2014 Vol. 34, No. 3

Display Method:
Comparison between Diviner Data and CELMS Data
Ran Zhen, Wang Zhenzhan, Li Yun
2014, 34(3): 249-261. doi: 10.11728/cjss2014.03.249
Abstract(1068) PDF 3248KB(1943)
With a selected spot (45.1°-45.5°N, 33.1°-33.5° W) in Sinus Iridum, the measurements by Chang'E Lunar Microwave Sounder (CELMS) at five different lunar local time are analyzed. Then the lunar microwave brightness temperatures at four different frequencies of CELMS are simulated based on the microwave radiative transfer model. Grounded on the analyses for CELMS2 measurement as well as the simulated brightness temperatures in matched longitude, latitude and solar elevation angle, it is suggested that these two kinds of brightness temperature have a high correlation coefficient which can tend to 96%. Therefore, the stability of measurements of CELMS2 is verified.
Prediction of Solar Proton Events and Radio Type I Noise Stormorm
XIA Zhiguo, GAO Guannan, WANG Min, LIN Jun
2014, 34(3): 262-268. doi: 10.11728/cjss2014.03.262
Abstract(1142) PDF 1697KB(1117)
The Sun is a very active astronomical object. Its great exploding energy can severely affect the Earth's space environment. Since a single high energy proton is sufficient to damage the normal operation of microelectronic devices in a spacecraft, the solar proton events' forecast is very important in space weather forecast. The prediction model of previous ones needs improvement in some aspects of the choice of prediction parameters. Metric Type I burst is closely related to magnetic reconnection and coronal heating, and therefore can be used as one of the forecast parameters. The paper provides some detailed data of two typical solar eruption events, which have illustrated the correlation between Type I noise storm and proton events, CME. Yunnan Observatory has built a solar radio telescope of 11m diameter, which frequency ranges from 70MHz to 700MHz, and the resolution can reach 200kHz. Its time resolution is programmable between 20ms and 80ms, and the dynamic range can reach nearly 72dB. The radio telescope is located by Fuxian lake about 60km away from Kunming. It can not only observe Type Ⅱ-Ⅳ bursts, but also observe Type I noise, hence plays an important role in prediction of space weather.
Electromagnetic Energy Transfer across the Magnetopause
JING Hao, LÜ Jianyong, JIANG Yong, WANG Ming, HU Huiping, LIU Ziqian
2014, 34(3): 269-277. doi: 10.11728/cjss2014.03.269
A three-dimensional adaptive magnetohydrodynamic (MHD) model is used to examine the electromagnetic energy flow from the solar wind to the magnetosphere. The magnetopause is determined by finding approximately the inner edge of the void encompassed by the solar wind stream lines, and the magnetopause is divided into nightside and dayside part by polar cusp region. This study found that the magnetopause energy transfer has close relations with solar wind conditions. The magnetopause area also effects energy transfer. For northward IMF, most of the electromagnetic energy flux inflow occurs near the polar cusps on magnetopause; for southward IMF the largest electromagnetic energy input into the magnetosphere occurs at the tail lobe behind the cusps. Under southward IMF conditions, more electromagnetic energy input can be identified as increasing solar wind density while it does not enhance as much for northward IMF. Our results suggest that the mechanisms proposed to electromagnetic energy transfer are mainly due to reconnection. If the electromagnetic energy coupling between the solar wind and the magnetosphere can be interpreted as a proxy for the reconnection efficiency, the efficiency during northward IMF is about 10%~30% of that for southward IMF under the solar wind conditions we considered.
