2013 Vol. 33, No. 6

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Magnetospheric Boundary Layer Structure and Dynamics as Seen From Cluster and Double Star Measurements
Y V Bogdanova, C J Owen, M W Dunlop, M G G T Taylor, A N Fazakerley
2013, 33(6): 577-603. doi: 10.11728/cjss2013.06.577
In this review, we discuss the structure and dynamics of the magnetospheric Low-Latitude Boundary Layer (LLBL) based on recent results from multi-satellite missions Cluster and Double Star. This boundary layer, adjacent to the magnetopause on the magnetospheric side, usually consists of a mixture of plasma of magnetospheric and magnetosheath origins, and plays an important role in the transfer of mass and energy from the solar wind into the magnetosphere and subsequent magnetospheric dynamics. During southward Interplanetary Magnetic Field (IMF) conditions, this boundary layer is generally considered to be formed as a result of the reconnection process between the IMF and magnetospheric magnetic field lines at the dayside magnetopause, and the structure and plasma properties inside the LLBL can be understood in terms of the time history since the reconnection process. During northward IMF conditions, the LLBL is usually thicker, and has more complex structure and topology. Recent observations confirm that the LLBL observed at the dayside can be formed by single lobe reconnection, dual lobe reconnection, or by sequential dual lobe reconnection, as well as partially by localized cross-field diffusion. The LLBL magnetic topology and plasma signatures inside the different sub-layers formed by these processes are discussed in this review. The role of the Kelvin-Helmholtz instability in the formation of the LLBL at the flank magnetopause is also discussed. Overall, we conclude that the LLBL observed at the flanks can be formed by the combination of processes, (dual) lobe reconnection and plasma mixing due to non-linear Kelvin-Helmholtz waves.
Flux and Spectra of Primary Cosmic Rays at Yangbajing With the AMS-01 Experiment
Zhu Fengrong, Ran Zheng, Xu Lijun, Gao Linchao, Liang Hanxiao, Shi Yali, Jia Huanyu
2013, 33(6): 604-607. doi: 10.11728/cjss2013.06.604
Abstract(951) PDF 498KB(2095)
Based on AMS-01 experiment, the integral fluxes and the energy spectra are investigated for the estimation of background cosmic ray radiation. Using the data from AMS-01 experiment in the Sun quiet phase of June 1998, the integral fluxes of primary protons for the kinetic energy ranges of 0.44~4.31GeV, 4.31~12.38GeV, 12.38~199.06GeV near the Earth at geomagnetic latitude of Yangbajing are achieved respectively. And the integral fluxes of primary for the kinetic energy ranges of 6.92~14.45GV and 14.45~229.9GV are also obtained. Correspondingly, the energy spectra functions for the protons and helium are then fitted for this 5 energy ranges, separately. The integral fluxes for the same energy range above is consistent by the two methods of approximate calculation of integral and the integral of function curves.
Characters of the Pc3-4 Magnetic Pulsations at Middle and Low Latitudes: Preliminary Geomagnetic Results From Chinese Meridian Project
Zhang Qingmei, Wang Chi, Li Hui, Li Chuanqi
2013, 33(6): 608-616. doi: 10.11728/cjss2013.06.608
The characters of the Pc3-4 magnetic pulsations and their relationships to interplanetary conditions were studies during the periods of both the magnetic quite (March 20 to 27, 2011) and storm (September 25 to October 1, 2011), using ground-based geomagnetic field measurements from the new-developed Chinese Meridian Project. Preliminary results show there exist significant dawn-dusk asymmetric distribution of the Pc3-4 pulsations in the middle-low latitudes (1.3<L < 2.3), with Pc3-4 pulsations activity are observed mainly in the pre-noon sector, during both time periods. They are closely related to the interplanetary conditions, with high-speed solar wind and solar wind dynamic pressure pulsation leading to enhancement of the Pc3-4. However, Pc3-4 pulsations activity is not observed near the equatorial low latitudes (L <1.3) due to latitudinal effect.
