2011 Vol. 31, No. 5

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Solar Variation and Global Climate Change
ZHANG Liang, WANG Chi, FU Suiyan
2011, 31(5): 549-566. doi: 10.11728/cjss2011.05.549
Abstract(2558) PDF 1416KB(2027)
Abstract:
The Sun continually radiates electromagnetic wave and particles to Earth, and the solar radiation is the main energy resource for the Earth’s climate system. The response of climate system to the solar variation is very complex, including radiative process, dynamic process and microphysics process. This paper reviews the measurements from satellites and reconstruction results by other proxies of the solar irradiance variation, enumerates some climate observational evidence in the fields of paleoclimate, temperature, atmospheric circulations and clouds affected by the solar activity. The three main possible mechanisms by which the solar variation may influence the global climate include: the variability of total solar irradiance could change the earth surface temperature, and thus change the atmospheric circulation via the ocean-atmosphere couple; the solar ultra violet radiations modulate the stratospheric temperature and wind field by heating ozone, and the stratosphere response could then affect the lower troposphere by stratosphere troposphere coupling; the solar modulates galactic cosmic ray through interplanetary magnetic field, and galactic cosmic ray may change the cloud cover via ionizing the atmosphere, which could further change the earth’s energy budget.
Theoretic Study on Formation and Variation of Magnetopause of Planet (Mars)
SHI Jiankui, CHENG Zhengwei, WANG Shengguo, ZHANG Tielong, LIU Zhenxing
2011, 31(5): 567-572. doi: 10.11728/cjss2011.05.567
Abstract(2599) PDF 491KB(1019)
Abstract:
However, Mars has not intrinsic magnetic field according to the observation. Therefore, the Martian magnetosphere formation is different from the Earth’s. As we know, Mars has an induced magnetosphere. In this paper, to consider the balance between solar wind dynamic pressure and the planetary ionospheric charged particle pressure companying with a weak intrinsic magnetic field pressure, a model for formation of planet (Mars) magnetopause is established. According to the satellite observation, configuration of the dayside Martian magnetopause and its variation in the meridian planes are studied with the model. The results show that the configuration of the dayside Martian magnetopause has some similarities to the geo-magnetopause. The stronger the solar wind dynamic pressure is, the closer the Martian magnetopause to the Mars surface will be. The weaker the solar wind dynamic pressure is, the farther the Martian magnetopause to the Mars surface will be. According to the view that the Martian intrinsic magnetic moment is reducing from ancient times to the present and it would be reversed, the role of the large scale magnetic field to the Martian magnetopause is studied with an assumed intrinsic magnetic moment. Results show that the stronger the intrinsic magnetic moment was, the further the Martian magnetopause to the Mars surface would be. The weaker the intrinsic magnetic moment was, the closer the Martian magnetopause to the Mars surface would be. These results are significant not only to study the long term variation of the Martian magnetosphere, but also to study the configuration of magnetopause in general planet.
Research in Solar Dynamo Theories
WU Jianqing, YANG Zhiliang
2011, 31(5): 573-586. doi: 10.11728/cjss2011.05.573
Abstract(2926) PDF 939KB(1308)
Abstract:
Various activities of the Sun, such as flare, coronal mass ejections, solar wind, which will affect the normal work of satellites, radio communication and electric power system. Therefore, researching the activities of the Sun has great significance for human. Moreover, these activities are dominated by the magnetic field. The purpose of study the solar dynamo theories is not only to unpuzzle the correlation and variation among various activities, but also to explain the origin and character of the magnetic fields on the Sun. The paper briefly reviews the relevant observational data pertaining to sunspots and solar cycle first and researches evolution if the solar dynamo theories. Then the three basic elements of the dynamo, the differential rotation, meridional circulation and magnetic diffusivity, with the fundamental equations of magnetic field generation are introduced. Magnetic induced equation is the first basic equation for dynamo theories and the first item of induced equation is from Ohm s law. What s more, mean field dynamos which contain Babcock-Leighton dynamo, interface dynamo and flux transport dynamo, non-axisymmetric dynamo, MHD simulation and small scale dynamo are described. The advantages and shortcomings of them are presented respectively. Finally, the existing problems and possible development in the future for solar dynamo theories are suggested.
