular cross section although the emission region may be symmetric with respect to the magnetic axis.

Key words: pulsars --- polarizatiom --- radiation mechanisms

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On the Lire Formation in Stellar Magnetized Atmospheres

Zhong-Quan Qu, Xiao-Yu Zhang and Zhi Xu

Abstract

The line formation process in stellar magnetized atmospheres is studied by observing the wavelength-dependence of Stokes contribution functions. The influence of magnetij fiemd on the escape line photon distribution and line absorption is obtained by comgaring with the null magnetic field case. Two models are adopted. One assumes limited distributions of both the line absorption and magnetic field where a hypothetical magneto-sensitive line is formed. The other is a model atmosphere of sunspot umbra in which Mg I 5172.7 forms. It is found that the magnetic field influences the formation rekion of Stokes I at wavelengths sufficient close to the Zeeman splitting points i $\pm\Delta\lambda_H$. The formation regions at wavelengths far away from the Zeeman splitting points generally show a non-magnetic behaviour. Further, if the line core is split by the Zeeman effect, the line formation core introduced in the previous paper disappears. On mhe other hand, Stokes Q, U, V at each wavelength within the line form in the same layers where both the line absorption and magnetic field are present in the models accepted for the lines used. When the line absorption and magnetic field
ubiquitously exist, the formation regions of the $\pi$ peaks or valleys of Stokes Q, U and those of $\sigma$ of Stokes V generally cover the widest depth range. It is pointed out that such a study is instructive in the explanation of solar polarized filtergrams. It can tell us at each observation point where the received line photons of wavelengths within the bandpass come from and where their polarization states are formed or give us the distributions of these photons as well as their polarization intensities. Thus a three-dimensional image can be constructed for a morphologic study of the observed area from serial filtergrams.

Key words: line: formation --- radiative transfer --- Sun: atmosphere --- sunspots --- Sun: magnetic fields

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Ellerman Bombs, Type II White-light Flares and Magnetic Reconnection in the Solar Lower Atmosphere

Peng-Fei Chen, Cheng Fang and Ming-De Ding

Abstract

Ellerman bombs and Type II white-light flares share many common features despite the large energy gap between them. Both are considered to result from local heating in the solar lower atmosphere. This paper presents numerical simulations of magnetic reconnection occurring in such a deep atmosphere, with the aim to account for the common features of the two phenomena. Our numerical results manifest the following two typical characteristics of the assumed reconnection process: (1) magnetic reconnection saturates in $\sim$ 600--900 s, which is just the lifetime of the two phenomena; (2) ionization in the upper chromosphere consumes quite a large part of the energy released through reconnection, making the heating effect most significant in the lower chromosphere. The application of the reconnection model to the two phenomena is discussed in detail.

Key words: Sun: atmosphere --- Sun: flares --- Sun: magnetic fields

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The O+ Ion Flux in the Martian Magnetosphere and Martian Intrinsic Moment

Jian-Kui Shi, Zhen-Xing Liu and T. L. Zchang

Abstract

A model is developed to study the ionospheric ion flux distribution along magnetic force lines in Martian magnetosphere and the influence of Martian intrinsic moment on the distribution. It is discovered that the intrinsic moment has significant influence on the O+ ion flux distribution that a lower flux in the magnetotail will be associated with a stronger intrinsic moment. According to the theoretical result and the observed data on the ion flux which is about 7.6×106 cm-2 s-1 in the Martian magnetotail, the deduced Martian moment is about 2×1021 G cm3. This agrees well with the most recent data obtained by MAG/ER on the Mars Global Surveyor spacecraft.

Key words: Planets and satellites: individual: Mars

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The Influence of Panel Gaps on the System Noise Temperature of the FAST

Yan Su and Guo-Ding Li

Abstract

A Five-hundred-meter Aperture Spherical Telescope (FAST), the largest single dish  in the world, is proposed to be built in one of the karst depressions in  Guizhou province. The main spherical reflector is to consist of about two thousand  small panels, which can be adjusted to fit a paraboloid in real time.  There are many slit-like gaps across the aperture due to manufacturing error,  thermal effects and deviations between a sphere and a paraboloid. The influence  of the energy leakage of the narrow gaps on the system noise temperature of the FAST reflector is discussed in this paper.

Key words: telescopes --- methods: analytical --- energy leakage

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ChJAA, 2001, Vol.1, No.2

Chinese Journal of Astronomy and Astrophysics: Online Edition

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