Test of the Dynamical Non-stationarity in Geomagnetic Variation Field Based on Improved Space Time-Index Method
LU Shikun, LI Xihai, NIU Chao
2014, 34(3): 278-286. doi: 10.11728/cjss2014.03.278
Abstract(914) PDF 752KB(1027)
Space Time-Index (STI) plots is a graphical method used for testing dynamical non-stationary in general time series. In this paper, the non-stationary characteristics of the z components of geomagnetic field variations with the improved Space Time-Index (STI) plots method were analyzed, and data under different K indexes, different Lloyd seasons, as well as day and night are used. The result shows that the improved space time-index plots method can effectively test whether dynamical non-stationarity exists in geomagnetic variation field, and there is dynamical non-stationarity in z component. On the other hand, the analysis of the z component from different K-indexes introduces that, with the increase of K-index, the phase space distributions of z component become increasingly more uneven and the time evolution features become more complex. Research on geomagnetic field variation from different Lloyd seasons presents that the shapes of the STI plots of z component from different Lloyd seasons are similar. However, as the decrease of the Sun-Earth distance, the complexity of the time evolution of z component becomes heightened, showing some seasonal variations. And the conclusion obtained from the study of diurnal variation of geomagnetic field is that, fluctuation of the STI plots of z component in night time is more severe than that in daytime, and the diurnal variation of z component is obvious.
A Simulation of the Mid- and Low-latitude Ionospheric Electric Fields
YU Tao, MAO Tian, XIA Chunliang, WAN Weixing
2014, 34(3): 287-295. doi: 10.11728/cjss2014.03.287
Abstract(828) PDF 615KB(1924)
A theoretical model of ionospheric electric fields at mid- and low-latitudes is developed. In the geomagnetic dipolar coordinate system, the ionospheric dynamo equations were solved, and the ionospheric electric potential and electric field were derived respectively. Major parameters for the model inputs, such as the neutral winds, the densities and temperatures of electron, ions and neutrals, are obtained from empirical models. The global ionospheric electrical potential and field at mid- and low-latitudes derived from our model are largely in agreement with the results presented by other authors and the empirical model. Using our model, it is found that the diurnal component of the HWM93 wind mainly contributed to the formation of the vertical electric field, while the semidiurnal component mainly contributed to the zonal electric field. Finally, by adjustment of the input F region winds and conductivities, most discrepancies between our model and the empirical one can be eliminated, and it is proved that the F region dynamo is the most significant contribution to the electric fields.
Application of Atmospheric Disturbances Monitor on Lithosphere-atmosphere-ionosphere Coupling
Hu Xiaoyan, Zhang Donghe, Hao Yongqiang, Xiao Zuo
2014, 34(3): 296-303. doi: 10.11728/cjss2014.03.296
Gravity waves and infrasonic waves play important roles in the coupling of lithosphere, atmosphere and ionosphere. This paper analyzes the observational data of Atmospheric Disturbances Monitors, which are developed by Institute of Space Physics and Applied Technology, Peking University. The morphological features and spectral structures of the observed gravity waves and infrasonic waves are presented, then their temporal distribution characteristics are summarized. We also have done some case studies about thunderstorms and earthquakes. The disturbances of atmosphere recorded by Atmospheric Disturbances Monitor and the similar observations of ionospheric disturbances during these events are presented. These results reveal that Atmospheric Disturbances Monitor could record the week disturbance of the surface atmosphere, proving which a useful tool for study of Lithosphere-Atmosphere-Ionosphere coupling.
Analysis of Surface Wave Plasma Drag Reduction Properties in Near Space
Cai Honghua, Nie Wansheng, Feng Songjiang
2014, 34(3): 304-312. doi: 10.11728/cjss2014.03.304
In order to investigate the drag reduction effect of surface wave plasma in near space, this paper analyzes the surface wave plasma flow control mechanism based on basic characteristics of the fluid control macro model, simulates its flow field in the 0 degree angle of attack based on the airship model. The drag reduction effect of different actuator control program is compared, and the plasma flow control effect on the airship tail is studied. Results show that the surface wave plasma can increase the airship lift and reduce its flight resistance. The airship lift can be increased through the unilateral control scheme, while the symmetrical control scheme is invalid for the airship lift because of the airship force balance in the vertical direction. The maximum drag reduction effect of unilateral control scheme is about 7 percent, and the symmetrical control scheme is better than unilateral one with its maximum drag reduction effect up to about 32 percent. The surface wave plasma has good elimination and inhibition of flow separation in the airship tail.