Calculation Method for Geoelectric Field in Mid- and Low-latitude Area Based on Sparse Geomagnetic Data
Wu Weili, Liu Lianguang
2013, 33(6): 617-623. doi: 10.11728/cjss2013.06.617
Mastering spatial and temporal distribution of geoelectric field is the premise of researching and preventing adverse effect on technology systems due to geomagnetic induced current. This paper presents a model for geoelectric field on the basis of sparse geomagnetic observation data in China. Firstly, the model of equal Spherical Elementary Currents System (SECS) is used to represent ionospheric current. Then, the hybrid algorithm of SECS and Complex Image Method (CIM) is proposed to calculate the geoelectric field and the magnetic field due to geomagnetic disturbance. The method provided can be used to calculate the fields at any time, any place during magnetic storms. To test and validate the approach put forward, the observation geomagnetic data at Umq, KSH, GRM and JYG were applied, the induced fields in northwest area were calculated, and the errors between the measurement and calculation were analyzed as well. The results of geoelectric field are consistent with that of the plane wave method, which verifies the algorithm proposed. The results can be directly used to calculate the geomagnetically induced currents flowing in power system, which is of great significance in the hazards assessment of power systems.
Practical Analysis and Improvement of Klobuchar Model
Zhao Wei, Zhang Chengyi
2013, 33(6): 624-628. doi: 10.11728/cjss2013.06.624
Abstract(1377) PDF 482KB(1626)
Ionosphere delay error is an unneglectable error source in the propagation of radio signal. The GPS authorized users utilize dual-frequency observations of dual-frequency receivers to determine the ionosphere delay in real time, so the measured results have a high precision. Compared to authorized users, most general users use the ionosphere model to correct the delay error when they utilize single-frequency receivers. Relative to dual-frequency observations, the correction effect by ionosphere model is not ideal. In this paper, dual-frequency observations are used to verify the Klobuchar model which chosen by GPS broadcast ephemeris has a widespread application in single-frequency receivers. Ten days' data of WUHN Observation Station has been picked up to analyze Klobuchar model, and the obtained results were consistent with previous researching results. Also, a new improvement method is proposed based on previous analysis. Since the variability of ionosphere has a close relationship with the Sun's activity intensity, and the sunspot relative number is a symbol reflecting the Sun's activity intensity, the new improvement method is realized by means of sunspot relative number to modify Klobuchar model. This improved method has been proved with a large scale promotion in the correction effect through experimental data. Relative to original model, the correction rate greater than 50% has upgraded from about 60% to 85% above, and that greater than 80% upgraded from 10% to 40% above. In practical application, users of single-frequency receivers can refer to this improvement method to correct Klobuchar model.
Study of the Lower Thermospheric Neutral Wind at Chinese Arctic Yellow River Station During Auroral Substorms
Xiong Bo, Zhang Yange, Ai Yong, Zhang Hong, Liu Jue
2013, 33(6): 629-636. doi: 10.11728/cjss2013.06.629
Abstract(1322) PDF 5097KB(2112)
Auroral substorm is a basic energy input, coupling and dissipation process. Complex auroral substorm effects are not to be neglected for the thermospheric neutral wind effects, and has important significance on its in-depth study. A self-developed all-sky Fabry-Perot Interferometer (FPI) has been deployed by Chinese Arctic Yellow River Station (78.92°N, 11.93°E) at Ny-Alesund, Svalbard in November 2010, and formal observation has been carried out, which obtained FPI measured data for the first time in domestic. This paper briefly introduces the observations during winter in 2012. Two auroral substorm events on November 12-14, 2012 and December 9-11, 2012 were selected for data processing, and wind fields corresponded to 5 interference rings were calculated. The comparison and analysis between wind field and geomagnetic activity variations during the periods of auroral substorms indicated that the dramatic change of wind speed may be caused by a violent disturbance of geomagnetic activity. Contrastive analyses between auroral images by an all sky camera and FPI interference fringes corresponding line of sight wind field during November 13, 2012, 00:00UT-02:00UT and December 10, 2012, 05:00UT-07:30UT suggest that the enhanced direction is perpendicular to the aurora arc, and it weakens in the direction paralleled with the arc.
