1999 Vol. 19, No. 3

Display Method:
ELECTROMAGNETIC INSTABILITY EXCITED BY RELATIVISTIC BEAM AND RING-BEAM IONS
WANG Xueyi, XU Yonghong, CAO Jinbin, LIU Siqing
1999, 19(3): 193-199. doi: 10.11728/cjss1999.03.193
Abstract(1924) PDF 439KB(1023)
Abstract:
The characteristics of right-circular resonance mode and non-resonance mode excited by cold ion streams are studied in relativistic case. It shows that the growth rate of right circular resonant mode is not sensitive to the initial parameters of ion streams while the growth rate of non-resonant mode is strongly dependent on it.
MODELING STUDY OF THE IONOSPHERIC EFFECTS DURING A SOLAR ECLIPSE OF OCTOBER 24, 1995
LIU Libo, WAN Weixing, TU Jiannan, BAO Zongti
1999, 19(3): 200-205. doi: 10.11728/cjss1999.03.200
Abstract(2439) PDF 332KB(1117)
Abstract:
This paper presents the simulated results of the ionospheric responses to a solar eclipse occurred on October 24, 1995 using a 2D low latitude ionospheric theoretical model. The variations of ion photoionization productions, E×B vertical drifts and electron temperatures induced by the eclipse are considered in the modeling calculations. Results show that during the eclipse, optical eclipse effects are quite clear at the low altitudes, while the responses are smaller, more delayed and longer lasting at the high altitudes. The effects of the depression of electron temperatures induced by the eclipse on the low latitude Flayer are smaller comparing with those caused by variations of EUV fluxes and vertical drifts, which are important for the ionospheric effects of this eclipse.
THE NONLINEAR PROPAGATION OF GRAVITY WAVE PACKETS IN DISSIPTIVE ATMOSPHERE
ZHANG Shaodong, YI Fan, WANG Jingfang
1999, 19(3): 206-212. doi: 10.11728/cjss1999.03.206
Abstract(2162) PDF 430KB(1046)
Abstract:
For elucidating the effect of dissipation on the nonlinear propagation of gravitywave-packet, a numerical simulation of nonlinear propagation of a Gaussian gravitywave-packet in a dissipative atmosphere is carried out and compared with that in a nondissipative atmosphere. The numerical analysis shows that for an initially given upgoing gravity-wave-packet, although there exists the joint action of nonlinear interaction and dissipation during the propagation, the whole wave packet and the wave-associated energy keep moving upward. Wave-associated perturbation velocity increases with the increasing height, but the increased perturbation velocity is much less than that in the nondissipative case, on the other hand, the ambient shows an obvious enhancement. The wave-associated energy decreases monotonously with time. The propagation path and velocity of wave-associated energy coincides well with those in the nondissipative case. These indicate that when a gravity-wave-packet propagates in a dissipative atmosphere, there is no obvious effects of dissipation on the energy propagation of gravity wave. The dissipation can only restrict the increment of the disturbance velocity and transmit the wave energy to the ambient.
THE INFLUENCE OF GRAVITY WAVES ON PHOTOCHEMICAL HEATING IN THE REGION OF MESOPAUSE
XU Jiyao, WANG Yongmei, WANG Yingjian
1999, 19(3): 213-219. doi: 10.11728/cjss1999.03.213
Abstract(2059) PDF 430KB(842)
Abstract:
In this paper, the effect of gravity waves on the photochemical heating rate is studied. Calculation indicates that gravity waves can cause the loss of photochemical heating rate in mesopause. The influences of different background temperature profiles and atomic oxygen distribution on this process are also studied. The study indicates that as the decrease of background temperature and increase of the background distribution of atomic oxygen, the photochemical heating rate loss caused by gravity waves increase obviously.
