Table of Content

    15 May 2013, Volume 33 Issue 3 Previous Issue    Next Issue
    Distribution of CMEs in different angular width and its relationship with the phase of sunspot numbers in solar cycle 23
    Meng Weijuan, Le Guiming, Lin Zhaoxiang, Zhang Yong, Yang Xingxing
    2013, 33 (3):  225-230.  doi: 10.11728/cjss2013.03.225
    Abstract ( 2280 )   PDF (489KB) ( 1381 )   Save

    In this paper we statistically analyzed the distribution of the numbers of CME with different angle width during the period of 1996-2008. Then we obtained the relationship between the number of CME with some typical angle width varying with time and that the sunspot numbers varying with time. The analytical results indicate that the numbers of CME within angle width 0° ~ 180° make up 95%, full-halo CMEs make up 2.83%, and the quantities of CME within angle width 301° ~ 359° make up very little proportion of all CMEs. The CMEs of angle width 0° ~ 60° have three peaks, which doesn't match the characteristics of sunspot numbers varying with time. There is no two-peak distribution of the numbers of CME within angle width 121° ~ 180°. Moreover, the distribution of full-halo CMEs has a typical two-peak structure, with the first peak appearing in 2001 and the second peak appearing in 2005, which is not synchronized with the distribution of sunspot numbers.

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    Study of magnetic reconnection between closed loops and open magnetic field driven by horizontal flows on solar surface
    Chen Wenlei, He Jiansen, WU S T, Yang Liping, Wang Aihua, Zhang Lei, Tu Chuanyi
    2013, 33 (3):  231-239.  doi: 10.11728/cjss2013.03.231
    Abstract ( 2143 )   PDF (1353KB) ( 1237 )   Save

    Numerous observational events in the solar atmosphere (e.g., solar flares and jets) are attributed to be the energy conversion due to magnetic reconnection. Magnetic reconnection is also involved in a new scenario of solar wind origin to play a crucial role in opening the closed loop and releasing its mass into the open funnel. In the scenario, closed loop are moved towards the supergranular boundary by the supergranular advection, colliding with open magnetic funnel there and triggerring magnetic reconnection between each other. This work aims at studying the occurrence and effect of magnetic reconnection in the scenario in details. Magnetohydrodynamic (MHD) numerical simulation is an important approach to investigate the magnetic reconnection process in the solar atmosphere. A 2D MHD numerical model in supergranular scale is established, which starts from the solar atmosphere with stratified layers of temperature and density. Based on quantitative analysis of the simulation result, the conclusion that the mass flow in the open funnel can be supplied from the closed loop aside through magnetic reconnection as driven by supergranular advection is suggested. Our results lay the foundation for future modeling of solar wind origin.

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    Trajectory method of 3D test particles in global transport in magnetosphere
    Cao Xin, LÜ Jianyong, Yang Zhiliang, Liu Ziqian, Yang Yafen, Zhao Mingxian
    2013, 33 (3):  240-249.  doi: 10.11728/cjss2013.03.240
    Abstract ( 2307 )   PDF (1687KB) ( 1002 )   Save

    Based on the theory of magnetospheric particle dynamics and the trajectory method of 3D test particles, we firstly verified charged particles' dynamic characters under a dipole field model for the inner magnetosphere situation (r < 8Re). Then, using a global MHD model as the magnetospheric background, the trajectory method of 3D test particles is employed to investigate the injection of solar wind ions into the magnetosphere during the southward IMF, and to simulate several different typical situations of the injection of the particle into the cusp region during the northward IMF. The simulation results not only reveals the possible processes of the particle injection into the cusp region for northward IMF, but also indicates the general distribution of the particles originally from the solar wind in the magnetosheath and magnetosphere, and the dawn-dusk asymmetry of the particles' density during the southward IMF. The simulation results are coincident with the theory and observation of magnetospheric dynamics. And for the first time, it is indicated by numerical simulation that an atypical magnetic mirror near the polar cusp region plays an important role in the particles' injection from the cusp region to ring current region during northward IMF.