Effect of Solar Wind Speed on the Middle and High Atmosphere Circulation of Meteorological to Climatological Scale
Huang Jing, Zhou Limin, Xiao Ziniu, Chen Tao
2013, 33(6): 637-644. doi: 10.11728/cjss2013.06.637
Abstract(1047) PDF 1146KB(1644)
The relation between the solar wind speed and the winter northern hemisphere circulation, characterized as Arctic Oscillation (AO), was investigated with the superposed epoch analysis method and the correlation analysis method on the day-to-day and seasonal time scale. The results showed that on day-to-day time scale, the decease of solar wind speed associated with the dip of AO could be significantly detected, which implied that there exist the linkage chain from solar wind speed to the tropospheric circulation mediated by relativistic electron. This process could be explained by the correlation of "space particle-global circuit-cloud microphysics". On seasonal scale, the winter mean of solar wind speed in past 48 winters took significant correlation with the AO index. To understand the linkage between Sun and the climate, we should collect all the detailed physical environment information from Sun to low atmosphere in the future.
Research on Spaceborne FPI Detection of Lower Thermospheric Temperature
Liu Jue, Ai Yong, Zhang Yange, Hu Guoyuan, Xiong Bo, Chen Yao
2013, 33(6): 645-650. doi: 10.11728/cjss2013.06.645
Research on the atmosphere of 80~350km height is of great interest for understanding global aerodynamics and solar-terrestrial coupling. A Fabry-Perot Interferometer (FPI) is a multiple beam interferometer which makes it possible to obtain information on thermospheric airglow from its interference fringes. Recently, various ground-based instruments have been built in China for observing the upper atmosphere, but technology for the temperature inversion and spaceborne detection is still in the initial stage. Based on the convolution of system MTF and function of emission spectra, this paper discussed the detecting principle of inversion calculation on upper atmospheric wind and temperature. It also expatiated the method of spaceborne FPI detection, and simulated the interference pattern of spaceborne FPI. Finally, the feasibility of developing China's spaceborne detector for space environment detection is discussed, on the basis of development and strategic needs of space exploration.
Selection of Suitable Internal Control Genes in Microalgae Under Radiation Condition
Cai Wenkai, Hu Jinlu, Li Shuangshuang, Shan Ge, Wang Gaohong
2013, 33(6): 651-658. doi: 10.11728/cjss2013.06.651
As a major component of space radiation, ultraviolet radiation can extensively destruct terrestrial plants and aquatic. Real-time PCR technique has been widely used to detect the level of target mRNA expression when cell or tissues exposed to various types environmental stress. Choosing an appropriate internal control gene is important to accurately analyze the level of target gene transcription with real-time PCR technique. Therefore, our experiment tries to choose the most appropriate and stability reference gene from six traditional internal control genes, i.e., 18S rRNA, GAPDH, β-actin, β-tubulin, EF1-α and UBC in the Chlamydomonas reinhardtii under radiation conditions. The results showed that C. reinhardtii 18S rRNA gene expression is the most unstable through GeNorm analysis, but β-actin and GAPDH gene were finally selected as a pair of suitable internal control genes in expression analysis, with which more accurate experimental results can be obtained.
Experimental Study of Frequency Spectrum Characteristics in Spacecraft Dielectric Discharging
Quan Ronghui, Zhang Zhenlong, Han Jianwei
2013, 33(6): 659-663. doi: 10.11728/cjss2013.06.659
Abstract(954) PDF 979KB(1594)
Deep dielectric charging and discharging effect is one of the key factors threatening the spacecraft safety. Besides the dielectric and its grounding configuration, deep dielectric discharging is also affected by the electron environment in space. The space dielectrics such as FR4, Teflon and Polyimide were tested in a simulated space radiation environment on ground, and their discharging currents and electrical field pulses were recorded. By analyzing frequency spectrum characteristics of the discharging transients and the effect of dielectric temperature, electron energy and electron beam intensity, a peak frequency in discharging current was discovered. The result shows that the peak frequency varies with the dielectric thickness and electron energy, while no obvious change was observed at different beam intensities or temperatures.
