1991 Vol. 11, No. 4

Display Method:
CENTER-TO-LIMB VARIATION OF SPECTRAL LINES AND QUIET SUN ATMOSPHERIC MODEL
Ding Ming-de, Fang Cheng
1991, 11(4): 241-250. doi: 10.11728/cjss1991.04.241
Abstract(1685) PDF 668KB(618)
Abstract:
In this paper, the spectral lines of hydrogen and ionized calcium, as well as their center-to-limb variations, observed at Kitt Peak National Solar Observatory, are used to diagnose the VAL-C', quiet Sun atmospheric model. The PANDORAcomputer program is used to perform the detailed non-LTEmodel calculations, especially for hydrogen and calcium. The main discrepancies between the computed spectral lines and the observed data are: (1) The residual intensity in Hβ andλ8498 line centers is evidently higher, while that in CaII Hand Klines are relatively lower than the observed values; (2) The center-to-limb enhancement coefficient of the residual intensities of Hβ, and all the CaIIlines (resonance and infrared lines) near Δλ = 0.5Å is a little larger than indicated by the observation. However, all other spectral features observed can be reproduced fairly well. Finally, the possible causes which can make the computed values deviate from the observed ones is discussed, and a comment on revising the VAL-C' model is given.
CHARGE STATES OF SOLAR ENERGETIC PARTICLES AND CORRELATIONS BETWEEN PARTICLE INTENSITIES
Huang Yong-nian
1991, 11(4): 251-257. doi: 10.11728/cjss1991.04.251
Abstract(1686) PDF 464KB(811)
Abstract:
A possible ionic charge state distributions of He, C, N, O, Ne, Mg, Si, Sand Fe in solar energetic particle events is presented in this paper. The number of different ionic orders in the distributions of elements increases with the elemental mass except for He. The correlations between the mean particle intensities for the elements as a function of mean intensities of Cin the energy range 2-3 MeV per nucleon can be explainel in terms of the increase of ionic-order number with mass for the elements. The ionic charge states cannot be explained in a model in which the coronal temperature determines a charge equilibrium. It is concluded that ionic charges of solar energtic particles can be produced in a solar flaring region rather than in an interplanetary shock region.
THE FEATURES OF THE GROUND LEVEL ENHANCEMENT EVENT OF COSMIC RAY ON 29 SEPTEMBER 1989
Ye Zong-hai
1991, 11(4): 258-266. doi: 10.11728/cjss1991.04.258
Abstract(1838) PDF 582KB(888)
Abstract:
The ground level enhancement (GLE) from the solar proton flare of 29, Sept., 1989 is recorded by the world wide network of the neutron monitors and μ-meson telescopes. This GLEis the greatest event since the event on 23 Feb. 1956. The features of the world wide GLEincluding the intensity time profiles, the spectrum, the anisotropy and the geographical distribution etc. are studied in this paper. And the influences of the GLEon the earth's environment are described briefly in this paper.
SIMULATION OF COMPRESSIBLE VORTEX-INDUCED RECO-NNECTION AT THE DAYSIDE MAGNETOPAUSE REGION:THE FORMATION AND STRUCTURE OF FTES
Zhu Zhong-wei, Liu Zhen-xing, Pu Zu-yin
1991, 11(4): 267-277. doi: 10.11728/cjss1991.04.267
Abstract(1765) PDF 683KB(864)
Abstract:
By using a two-dimensional compressible MHD model, the local reconnection processes at the dayside magnetopause region are simulated based on the theory of vortex-induced reconnection. This process is: first, a fluid vortex is formed, which in turn, induce the reconnection so that a magnetic vortex is formed, and finally there will be a magnetic fluid vortex (MFvortex), of which the three-dimensional structure is a MFvortex tube. The MF vortex tube connectes the magnetosheath and the magnetosphere region. The compressible model is compared with the incompressible model, it is found that the growth of vortices under incompressible condition is faster than that for compressible condition, but the forms of vortices are analogous. It is thought that vortes-induced reconnection is an important machanism of flux transfer events (FTEs) formation, and the FTE tube is a MF vortex tube. The signatures of the magnetic field, velocity, density, temperature, and pressure of the FTEare simulated. The simulation results are consistent with observational examples of FTES.
