2011 Vol. 31, No. 1

Display Method:
Energy Budget in the Coupling Processes of the Solar Wind, Magnetosphere and Ionosphere
Xu Wenyao
2011, 31(1): 1-14. doi: 10.11728/cjss2011.01.001
Abstract(2408) PDF 843KB(1583)
On the basis of the principle of energy conservation, this paper reviews the aspects on energy input and dissipation in the coupling processes of the Solar wind, Magnetosphere and Ionosphere (SMI coupling). We focus on the following 9 principle issues: (1) solar wind energy input, (2) magnetosphere response to solar wind energy injection, (3) ring current dissipation, (4) Joule heating in the polar ionosphere, (5) auroral particle precipitation, (6) energy dissipation and storage in the magnetotail, and energy returning from the magnetosphere to solar wind, (7) energy accumulation and dissipation during quiet periods, (8) energy partitioning in different sinks, (9) the criterions and methods for assessing energy function.
Size and Shape of Magnetopause in the Noon-midnight Meridian Plane Based on the MHD Simulation
Liu Huilian, Huang Zhaohui
2011, 31(1): 15-19. doi: 10.11728/cjss2011.01.015
Abstract(2640) PDF 461KB(1288)
A quantitative model about the location and Shape of Magnetopause (MP) in the noon-midnight meridian plane is given by analyzing the computing data from three-dimensional global MHD simulation of the magnetosphere. Data processing results show the function which was presented by Ref.[3] based on the satellite observational data can also be used to describe MP in noon-midnight meridian plane. The location and shape of the MP in the noon-midnight meridian plane are more complicated than those in the equatorial plane. Although the MP in cusp region is ignored, the location and shape of MP need still be fitted by two different curves. The dynamic pressure of the solar wind (Dp) and the north-south component of the interplanetary magnetic field (IMF Bz) are two main factors determining the size and shape of MP. While for northward IMF Bz, r0 increases with increasing northward Bz; for southward IMF Bz, the standoff distance r0 decreases with increasing southward IMF Bz. On the whole, r0 increases when Bz turns northward from southward, and the influence of Bz on r0 becomes weaker. r0 is mainly affected by the dynamic pressure Dp, r0 decreases with Dp increasing. The other variable α, the level of tail flaring, increases with southward IMF increasing, which means the magnetopause flares more strongly and more magnetic flux transfers from the dayside to the nightside. The value of α rises slightly with Dp increasing, which implies that Dp also helps to some extent flux transfer from the dayside to the nightside.
Earthward Convective Bursty Flows in the Center Plasma Sheet
Zhang Lingqian, Wang Jiye, Liu Zhenxing, Shi Jiankui
2011, 31(1): 20-26. doi: 10.11728/cjss2011.01.020
Abstract(2383) PDF 500KB(1370)
With 4 s resolution data of FGM and HIA on Cluster/C1, the earthward Convective Bursty Flows (CBF) inside the region of -19 Re < x < -9 Re, -10 Re < y < 10 Re and -5 Re < z < 5 Re were statistically analyzed in the GSM coordinate. According to the statistical results, the CBF inside the Central Plasma Sheet (CPS) has distinctly ``braking'' inside 13~15 Re, and ``absence'' around 11.5 Re. The further detail analysis of the velocity of the CBF showed that the CBF move mainly toward the earth. The speed of the CBF has no clear decrease while moving earthward. In addition, the CBF have stronger perpendicular velocity inside 13 Re than outside 15 Re. This implied that the ``absence of BBF'' is not due to the deflection of the high-speed flows. The ``braking'' and ``absence'' of BBF may be closely related. The joint observations of TC-1 and Cluster satellites are important for understanding the transport process of the CBF in the CPS.
MF Radar in Kunming and Its Preliminary Observation Results
Zhao Lei, Chen Jinsong, Li Na, Zhao Zhenwei, Wu Jian
2011, 31(1): 27-33. doi: 10.11728/cjss2011.01.027
Abstract(2185) PDF 710KB(1138)
MF radar is an important instrument for measuring the wind field of the mesosphere and electron density of the lower ionosphere. The principle, configuration and working mode of a new MF radar in Kunming is presented firstly. Then, its observation data are preliminary analysed. The observation in January 2009 shows the certain fluctuation character of the horizontal wind with the largest zonal velocity of 80 m/s and meridional velocity of 40 m/s. The data in this month are studied by using Lomb-Scargle periodogram and harmonic fitting method. It indicates that the diurnal tide is the major perturbance component of the wind field in the height between 80~100 km. The amplitudes of the zonal and meridional tides change with height, and the phases propagating downward. It is also shown that the phase of the meridional tide is ahead of the zonal one. The comparison between the observed electron density on daytime and IRI2000 value indicates that both the variations versus height are agree well with each other, though sometimes the former is smaller.