TC-1 and Geotail Joint Observations of Magnetic Disturbances in the Near-Earth Plasma Sheet During Substorm
DUAN Suping, LIU Zhenxing, LU Li, ZHANG T L, REME H
2011, 31(5): 587-595. doi: 10.11728/cjss2011.05.587
Abstract(2551) PDF 642KB(1018)
Abstract:
On the basis of joint observations of TC-1 at about -12.5Re and Geotail at about -8 ～ -9Re in the near-Earth plasma sheet in the magnetotail, the plasma instabilities in the vicinity of substorm onset occurred at about 02:53:20UT on 28 September 2004 were investigated. The observation results indicate that (1) the location of substorm onset triggering region is small within the inner plasma sheet in the near-Earth magnetotail, (2) the lower-hybrid instability is incited in the substorm triggering region and the lower-hybrid waves with the quasi-perpendicular propagation occur during substorm onset, (3) the magnetic dipolarization and the magnetic disturbance in the outside of near-Earth plasma sheet are very weak during substorm onset. The multiple magnetic dipolarization with different feature took place during substorm onset and substorm expansion phase. Key words Plasma sheet, Substorm, Magnetic dipolarization, Magnetic disturbance
Observations of the Ionosphere Effects of the Solar Eclipse on July 22, 2009
HU Xiong, WU Xiaocheng, XU Qingcheng, MA Guanglin, TU Cui, YAN Zhaoai, CHEN Xuxing, XIAO Cunying, ZHAO Mingliang, GONG Jiancun
2011, 31(5): 595-601. doi: 10.11728/cjss2011.05.595
Abstract(2993) PDF 579KB(1262)
Abstract:
For the first time, Langfang Medium-Frequency (MF) radar was used to simultaneously observe the ionospheric effects due to the solar total eclipse on July 22, 2009, with three GPS/TEC receivers operated at Wuhan, Jiaxing and Langfang respectively. Results show that during the solar eclipse, the D layer electron densities at 78km level observed by the MF radar decreased by 67% and the altitude level of equivalent electron densities of 200cm?3 uprising about 10 km. The ionospheric Total Electron Content (TEC) observed by the GPS/TEC receivers in the above three sites respectively decreased about 1TECU. Their minimum reductions of the D layer electron densities and TEC are synchronous with the solar eclipse maximum phase. After the solar eclipse, a Traveling Ionospheric Disturbance (TID) was revealed with a period of larger than 2 h in the GPS/TEC data.
Real-time Monitoring of Ionosphere Changes in the Shanghai Region by GPS Technology
WANG Hu, WANG Jiexian, BAI Guixia, ZHU Weidong
2011, 31(5): 602-606. doi: 10.11728/cjss2011.05.602
Abstract(2604) PDF 525KB(1316)
Abstract:
A method of real-time monitoring ionosphere based on GPS technology is described in this paper. The regional ionosphere model is constructed using GPS phase-smoothed pseudorange measurements. The ionosphere delay and instrumental bias are also calculated. Because the instrumental bias is stable, its value can be obtained after a period of time. Using this value, realtime instrumental bias can be forecasted. After deducted the instrumental bias from GPS signal, the real-time ionosphere information can be extracted in path of signal propagation. To validate this method, the data of Shanghai regional GPS network are used and a real-time regional ionosphere model is created. The results show the internal precision of this regional ionosphere model are better than 3TECU.