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    Numerical computation of proton geomagnetic vertical cutoff rigidities on 7-8 November 2004
    Zhen Jie, Chu Wei
    2013, 33 (3):  250-257.  doi: 10.11728/cjss2013.03.250
    Abstract ( 2233 )   PDF (884KB) ( 1211 )   Save

    The geomagnetic cut-off rigidity can effectively measure the shielding effect of Earth's magnetic field on cosmic ray particles. In this paper, the single particle orbit theory is used to simulate the movement of cosmic ray protons in the Earth's magnetosphere and the specific location within the magnetic field along the vertical direction to the earth center. Based on the establishment of T04 and IGRF2000, the fourth-order Runge-Kutta method is used to simulate the trajectories of particles. The vertical cutoff rigidities of global cosmic protons around the height of 450km above Earth's surface at two moments in November 2004 are calculated. The value change of geomagnetic vertical cutoff rigidity with the magnetic latitude and magnetic longitude is analysed with the help of 684 calculation results at the same moment. The changes of protons vertical cutoff rigidity with the height from Earth's center, at the position of magnetic latitude of 30°, magnetic longitude of 0°, 45°, 90°, 135°, 180°, 225°, 270°, 315°, are also simulated. Simulation results show that the change of geomagnetic effective vertical cutoff rigidity with the increasing height from the Earth's center is getting more and more slow and slower along the sunny direction to the magnetic tail.

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    A Statistical Study on Seismo-Ionospheric Anomalies of the Total Electron Content for the Period of 56 M ≥ 6.0 Earthquakes Occurring in China During 1998-2012
    Liu J Y, Chen C H, Tsai H F, Le H
    2013, 33 (3):  258-269.  doi: 10.11728/cjss2013.03.258
    Abstract ( 2520 )   PDF (1006KB) ( 1434 )   Save

    This paper reports statistical results of Seismo-Ionospheric Anomalies (SIAs) of the Total Electron Content (TEC) in the Global Ionosphere Map (GIM) associated with 56 M ≥ 6.0 earthquakes in China during 1998-2012. To detect SIA, a quartile-based (i.e. median-based) process is performed. TEC anomalies for the period of earthquakes without being led by magnetic storms about 10 days are further isolated and examined to confirm the SIP existence. Results show that SIA is the TEC significantly decrease in the afternoon period 2-9 days before the earthquakes in China, which is in a good agreement with the SIA appearing before the 12 May 2008 M8.0 Wenchuan earthquake.

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    Analysis of variation characteristic of VTEC in the low latitude region during low solar activity
    Liu Guoqi, Gong Jiancun, Huang Wengeng, Shen Hua
    2013, 33 (3):  270-276.  doi: 10.11728/cjss2013.03.270
    Abstract ( 2607 )   PDF (562KB) ( 1111 )   Save

    Observational data obtained by an ionospheric scintillation and TEC monitor at Fuzhou (26.1°N, 119.3°E, geomagnetic latitude 14.4°N) during 2006-2010 is used to analyze the characteristic of temporal variation of vertical TEC in this region. The results show that the maximum value occurs at 06:00UT during spring, autumn and winter while at 08:00UT during summer, and the averaged minimum occurs at 21:00UT for all seasons. A seasonal anomaly of VTEC is found with the high value occurring during spring and autumn seasons while low value during summer and winter seasons; there is a weak winter anomaly of VTEC. The value in summer are relatively lower than that in winter and the occurrence time of maximum is delayed. VTEC reveals a decreasing tendency from 2006 to 2009 and increases during 2010, which is corresponding with the yearly variation of solar and geomagnetic activity. The correlation analysis exhibits that the variation of VTEC has a good relation with solar activities with a value of over 0.5, while it shows a weak relationship with the geomagnetic activity. Correlation between F10.7 and VTEC decreases with the raise of total value of geomagnetic index Kp Σkp.