Global 4D Trajectory Optimization Design for Lunar Vertical Soft Landing
Huang Guoqiang
2014, 34(3): 313-318. doi: 10.11728/cjss2014.03.313
Abstract(755) PDF 620KB(1247)
A combinatorial algorithm, including dynamic programming and conjugate gradient, was proposed for 4D trajectory global optimization of the lunar probe vertical soft landing. By employing the suboptimum control variable calculated from dynamic programming as the initial control variable of conjugate gradient algorithm, the more precise optimum control variable and flight trajectories were obtained. The lunar probe vertical soft landing trajectory consists of two segments, i.e., the brake and landing segments. The performance index is to minimize fuel consumption of the lunar detector. The 4D trajectory of lunar vertical soft landing is optimized by this combinatorial optimization algorithm. Simulation results showed good accuracy, rapid convergence, and robustness with initial values for this combinatorial algorithm, which promise it to on-line generate a feasible vertical soft landing trajectory on the onboard computer. Meanwhile, the combinatorial algorithm could be extended to other two-point boundary value problems of terminal time uncontrolled type.
Fast Fitting Algorithm of Non-cooperative Space Object’s TLE Parameters
Liu Guangming, Zhang Zhi, Che Wanfang
2014, 34(3): 319-326. doi: 10.11728/cjss2014.03.319
Due to the singularity existence in the iterative approximation procedure, a new Two-Line Elements (TLE) sampling fitting method is put forward according to the non-singular transformation of orbital elements. To improve the data-processing efficiency of space-based observation platform to the non-cooperative space target, the TLE fitting algorithm introduces the adaptive forgetting factor recursive least-squares algorithm. Numerical simulations indicate that the method can enhance the iterative rapidity of convergence and the accuracy of forecasting orbit, especially for near-Earth space objects. The fitting method can be applied to the tracking system of space-based observation platform to the near-Earth orbit target.
Vibro-acoustic Response Analysis of Aircraft Structure Based on Hybrid FE-SEA and Experimental Verification
Zhang Guojun, Yan Yunju, Li Pengbo
2014, 34(3): 327-331. doi: 10.11728/cjss2014.03.327
For structural vibro-acoustic coupling methods, a general accepted view is that the Finite Element (FE) method is suitable in low-frequency band, and Statistical Energy Analysis (SEA) methods is more appropriate in high-frequency band. However, there are no suitable methods for the medium-frequency band. Moreover, in different engineering fields, the division of high- medium-and low-frequency band is also different. The vibro-acoustic coupling dynamics of hybrid FE-SEA model of the hypersonic aircraft X-43A is established based on FE-SEA theory. In order to study the performance and property of vibration caused by aerodynamic noise, the external noise field is assumed as known. The noise transmission and structure coupling vibration are analyzed by hybrid FE-SEA method. Structural vibration response and the noise field response of the aircraft model are obtained. Finally, reliability of the theory and numerical calculation is verified through noise experiments.
Chang’E-3 Lunar Rover’s Scientific Payloads
Dai Shuwu, Wu Ji, Sun Huixian, Zhang Baoming, Yang Jianfeng, Fang Guangyou, Wang Jianyu, Wang Huanyu, An Junshe
2014, 34(3): 332-340. doi: 10.11728/cjss2014.03.332
Abstract(1206) PDF 1987KB(2053)
Four scientific instruments are selected as the payloads for Chinese Chang'E-3 Lunar rover, including panoramic cameras, lunar radar, IR acousto-optic spectrometer, X-ray spectrometer. Panoramic cameras are to acquire the stereo optical image of lunar surface topography around the lunar rover. Lunar radar explores the lunar regolith thickness and structure. IR acousto-optic spectrometer obtains the IR spectrum and image of lunar surface, which can be used to analyze the lunar surface's mineral composition and distribution. X-ray spectrometer analyzes the content of the lunar surface rock to get the rock elements composition. In this paper, Chang'E-3 Lunar rover's scientific exploration objectives, the scientific payload's components and system design are mainly introduced. Each payload's design and main technical index are also described in detail.