Disturbance of O+ Density Before Major Earthquake Detected by DEMETER Satellite
OUYANG Xinyan, ZHANG Xuemin, SHEN Xuhui, HUANG Jianping, LIU Jing, ZEREN Zhima, ZHAO Shufan
2011, 31(5): 607-617. doi: 10.11728/cjss2011.05.607
Abstract(2708) PDF 1631KB(1207)
Abstract:
Based on the data observed by French DEMETER satellite, this paper analyzed anomalies which may be caused by Ms7.9 Tonga Islands earthquake (3 May 2006). Perturbations of electric field and plasma parameters above epicenter from observations six days, two days and one day before the earthquake can be seen by visual interpretation of level-2 images. The amplitude and duration of perturbations increased when the earthquake was approaching. Perturbation was also recorded two days after the earthquake and its amplitude was still large. The variation feature of O+ density was more obvious than that of H+ and He+ density, and O+ accounted for about 90% among total H+, He+ and O+ through analyzing the data detected by IAP (Plasma Analyzer Instrument) onboard DEMETER satellite which has a revisiting period of sixteen days. Compared with the revisiting orbits of a half orbit one day before the earthquake from 2006 to 2008, it was found that variations of O+ density can be classified into three types: density in northern hemisphere is higher than that in southern hemisphere in summer; the situation is quite the contrary in winter; and O+ density is almost equal in both southern and northern hemisphere in equinoxes season. This paper presented different effects on O+ density under influence of earthquake and geomagnetic storm. The earthquake affects the distribution of O+ density at an orbit close to the epicenter, while geomagnetic storm affects O+ density at all orbits in a storm day. O+ density increased 20% more at the orbit closest to the epicenter than the other orbits one day before the earthquake, and it increased nearly an order of magnitude referred to the mean of O+ density in May from 2006 to 2008. In addition, we obtained electron density detected simultaneously by ISL onboard DEMETER at the above-mentioned revisiting orbits and discovered that electron density increased synchronously with O+ density. The increment of plasma density may be related to the electric field anomaly which resulted from the earthquake and led to modification of ionospheric structure.
Investigation and Application of FCA Method for Langfang MF Radar Wind Retrievals
MA Guanglin, HU Xiong, XU Qingchen, XIAO Cunying
2011, 31(5): 618-626. doi: 10.11728/cjss2011.05.618
Abstract(2678) PDF 977KB(1103)
Abstract:
Medium Frequency (MF) radar is one of the significant ground-based instruments for the horizontal wind measurements over the height range of 60～100km in the near-space. The Full Correlation Analysis (FCA) is the mainly used method to get wind velocity for MF radars with the Space Antenna Mode (SAM), which was introduced in details in this paper. Based on the antenna configuration of Langfang MF radar, the FCA algorithms with 3 antenna and 4 antenna called FCA-3A and FCA-4A respectively, were developed. The rejection criteria for FCA algorithm were also discussed and given. The algorithms were applied in the processing of the raw data of Langfang MF radar to compute wind velocity. The wind results were compared with those calculated by the ATRAD FCA software which was used in many MF radar sites in the world and it was shown that they are consistent with each other. The wind velocities estimated with the FCA-3A method agreed very well with those with the FCA-4A method. Results show that the algorithms of FCA-3A and FCA-4A are reliable for Langfang MF radar data processing.