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    Applicability analysis of IRI-2007 in predicting TEC over Guangzhou region
    Cai Chaojun, Huang Jiang, Deng Baichang, Xu Jie, Huang Linfeng, Quan Hongjun
    2013, 33 (3):  277-285.  doi: 10.11728/cjss2013.03.277
    Abstract ( 2353 )   PDF (785KB) ( 1125 )   Save

    By using GPS-TEC data observed in 2008 and IRI-TEC data derived from IRI-2007 model, the variations of Total Electron Content (TEC) are studied over Guangzhou (23.2°N, 113.3°E), which is in the equatorial anomaly region. Results show that the diurnal variation of GPS-TEC shows a peak value at about 16:00LT, while IRI-TEC is at about 15:00LT. The seasonal variation of TEC appears a winter anomaly and semiannual pattern, maxima in equinoxes and minima in summer and winter. A good agreement is found between IRI-TEC and GPS-TEC in daytime, but a bit large deviation in nighttime, and the IRI-TEC is in more agreement with the GPS-TEC when choosing NeQuick, B0 Table and URSI parameters. However, GPS-TEC shows apparent response to magnetic storm while IRI-TEC does not show any response to it. Through comparison, the applicability of IRI-2007 model in predicting TEC is analyzed over Guangzhou region, and the reasonable input options of parameters are also discussed.

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    Adaptive prediction of maximum usable frequency in high-frequency communication
    Liu Yanan, Liu Xuecai, Wang Jian, Lin Fajun
    2013, 33 (3):  286-292.  doi: 10.11728/cjss2013.03.286
    Abstract ( 2406 )   PDF (526KB) ( 1195 )   Save

    In order to realize the adaptive prediction of maximum usable frequency in high-frequency communication, Volterra adaptive method is introduced. Based on the oblique sounding data of chain from Qingdao to Xinxiang in March 2007 and 2012, single-step prediction in different solar activity years and short-term prediction of different steps and training samples length are conducted to validate accurateness, adaptability and validity of this method. Results indicate that the super short-term prediction adopting Volterra adaptive method has good agreement with oblique sounding data and this method is suitable for different solar activity periods. When the prediction step is not more than 1/12 period, RMSE is less than 0.79MHz. Comparison with prediction results of Lyapunov exponent method shows that Volterra adaptive method can gain upper precision in the situation of less data, time-varying channel etc., and the practical application is more convenient. The method provides a basis for in-depth study of high frequency prediction technology.

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    Effect of clinorotation on cellular structure, photosynthetic activity, carbohydrate and astaxanthin metabolism of Haematococcus pluvialis
    Zhang Yu, Hu Chunxiang, Zhang Delu
    2013, 33 (3):  293-301.  doi: 10.11728/cjss2013.03.293
    Abstract ( 2309 )   PDF (761KB) ( 1310 )   Save

    During 20 days of simulated microgravity using clinostat (two-dimensional), the cellular structure, photosynthetic activity, primary and secondary metabolism of Haematococcus pluvialis were investigated. Results showed that the cell shape appeared abnormal and the volume became smaller than the ground control's. Ultrastructure analysis revealed that the starch grains seemed smaller and the thylakoid membranes were more randomly distributed and loosened after 20 days of clinorotation. Chlorophyll content decreased during the early period of clinorotation, but increased in the late phase. Carotenoid content and photosystem II efficiency decreased during the whole clinorotation. It could be presumed that the decreased photosynthetic efficiency might have some relation with the decreased pigment synthesis and the structure changes that happened on chloroplast after clinorotation. The smaller starch grains, together with the decreased starch content were probably due to an increased hydrolysis of amylase during clinorotation. The increased sucrose and trehalose played a protective role in the accommodation to early clinorotation. However, this led to a decrease of glucose and fructose utilized for the synthesis of protective disaccharides. In the middle phase of clinorotation (i.e. the acclimation period), a compensatory synthesis of chlorophyll, glucose and fructose was observed, whereas synthesis of sucrose and trehalose reduced. The decreased astaxanthin production during the whole clinorotation was due to the depressed carotenoid participating in the astaxanthin synthetic pathway.