Technical Configuration and Simulation of NAIS-H for the MIT Mission
LU Li, S McKenna-Lawlor, J Balaz, SHI Jiankui, YANG Chuibai, LUO Jing
2014, 34(3): 341-351. doi: 10.11728/cjss2014.03.341
Energetic Neutral Atoms (ENA) are generated within the Earth's magnetosphere through charge exchange between magnetically trapped energetic ions and cool neutral gasses. An ENA imager can potentially record the arrival directions and energies of magnetospheric ENAs, as well as provide (indirectly) global images of the spatial and energy distributions of their parent ion populations. Preliminary technical configuration and simulation of the Neutral Atom Imaging System for high energy neutral atoms (NAIS-H) designed for the Chinese Magnetospheric-Ionospheric-Thermospheric (MIT) mission are described. In inherited the design concept of NUADU and focus on the main scientific objective of MIT and the orbit, a preliminary technical overview of this instrument is provided. The simulations under a dipolar magnetic field model show that the instrument has the capability to monitor global dynamic processes with high temporal and spatial resolution.
Multiband Microwave Radiometer Design and Development for HY-2 Oceanic Calibration/Validation Site
Liu Jingyi, Wang Zhenzhan, Zhang Yu, Zheng Wei, Li Bin
2014, 34(3): 352-359. doi: 10.11728/cjss2014.03.352
Abstract(1148) PDF 1991KB(1170)
Oceanic Multiband Microwave Radiometer (OMMR) with five frequencies and ten channels is designed for the calibration and validation of HY-2 satellite's scanning microwave radiometer. The development of this remote sensor is challenged with harsh working environment as well as long-term stable continuous 360° observation. In this paper, it is focused on the radiometer's system constitution, design and implementation of technical indicators. OMMR system includes eight functional units, i.e., antenna, receiver, scanner, calibration unit, temperature measurement, data sample and system control unit, power source and structure. The process of system indicators test and calibration is described. Testing results showed that the radiometer can meet the design requirements.
Study of Surface Charging and Discharging Effects on Solar Array Drive Assembly
Li Rui, Liu Jikui, Xu Yuemin, Wang Youping, Liu Lei, Chang Xiao, Wu Fengshi, Sun Hailong
2014, 34(3): 360-366. doi: 10.11728/cjss2014.03.360
Abstract(996) PDF 802KB(1271)
The spacecraft surface charging and discharging resulting from the space plasma environment is one of the main causes of spacecraft abnormity and malfunction. Solar Array Drive Assembly (SADA) is a crucial component of the electrical transfer sub-assembly of the modern long life and large power satellite, which is used to rotate the solar array to follow sunlight for maximum energy acquisition, as well as transfer power and signals from the solar array to satellite. SADA is installed at the interface of spacecraft body and outer space, so it is directly exposed to the space plasma environment and prone to the adverse effects of charging and discharging. When SADA malfunctions, the satellite will lose energy and results a failure of the whole satellite. In order to test the influence of surface charging and discharging by the space plasma environment on SADA, especially its power transfer reliability and safety, a plasma environment simulation device simulating the plasma environment in the GEO orbit, was utilized to conduct experimental test on a SADA. The SADAs utilizing different dielectrics demonstrated similar effects in the space plasma environment. The test result also demonstrated that the surface charging and discharging would not influence the normal functionality of SADA with proper design. The test result will serve as a good foundation for the design of future space mechanisms like SADA for higher reliability and safety.
Impact Dynamics of Flexible Space Manipulator Capturing a Satellite, Stabilization Control and Flexible Vibration Linear Quadratic Optimal Suppression
Dong Qiuhuang, Chen Li
2014, 34(3): 367-376. doi: 10.11728/cjss2014.03.367
Abstract(878) PDF 685KB(3749)
The impact dynamics of space manipulator system capturing a satellite, and control of post-impact unstable system were discussed. The dynamics model of space manipulator system was derived by the second Lagrange equation. At the impact moment when the space manipulator capturing a satellite, the impact effect for the space manipulator was calculated by momentum impulse method. For stabilizing the post-impact unstable space manipulator and satellite combination system, the linear feedback and linear quadratic optimal composite control algorithm was proposed for the space manipulator stabilization control and flexible link vibration suppression, and there was no need for the position control of the free-floating base under the proposed control algorithm employed, which would save the fuel consumption of free-floating base thruster. Finally, numerical examples are proposed to simulate the impact effect for space manipulator motion state which is caused by the impact, and the effectiveness of above control algorithm is verified.