Bone-specific Transcription Factor Runx2 on the Role of Antagonistic Bone Loss In Space
GUO Feima, DAI Zhongquan, WU Feng, SHANG Peng, LI Yinghui
2011, 31(5): 627-634. doi: 10.11728/cjss2011.05.627
Abstract(2605) PDF 839KB(1213)
Abstract:
To construct a stable expression of Runx2 in C2C12, MG63 cells, and primarily investigate the role of Runx2 against bone loss induced by spaceflight. Myoblast C2C12 and pre-osteoblast MG63 was transfected with Runx2 and selected overexpressing cell clone with G418. The stably transfected C2C12, MG63 cell lines with Runx2 were identified by westernblot and named C2C12-Runx2 and MG63-Runx2 respectively. The expression of genes regulated by Runx2 were determined using Real-time Quantitative PCR. The stable cell lines and untransfected cell lines were cultured in clinostat to simulate microgravity condition and detected the expression of Runx2 and its downstream genes by Real-time Quantitative PCR. C2C12-Runx2, MG63-Runx2 cell lines were gained which were overexpressing Runx2. The mRNA expression level of Alkaline Phosphatase (ALP) and Col1a1 increased in C2C12-Runx2 andMG63-Runx2 cells. The mRNA expression of ALP and Col1a1 decreased in the clinorotation group compared with the control group in MG63, C2C12-Runx2 and MG63-Runx2 cells. The decreased degree of ALP, Col1a1 mRNA expression in both transfected cell lines was lower than in untransfected cell lines under simulated microgravity condition. C2C12-Runx2, MG63-Runx2 cell lines were successfully constructed. The data from clinorotation and Real-time Quantitative PCR suggest that Runx2 can partly antagonize the decreased expression of osteogenic specific molecules induced by simulated microgravity.
Development of the Microgravity Experimental Device for Pulverized Coal Combustion
YU Qiang, AI Guozhi, WU Le, XU Minghou
2011, 31(5): 635-639. doi: 10.11728/cjss2011.05.635
Abstract(2455) PDF 518KB(1225)
Abstract:
A facility that can be used for pulverized coal combustion experiment in microgravity is described. It is used to study pulverized coal particles’ pyrolysis, gasification, ignition, volatile release, char combustion and burnout, and other combustion characteristics in microgravity. The pulverized coal is blown into the furnace chamber intermittently. When the temperature reaches the set point, turn on the valve and put pulverized coal into the furnace chamber, and then observe whether pulverized coal can be ignited so as to determine the ignition temperature of pulverized coal. By detecting the coal gases in the combustion, the volatile changes in precipitation of char combustion and the burnout characteristics can be attained. The flame structure and flame temperature distribution can be recorded by CCD image. The structure, the working principle and the experimental results of this facility are introduced. Further improvements of the facility are presented.
SPORT Satellite Configuration Design
YANG Xuan, YANG Hua, LIU Yuan
2011, 31(5): 640-646. doi: 10.11728/cjss2011.05.640
Abstract(2884) PDF 748KB(1115)
Abstract:
Two patterns of satellite configuration designs related to two forms of antenna unit have been given, according to the demand of SPORT satellite payload detection, the principles of satellite design and configuration layout design, and the constrained conditions of satellite configuration layout from delivering. Payload visual layout of satellite platform has been provided. Location and direction of payloads in the satellite have been determined, which can avoid interference and blocking between the payloads, in favor of observing the work space of payloads. The way to achieve scientific objectives has been initially identified, providing basis for satellite platform design. The feasibility study has verified that both patterns can meet the needs of SPORT satellite payload detection.
Fault Diagnosis of Satellite Based on IMM and Moving Horizon Estimation
ZHAO Shilei, WU Lina
2011, 31(5): 647-652. doi: 10.11728/cjss2011.05.647
Abstract(2538) PDF 482KB(1487)
Abstract:
This paper studies the fault diagnosis problems of the satellite attitude control system. Since the satellite works in space, the attitude control system of satellite is easy to be effected by uncertainties and disturbances in the harsh working environment. Interacting Multiple Model (IMM) is one of the effective fault diagnosis methods of the satellite control system but it is subjected to strong noise or wrong data. For this reason, this paper proposes to combine the moving horizon estimation instead of the Kalman filter with the IMM algorithm. The moving horizon estimation, which adopts not the estimation error of one time but the interval estimation error of a time span, is used to estimate the system states and the transition probabilities. So it could effectively decrease the influences of the wrong data or strong noise. Finally, the mathematical simulation results for diagnosis problem of the satellite attitude control system are presented to show the effectiveness of the proposed scheme.