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    Autonomous Time-tag Error Measurement Applying Two Way Time Transfer for Earth Gravity Satellites
    Chen Li, Wang Yueke, Yang Jun, Zhang Chuansheng
    2013, 33 (3):  302-307.  doi: 10.11728/cjss2013.03.302
    Abstract ( 2012 )   PDF (501KB) ( 859 )   Save

    Autonomous time-tag error measurement is of importance for development of Chinese Earth gravity satellites. In this paper, Two Way Time Transfer (TWTT) method is introduced for the autonomous time-tag error measurement of gravity satellites. A measurement scenario is presented, and a model which includes satellite-motion-induced path asymmetry, ionosphere effect, instrument delay, and random time measurement error is built. Combining the characteristics of Earth gravity satellites adopting TWTT, the influences of above mentioned error sources are analyzed and the relevant correction methods are proposed. Take GRACE (Gravity Recovery And Climate Experiment) system for example, based on the TWTT method with correction means, the achieved measurement precision of autonomous time-tag error can be better than 0.62ns, most of which is induced by the calibration error of instrument delay and the random time measurement error.

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    Research of star map display and control system on very high accuracy star simulator
    Sun Gaofei, Zhang Guoyu, Wang Lingyun, Gao Yujun, Wang Xiangdong
    2013, 33 (3):  308-312.  doi: 10.11728/cjss2013.03.308
    Abstract ( 2407 )   PDF (490KB) ( 1090 )   Save

    In order to conduct ground calibration and accuracy testing for very high accuracy star sensor, a very high accuracy star simulator is put forward, which simulation accuracy is better than 0.5". Star map display and control system is the key component of the star simulator. According to the requirement of simulation accuracy, the star plate is proposed to be used as a map display device. By using a luminescence apiece controllable LED array as the target illumination system, the very high accuracy star map is simulated successfully. At the same time, the software is developed to control each LED light out/on and its gray value, which has completed the transformation for star map and magnitude simulation. Experimental results show that the map display can reach a precision less than 0.5", and can realize dynamical change and magnitude simulation, which has been able to meet the requirement of very high accuracy of star sensor ground calibration and accuracy testing.

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    Research on optical autonomous navigation for approach phase of Mars exploration
    Cui Wen, Zhang Shaoyu, Zhang Shuyu, Baoyin Hexi
    2013, 33 (3):  313-319.  doi: 10.11728/cjss2013.03.313
    Abstract ( 2341 )   PDF (551KB) ( 1220 )   Save

    The optical autonomous navigation has recently become one of the key topics in interplanetary space missions. According to the current research literature, most people only focused on the application of optical autonomous navigation for the cruise phase or the approach phase of asteroids exploration. The research for the approach phase of planets is rare. Based on the upcoming Mars exploration program of China, with the research of dynamics model, observation model and filtering algorithm, the process of the optical autonomous navigation during the Mars approach phase is studied. Through the observability analysis of the navigation system, the feasibility of using Mars optical information only for autonomous navigation is proved. Simulation result showed that the total time of the optical autonomous navigation for approach phase is about 40 hours. In the last 5 hours, the filtering results are becoming stable. The overall position error is less than 40km, and the velocity error is 0.25m·s-1. The stability and accuracy of the results can meet the requirement of actual task, and is referencable for Chinese Mars exploration program.

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    Surveying performance analysis of the new generation satellite navigation signals
    Wang Mengli, Chen Jinping, Ma Zhiqi
    2013, 33 (3):  320-324.  doi: 10.11728/cjss2013.03.320
    Abstract ( 2048 )   PDF (425KB) ( 1075 )   Save

    Surveying performance of navigation signal affects the precision of position, velocity and timing, and it is one of the important factors for system design. Combining with the new signals system frame design of COMPASS, measuring precisions of pseudorange, carrier phase and Doppler frequency of new generation satellite navigation signals are analyzed, and numerical calculation is carried out taking typical design parameters as example. Results indicate that all the signals can achieve the following surveying performances under typical receiver design parameters and using environments: 0.1m of pseudorange precision, 0.006 cycles of carrier phase precision and 0.005m·s-1 of Doppler frequency precision. The study can offer references for the design of satellite navigation system signals, the key parameters design of navigation receivers and the budget of user ranging errors.