TEST OF PHOTOCHEMICAL PROCESS OF MESOSPHERIC OZONE DURING THE TOTAL SOLAR ECLIPSE
WANG Yingjian
1999, 19(3): 220-225. doi: 10.11728/cjss1999.03.220
Abstract(2094) PDF 384KB(996)
Abstract:
This paper studies the variation of atmospheric ozone and O2(1△g) during total solar eclipse using the 1D time-dependent photochemical model of nitrogenhydrogen-oxygen atmosphere. And the test of photochemical models is made through the comparison with the observed data. The results show that the effective altitude of the variation of solar irradiance on 1.27μm airglow during total solar eclipse is obviously lower than that in twilight. The observed altitudes of atmospheric ozone during this total solar eclipse is about 52-67km from 1.27μm airglow emission and the observed increase of the ozone contents in Mohe is about 50% during the eclipse of March 9, 1997. It is consistent with the results of theoretical analyses of nitrogen-hydrogen-oxygen atmosphere. It exhibits no ozone deficit in the altitude of 52-67 km.
BISPECTRAL ANALYSIS OF THE MF RADAR WINDS
HU Xiong, Zhang Xunxie, Kiyoshi Igarashi
1999, 19(3): 226-231. doi: 10.11728/cjss1999.03.226
Abstract(2391) PDF 359KB(1494)
Abstract:
Bispectral analysis and dynamic spectral analysis are applied to the wind data of June, 1997, measured by MFradar in Yamagawa, Japan, to investigate nonlinear interactions among planetary waves, tidal waves and gravity waves in the mesopause region. Results show that there were strong diurnal tide, semi-diurnal tide and quasi-two-day wave activities, and some groups of three waves whose frequencies satisfied resonant conditions coexisted and their phases were coherent, which may suggest non-linear wave-wave interactions. Discussions on these nonlinear interactions between different kinds of waves are presented.
PROPAGATION CHARACTERISTICS OF LOW-LATITUDE Pi2 PULSATIONS IN EAST-WEST DIRECTION
YANG Shaofeng, DU Aimin, CHEN Baosheng, NING Xuerong, XIAO Fuhui, HONG Fuyuan
1999, 19(3): 232-238. doi: 10.11728/cjss1999.03.232
Abstract(1832) PDF 463KB(951)
Abstract:
An array of three low-latitude pulsation stations was established at Kashi, Anxi and Beijing near geomagnetic latitude 29.6°N (L = 1.3) from Oct. 10 to Nov. 29 in 1996. According to observation data, propagation and polarization characteristics of low-latitude Pi2 pulsations are studied. It is found that eastward propagation with right-handed polarization is dominant in dusk, westward propagation with left-handed polarization are dominant after 2000LT. There is a sudden change of propagation at 2230LT. 0000LT (midnight) is a demarcation line of major axes azimuth basically. NE-SWare dominant before the midnight. NW-SE are dominant after the midnight.
COMPUTER SIMULATION TO A TOP-HAT SEMISPHERIC ELECTROSTATIC ANALYZER
YU Dejiang
1999, 19(3): 239-246. doi: 10.11728/cjss1999.03.239
Abstract(1934) PDF 495KB(1095)
Abstract:
This paper describes a method to simulate a top-hat 90° electrostatic anajyzer numerically. Computer codes for this type of analyzer are developed and applied specifically to the computation of the top-hat analyzer prototype of Sablik et al. The potential distribution in the analyzer is found from solving a Laplace equation by using finite difference method; the motion equation of charged particles leads to the paths of these particles with time being parameter; the expressions of response functions and geometric factor are correctly derived; a scaling law of the analyzer behaviors is given, and is taken into account in the entire simulation. In comparison of the present results with those of Sablik et al, the accuracy of the present simulation computation is analyzed and assessed.
DECOMPOSITION KINETICS OF THREE KINDS OF ABLATIVE MATERIALS
LI Li, TAN Zhicheng, MENG Shuanghe
1999, 19(3): 247-252. doi: 10.11728/cjss1999.03.247
Abstract(1716) PDF 341KB(939)
Abstract:
The decomposition kinetics of three kinds of ablative materials is studied by means of thermogravimetric analysis TGA. The direct-solution method and difference method are applied to treat TGdata in order to derive the kinetic parameters from thermal analysis curves. By checking the experimental technique with CaCO3 samples of known decomposition kinetic parameters, it is found that the results obtained by the present research are in good agreement with those from the literature. The decomposition kinetic parameters of three kinds of ablative materials are determined by using both the direct-solution method and difference method.