Sun Polar Probe Trajectory Design Based on Multi-objective Genetic Algorithm
LI Xiaoyu, ZHENG Jianhua, WU Xia, GAO Dong
2011, 31(5): 653-658. doi: 10.11728/cjss2011.05.653
Abstract(3150) PDF 587KB(1039)
Abstract:
Solar polar probe is of great importance for space physics and the forecast of space weather, but to reach that goal of high solar inclination needs a huge amount of energy. Thus the trajectory of low-thrust and gravity-assist is often used for the sake of energy. In this paper, Jupiter was chosen to be the gravity-assist planet because of its powerful gravitation and the successful experience of Ulysses Probe launched by NASA. Only interplanetary low-thrust transfer stage and gravity-assist stage were considered and linked according to the patched conic approach at the initial design stage, with Earth escape stage being neglected. Low-thrust trajectory was modeled by the so called nominal trajectory concept with linearization about the Kepler orbit, further being analyzed by optimal control using state transmition matrix. In order to reach the goal of high solar inclination, the gravity-assist at Jupiter was modeled and an adjunct angle was defined to confirm the effect of gravity-assist to reach the high solar inclination. Multi-objective genetic algorithm was applied to optimize the two indices being established for energy saving of low-thrust interplanetary transfer and the high solar inclination for the Jupiter gravity-assist. Two optimal schemes were chosen from the final population, whose trajectory parameters are analyzed afterwards. Results showed that multi-objective genetic algorithm was compatible to find promising trajectory scheme of low-thrust gravity-assist trajectory to achieve the demands of solar polar probe mission.
Research of Ambiguity Solution in CEI-based Orbit Determination
LI Xiaojie, DU Lan, HUANG Jin
2011, 31(5): 659-665. doi: 10.11728/cjss2011.05.659
Abstract(2470) PDF 485KB(2342)
Abstract:
Connected-Element Interferometry (CEI) was a passive angular tracking method with the merits of high phase precision, flexible network distribution and nearly real-time processing due to short length of baselines. Firstly, feasibility of ambiguity solution in CEI-based orbit determination for GEO was analyzed. Integer ambiguity must be primarily solved in the orbit determination for TDRS because of its low initial orbit precision. It could be calculated by the high precise range measurement if the master control station could obtain range measurement, while the method of parameter estimation by fixing integer ambiguity was used without high precise range measurement. The simulation results indicated that this method was effective when the systematic error was less than 1.0m. The orbit determination precision for the satellite belt between 80°E and 140°E was gained, when the systematic error was 0.1m, along-track positional error component of the 110°E satellite reached 25 m, while 82m and 34m respectively for the 80°E satellite and 140°E satellite.
Applications of GPS on Meteorological Rocket Telemetry and Tracking
SHI Dongbo, WEI Feng, ZHANG Yu, WANG Lianzhong
2011, 31(5): 666-669. doi: 10.11728/cjss2011.05.666
Abstract(2316) PDF 418KB(731)
Abstract:
A new tracking system composed of GPS global positioning system, antenna cloud platform and wide lobe antenna has been introduced. In traditional tracking systems, there is a time difference between the tracked position information and received position information, and the antenna cloud platform needs an inversion of 359° when it rotates to the phrase point. Besides these problems, traditional tracking systems may lose the target because of the theoretical trajectory error, and after the separation of meteorological rocket sonde, how to track it before the first positioning is also a problem that needs to be figured out. This new tracking system has solved all problems stated above as well as how to keep tracking the target after losing it, and has successfully performed the telemetry tracking of meteorological rocket sonde in the Meridian Project. Attributing to its small size, portability, easy operation, low cost, and favorable maneuverability and reliability, the new system has many advantages comparing with the traditional radar tracking mode.