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    Calibration of electron analyzer for Mars exploration
    Zhang Aibing, Kong Linggao, Wang Shijin, Sun Yueqiang, Zhu Guangwu, Li Lei, Zheng Xiangzhi
    2013, 33 (3):  325-330.  doi: 10.11728/cjss2013.03.325
    Abstract ( 1832 )   PDF (511KB) ( 817 )   Save

    A concentric cylindrical electrostatic analyzer with deflection plates was used in the electron analyzer for Mars exploration. This sensor scheme met both the requirements of performance and miniaturization. The electron analyzer was calibrated at the Center for the Study of Radiation in Space (CESR) in France. The electrostatic analyzer factor, energy resolution, deflection factor of deflection plates, resolution of azimuth angle and resolution of elevation angle for both channels was calibrated. Results of calibration were given and further analysis was carried out. It is shown that energy range, energy resolution, field of view and resolution of azimuth angle are better than the performance requirements. The results lay the foundation for data processing and data analysis, setting the operating parameters of electron analyzer in orbit.

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    Study on the technique of rapid decontamination for Langmuir probe in orbit
    Liu Chao, Wang Shijin, Sun Yueqiang, Liang Jinbao, Guan Yibin, Han Ying
    2013, 33 (3):  331-336.  doi: 10.11728/cjss2013.03.331
    Abstract ( 2249 )   PDF (589KB) ( 1091 )   Save

    A technique for rapidly removing the surface contamination from in orbit Langmuir probe is presented. As an important technique for in-suit detection of the space plasma, the Langmuir probe has been widely used in a variety of spacecrafts. When surface of the probe sensor is contaminated, deviation of the Langmuir probe's I-V characteristics curve will be caused, which then results in the plasma parameters' inaccuracy by the detection. In this paper, it has been proved by tests that loading the probe sensor with high voltage can remove the sensor surface contaminants quickly and effectively, which can ensure the real-time accurate space plasma parameters detection by Langmuir probe in orbit.

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    Image matching analysis and experiment of spaceborne camera swayed in the end of orbit life
    Yang Xiubin, Jiang Li, Jin Guang
    2013, 33 (3):  337-345.  doi: 10.11728/cjss2013.03.337
    Abstract ( 2174 )   PDF (780KB) ( 1343 )   Save

    Satellite sways matching image is established by analyzing the bottlenecks problem of that the data read-out frequency is too large, and the serious mismatch shift which spaceborne TDI CCD camera might face in the end of orbit life. Based on orbital decay height, the model of swaying match image is designed, the relation between orbit height and angle of the matching image is calculated, quantitative analysis on the feasibility of image motion vector, deviant angle, image distortion are carried out, and then satellite attitude pointing accuracy and stability which meet the requirement of imaging are analyzed through Monte Carlo methods. Finally, physical simulation of TDI CCD camera swaying-imaging is conducted on the mini-type three-axis air bearing table constructed for attitude control simulation of small satellite. Simulation results suggest that the MTF simulation and cross-correlation function of the similarity measurement are both more than 0.85, and satellite swaying to match image can meet the imaging requirement well in the end of the orbit life.

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    Optimum design based on full stress ruler and test for truss of space camera
    Jia Xuezhi, Zhang Lei, Jin Guang
    2013, 33 (3):  346-352.  doi: 10.11728/cjss2013.03.346
    Abstract ( 1873 )   PDF (911KB) ( 1279 )   Save

    Since it is hard to design the truss structure in space camera which has both low weight and high stiffness, the rule of full stress is proposed to optimize the truss section. The design rule and request of the optical system are introduced. By selecting the truss weight as the optimization object, gravitation transmutation and first frequency of secondary mirror as the restriction condition, and the inside and outside diameters of truss section as the optimization variables, the optimization model based on full stress rule is established. The optimized inside and outside diameters of truss section are 40mm and 50mm respectively, the optimized weight of truss is 6.3kg, while the first frequency is 121Hz. The mode analysis, gravitation transmutation analysis and temperature raise of 15℃ analysis later indicate that the truss optimized can satisfy the needs of the optical system. Finally, 0.2g vibration test and dimensional stability test are inflicted to the truss, which shows that the first frequency of the truss is 119Hz, and that the transmutation of the secondary mirror is less than 5". The truss optimized has the characteristic of compact structure and fine dimensional stability which meet the needs of space camera well. It lays a foundation for development of space camera with large caliber, long focus and light weight.

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