Discussion on SFODB Application for Spacecraft Data Management
Qiu Aihua, Zhang Tao
2013, 33(6): 664-671. doi: 10.11728/cjss2013.06.664
Abstract(1004) PDF 1153KB(1742)
SFODB is used to solve the data exchange for payload of high data rates in spacecraft and transmit mass detector data, which is proposed by the United States Department of Defense. It is a high-speed aerospace data bus based on commercial Asynchronous Transfer Mode (ATM). In its physical layer, the fiber link connects many FBIU units and single CFBIU unit to compose a ring network. The distance between each node cannot exceed 100m, and the data rate ranges from 200Mbit·s-1 to 1Gbit·s-1. The data bus has very high real-time performance and reliability, and its network size as well as the performance is better than others. This paper introduces the characteristics and latest development status as well as the technical approach of SFODB up to now. It is suggested that an spacecraft internal data bus should be designed as the backbone data network architecture based on SFODB, such as for the satellites and other spacecrafts. The network can complete spacecraft internal reliable data transmission with hierarchical classification for payload. Finally, we give some guidance for research and application of SFODB in the future, some highly reliable design concepts about internal bus in spacecraft may refer SFODB.
Thermal Control Design and Simulation Calculation of the Alpha Particle X-ray Spectrometer
Zhang Jiayu, Wang Huanyu, Zhang Chengmo, Yang Jiawei, Liang Xiaohua, Gao Min, Wang Jinzhou, Cui Xingzhu, Peng Wenxi
2013, 33(6): 672-677. doi: 10.11728/cjss2013.06.672
Abstract(1203) PDF 1294KB(4491)
The APXS (Alpha Particle X-ray Spectrometer) is installed on the outside of the Lunar Rover, so that the lunar rocks and soil can be studied by the mobility of the Rover and flexibility of the robotic arm. Because of being exposed outside the rover, APXS will have great impact by the complex outer heat flux. In view of this, a reasonable thermal design is necessary for APXS to ensure that the APXS detector and electronic devices operate within the temperature range of its allowance. In this paper, the thermal control designs of APXS and the thermal simulation calculation results based on its thermal control designs are summarized. And the calculation results have been validated by corresponding thermal balance tests.
Research on Meridian Project Sounding Rocket Boom Deploying Technology
Yang Xuan, Yang Hua, Sun Jian, Zou Xiangrong, Ma Xin, Zhou Wei
2013, 33(6): 678-682. doi: 10.11728/cjss2013.06.678
Based on the needs of Meridian Project of sounding rockets' electronic and electric field probe, a sleeve-type of boom deployment mechanism was designed. Structure scheme design, mechanical simulation analysis, single mechanical property test, the whole rocket matching mechanical test as well as the flight test validation of both electronic boom and the electric field boom showed that the boom technical scheme is reasonable and feasible, and the boom overall configuration, layout design and structure design can meet the requirements of technical index for scientific exploration. According to the scientific exploration mission needs and space restrictions of the installation on the sounding rocket, a wide range of innovative design and development are carried out in the structure style, deployment and motion mode, locking and fixed mechanism of the boom deployment mechanism, as well as its installation on the rocket and release, etc.
Fuzzy Robust Sliding Mode Control and Flexible Vibration Active Suppression of Flexible-joint Space Robot Based on Flexibility Compensation
Xie Limin, Chen Li
2013, 33(6): 683-689. doi: 10.11728/cjss2013.06.683
Abstract(965) PDF 577KB(4599)
For free-floating flexible-joint space robot system with uncertain parameters, the dynamics modeling, motion controller design and flexible vibration active suppression are developed. Dynamic equations of the system are established by the system's linear and angular momentum conservation and Lagrange equation. In order to overcome the limitations of that the traditional singular perturbation method only applies to the system with weak joint flexibility, a joint flexibility compensator is designed to improve the flexible-joint's stiffness of space robot system equivalently. On the above basis, the system is decomposed into a slow subsystem and a fast subsystem by singular perturbation method, and the controllers of the subsystems are designed. The slow subsystem's fuzzy robust sliding mode controller can compensate the uncertain parameters, decrease the rotation angle transmission errors caused by the flexible-joint, and realize the asymptotic tracking of the system desired trajectory. The fast subsystem controller can suppress the flexible vibration caused by flexible-joint actively. The simulation experimental results prove the efficiency of the hybrid controller.