A COUPLING RELATION BETWEEN OZONE DENSITY OSCILLATIONS AND TEMPERATURE FLUCTUATIONS NI THE LOWER THERMOSPHERE
Xiao Fu-liang, Chen Yao-wu, R. J. Huang
1991, 11(4): 278-285. doi: 10.11728/cjss1991.04.278
Abstract(1821) PDF 506KB(866)
Abstract:
In the course of acoustic-gravity wave (AGW) propagation, a coupling relation between the ozone density oscillations (ODO) and temperature fluctuations (TF) in the lower ther-mosphere is presented. The physical essences of the relation mentioned are analyzed and a criterion is suggested that positive or negative coupling relation is mainly dependent upon the scales of the dynamical perturbations. On a small and medium AGW scale, the coupling relation between ODOand TFis always positive, and the amplitude of coupling relation can be or exceed 7; on the large AGW scale or planetary-wave scale, the coupling relation becomes negative. This finding may explain the important facts in observations that the ozone density and temperature in the upper mesosphere and lower thermosphere appear to be in fast variations and the zonal mean values of ozone density over a long time are often in opposite phase relative to the temperature fluctuations. Afurther comparison indicates, there is no obvious difference between the influences on the criterion by using linear or nonlinear AGW theories.
THE GREEN CORONAL LINE ABOVE ACTIVE REGION AT SOLAR LIMB ON 5 AUG. OF 1989
Du Jin-sheng, N. F. Tyagun, G. M. Khmyrov
1991, 11(4): 286-290. doi: 10.11728/cjss1991.04.286
Abstract(2011) PDF 525KB(583)
Abstract:
The green coronal line above sunspot group of No.5629 of 5 Agu. of 1989 with excited continuum and bright knots is observed. According to the intensities of the continuum, the following parameters are estimated: the electron densities are 3×109-1011/cm, half width is up to 1.2Å, temperature is 4-5×106 K without considering turbulent velocity, and the sizes of strong radiation regions along the direction of line of sight are 0.5×109cm.
THE QUANTITATIVE RESEARCH ON THE VELOCITY FIELD OF A POST-FLARE LOOP PROMINENCE SYSTEM
Gu Xiao-ma, Lin Jun, Li Qiu-sha
1991, 11(4): 291-300. doi: 10.11728/cjss1991.04.291
Abstract(1477) PDF 624KB(937)
Abstract:
The downward motion of the matter within the post-flare loop system of 1984 February 18 is studied under the joint action of solar gravity and the 'both gradients of dipole magnetic field pressure and atmospheric pressure. The two-dimensional line-of-sight velocity field is calculated by means of a numerical method under the assumption that the temperature keeps unchanged within loop system and the loops are quasi-closed. In the system, some parameters as well as their distribution are derived from the curve fit of both velocity fields between theory and observation. The calculations indicate that the effects of density and magnetic field intensity within the loop system on the downward motion of matter is comparatively large while the effect of the temperature is much small.
ERROR ANALYSIS FOR THE REMOVAL OF THE INTERFERENCE FRINGES FROM A SOLAR IMAGE OBTAINED WITH A CCD SYSTEM BY MEANS OF THE SUBTRACTION
Yang Xiao-rung, Li Zhi
1991, 11(4): 301-307. doi: 10.11728/cjss1991.04.301
Abstract:
This paper briefly reports the causes of the pdoduction of interference fringes of a CCD system. Amethod for removing the interference fringes, by means of the subtraction, from the solar Ha image obtained with the CCD system is also described. Amethod for estimating the error is proposed through tests and studies and the calculated results are analysed and discussed.
THE REFERENCE FRAMES IN THE DATA REDUCTION OFHIPPARCOS SATELLITE
Ling Zhao-fen
1991, 11(4): 308-316. doi: 10.11728/cjss1991.04.308
Abstract(1747) PDF 530KB(1042)
Abstract:
The heliotropic, great-circle and Hipparcos telescope reference frames are explicitly defined in the light of the scanning law of Hipparcos satellite. The differences between the reference frames adopted by the two data reduction consortia, FAST and NDAC, are presented. The abscissas and ordinates of 50 stars in the FAST and NDAC great-circle reference frame are simulated and the reason for using two data reduction consortia in ESAare discussed.