THE PREDICTION OF GUIDE STARS IN THE FIELD OF VIEW
LIN Tao, QIAN Guohui
1999, 19(3): 253-259. doi: 10.11728/cjss1999.03.253
Abstract(2036) PDF 421KB(938)
Abstract:
The distribution of guide stars in the field of view (FOV), especially in case of considering the magnitude error, gives an important influence to the design of optical system of star tracker, the selection of guide stars and the star field recognition algorithm itself. In this paper, the distribution of guide stars in ideal cases is described and based on the threshold of magnitude and measured uncertainty, the prediction of distribution in case of considering the magnitude error is derived. A Monte Carlo experiment demonstrates that the statistical result is well coincided with the prediction by using above mentioned method.
ELECTRON DENSITY DISTURBANCE IN LOCAL IONOSPHERE CAUSED BY NOx EXHAUST PLUME
MA Yanhua, ZHAO Hua, CHEN Yiping
1999, 19(3): 260-265. doi: 10.11728/cjss1999.03.260
Abstract(2037) PDF 402KB(924)
Abstract:
The diffusive and photochemical processes of NOand NO2 exhaust plumes in Elayer during the daytime have been investigated and a spherical approximation is assumed for the plume diffusive process. NOexhaust plume in Elayer causes a temporal 7.5-fold increase of electron density ne, while NO2 exhaust plume gives rise to a 24-fold increase of ne as a result of photo-ionization and dissociative recombination reactions. The chemical reactions between molecules and ions become more and more important in Flayer and may lead to a temporal distinct decrease of ne after release of NO2 exhaust plume.
PREDICTION OF PROTON-INDUCED SINGLE EVENT UPSET
HAN Jianwei, YE Zonghai
1999, 19(3): 266-271. doi: 10.11728/cjss1999.03.266
Abstract(2177) PDF 296KB(1583)
Abstract:
According to the essentials of proton induced single event upset (SEU) and the characterastics of the high-energy proton in space, the present paper put forward a method for predicting proton-induced SEU. This method is based on the experiments of heavy ions. Using this method, predictions of proton-induced SEUfor several kinds of devices were made. It showed that the predictions agree well with the ground testing and flight observations.
ON THE INTEGRATED ANALYSIS OF OPTIMUM CONTROL DESIGN IN INTELLIGENT STRUCTURE SUBJECTED TO CONSTRAINT OF STRUCTURE OPTIMIZATION
YAN Yunju, JIANG Jiesheng
1999, 19(3): 272-278. doi: 10.11728/cjss1999.03.272
Abstract(2456) PDF 424KB(669)
Abstract:
Under the constraints to meet the requirements of dynamic features of structures, a hybrid optimizing algorithm is formed by minimizing the control energy and the structural weight. A 72 bars space truss with two piezoelectric actuators is used to illustrated the complete process of the algotithm. It is shown that the control energy and the structural weight are reduced obviously by using the proposed methods.
THE CURRENT CHARACTERISTICS OF A SOLAR FILAMENT WITH THE ELLIPTICAL SHAPE
LI Kejun
1999, 19(3): 279-283. doi: 10.11728/cjss1999.03.279
Abstract(1898) PDF 294KB(902)
Abstract:
In this paper, the vertical equilibrium equation of a current filament has been deduced with the assumption that the whole filament is of an elliptical shape. Then as an example, the relation between the current filament in the active region NOAA 131 and its balance altitude is investigated according to the equation. The characteristics of the equilibrium current are also discussed in this paper.
THE DISCONNECTION AND RIPPLING OF THE ION TAIL OF COMET HALE-BOPP
WANG Qi, YANG Jiexing, ZHANG Chunsheng, WU Yuezhen, WANG Min
1999, 19(3): 284-288. doi: 10.11728/cjss1999.03.284
Abstract(2412) PDF 319KB(648)
Abstract:
The observations of the large scale structure of Comet Hale-Bopp made around perihelion at Purple Mountain Observatory lead to the following results: 1) Some disconnection events occurred on Feb. 16, 17 and 18 in 1997.From these images it is concluded that the moving velocity of matter within the ion tail is about 50 km/s and the closing speed of a ray toward the main tail axis is 0.080'/s during the corresponding period of observations. 2) There is a rippling appeared in a beam of ion tail on March 3, 1997. Its phase velocity is about 200 km/s and its amplitude is about 0.2 million km. The width of this ion beam is 0.08 million km. The relevant data are obtained by means of PDSmeasurement.