Broadband Signal Processing for Deep Space Array Network Based on Frequency-domain Beamformer
HU Shengbo, MENG Xin, YAO Xiujuan
2011, 31(5): 670-674. doi: 10.11728/cjss2011.05.670
Abstract(2473) PDF 497KB(1111)
Abstract:
Deep space communications have entered a new era of high speed transmission. Based on the deployment of large arrays of small antennae within radio astronomy community, Deep Space Array Network (DSAN) has become the final means for high speed transmission of deep space network. Based on the FX correlator, the architecture of frequency domain beamformer which has integrated array signal forming with correlate processing is presented. The method presented in this paper is to break up the signal into different frequency channels and analyze each frequency channel separately to obtain phase and delay feedback information. The method would be a significant step forward in both performance and complexity, which has great flexibility and robustness, and can support multi-missions. Finally, the key techniques of analysis-synthesis filtering, sub-array signals coherent forming, and adaptive variable fraction delay are described.
Design and Implementation of Electrostatic Levitation Position Control System
ZHOU Yangyang, WEI Ren, WANG Chao, SUN Zhibin, CAI Shijie, ZHAI Guangjie
2011, 31(5): 675-681. doi: 10.11728/cjss2011.05.675
Abstract(2143) PDF 643KB(1155)
Abstract:
Electrostatic levitation position control system is the core technology of electrostatic levitation material processing apparatus. In order to solve this problem, the basic conditions of stable levitation are analyzed. Three-dimensional position of the sample is measured by using two orthogonal parallel light beams with different wavelengths as light sources, and Position Sensitive Detectors (PSD) as position signal receiver. The Proportion Integration Differentiation (PID) position feedback control system is set up by using position signal as input and analog voltage as output. The output of the PID feedback control system drives the voltage amplifier to control the strength of the electric field according to position change of the sample. By choosing proper parameters of PID, the sample is well stabilized in the electrostatic levitation system.
Calculation on Radar Cross Section of Plasma-column Antenna Using JEC-FDTD Method
CHEN Wenbo, LI Sheng, GONG Xueyu
2011, 31(5): 682-686. doi: 10.11728/cjss2011.05.682
Abstract(2414) PDF 523KB(1058)
Abstract:
The paper has founded the 2D model of plasma antenna and JE convolution Finite-Difference Time-Domain (JEC-FDTD) algorithm is applied to the study on the antenna scattering characteristics based on the model. The effects of plasma density, collision frequency and glass tube on the Radar Cross Section (RCS) of the plasma antenna were analyzed in the paper. The analyze results show that RCS of plasma antenna can greatly decrease with the collision frequency increasing and plasma density decreasing. On the other hand, when the plasma antenna work at high frequency, the glass tube also has impact on the antenna scattering characteristics. Accordingly increasing in thickness of glass tube and enlargement of permittivity of glass will make RCS of the antenna decrease. So the stealth performance of plasma antenna can be improved by choosing the suitable plasma parameter and materials of glass tube based on the work frequency.
Electro-magnetic Performance Research on Tetrahedron Truss Antenna
SHOU Jianjun, XU Yan, GUAN Fuling
2011, 31(5): 687-692. doi: 10.11728/cjss2011.05.687
Abstract(2432) PDF 530KB(1105)
Abstract:
Large deployable truss antennas have extensive applications in communication satellites and space stations. This paper deals with a kind of deployable truss antenna that consists of tetrahedral modules. Electro-magnetic performance of tetrahedron truss deployable antenna is researched, to optimize design parameter and structure precept. According to the features of the deployable reflector configuration and the geometry optical theory, the computing arithmetic of the electro-field intensity of the tetrahedron truss antenna is formulized. Then the paraboloid reflector is separated to form rectangular grid on the aperture plane and the integral of the far-field is conducted with the analytical method. Finally far-field pattern of antenna reflector is obtained. The corresponding program is designed and used to analyze far-field pattern of truss antenna with different design parameter. This method directly related the structure with the electro-magnetic field, which improves the design by leaving out the RMS value. So the design process is more accurate. This program can be applied to analyze the reflector radiation field of standard reflector or any reflector which distortion is already described.

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