Variability of the Atmosphere During the Sudden Stratospheric Warming Observed by the COSMIC Occultations
Xiao Cunying, Hu Xiong
2011, 31(1): 34-43. doi: 10.11728/cjss2011.01.034
Abstract(2631) PDF 920KB(1124)
Observations of COSMIC occultations which have high precision and high height-resolution from winter 2007 to spring 2008 are used to analyze the variability of the atmosphere between 10 and 60 km during the Sudden Stratospheric Warming (SSW), especially the features in the upper stratosphere and lower mesosphere. Results show that all of the temperature and wind fields and the residual circulation changed significantly during the SSW. According to the differences of the temperature before and during the major SSW, the latitude-altitude distributions of the temperature field could be divided into four parts by about 55ºN along latitude and by about 42\,km along altitude. At high latitudes, temperatures increased with a maximum warming of about 25 K in the lower stratosphere, while temperatures decreased with a maximum cooling of about 30 K in the upper stratosphere. At middle latitudes, temperatures cooled in the lower stratosphere while warming happened in the upper stratosphere by several K. During the SSW, both the zonal winds in the lower mesosphere and in the upper stratosphere changed nearly in the same way. Westerly winds became weaker and easterly winds strengthened in the north area of 45ºN, with a maximum increase up to 50\,m/s, while in the south area of 45ºN, westerly winds intensified and easterly winds weakened by a much smaller change of about 10\,m/s. From the last ten-day of January to the end of February, 2008, oscillations were observed in temperature and zonal wind fields with a period of about 12 days. The residual circulations reversed during the SSW, which suggested that directions of the transport of the atmospheric components also changed during the SSW.
Influence of Rays at Low Elevation Angles on the Ionospheric CT Imaging
Zhao Haisheng, Xu Zhengwen, Wu Jian
2011, 31(1): 44-50. doi: 10.11728/cjss2011.01.044
Abstract(2042) PDF 724KB(986)
The ionospheric CT imaging is a limited angle tomography problem. The lack of horizontal rays severely degrades the vertical resolution of the ionospheric CT reconstruction results. Many people intuitively thought that the adverse effects due to the lack of horizontal rays can be compensated by including rays at low elevation angles. However, it is shown by both theoretical analysis and numerical simulation that the influence of rays at low elevation angles on the CT results is too small to mitigate the degradation in vertical resolution due to the lack of horizontal rays. The numerical simulations show that electron density images reconstructed are almost no changes whether consider rays at low elevation angles or not. But, when disregards 680 rays at low elevation angles and 680 rays at high elevation angles at same time, the change is very large. The CT imaging result consists with the model after taking out 680 rays at low elevation angles. But The CT imaging result changes largely comparing with the model and the small-scale structures cannot be discriminated when taking out 680 rays at high elevation angles.
CPU/GPU-based Parallel Models of Coronal Polarization Brightness Calculation
Jiang Wenqian, Zhong Dingkun, Xie Zhangpeng, Wang Qun, Feng Xueshang
2011, 31(1): 51-56. doi: 10.11728/cjss2011.01.051
Abstract(2473) PDF 545KB(953)
Applied Research, Chinese Academy of Sciences, Beijing 100190)
The three-dimensional numerical Magnetohydrodynamics (MHD) simulation is one of the methods to study the corona and solar wind. Comparison of the Polarization Brightness (PB) in the low corona between simulation results and observation is important to validate the MHD models. Because of the massive data and the complexity of the PB model, the computation will take too much time on single CPU (or core), and can not visualize the PB in nearly real time, so that it affects the validation efficiency of numerical modeling. A new parallelized model based on CPU/GPU with Compute Unified Device Architecture (CUDA) to convert MHD simulation density to PB is presented in this paper. Aiming at the most time-consuming part of the serial PB model, it modifies the model from serial process to parallel process based on CUDA to improve its computation efficiency. It shows that the new model can speed up 31.86 times than the serial model based on CPU, and is able to compare the simulation with observation in nearly real time.
Thermodynamics of Flashing/Freezing Process of a Droplet in Vacuum
Zhao Kaixuan, Zhao Jianfu, Chen Shuling, Du Wangfang
2011, 31(1): 57-62. doi: 10.11728/cjss2011.01.057
Abstract(2384) PDF 536KB(1488)
To reveal the mechanism of the flashing/freezing process of a liquid droplet in vacuum, a new model of heat and mass transfer in the flashing/freezing process was established using a quasi-equilibrium process of mass and heat transfer. Based on the numerical results of the variation of droplet's size and temperature, influences of four factors, namely ambient pressure, ambient temperature, initial radius and temperature of the droplet, on the variation of pre-cooling time in the flashing sub-process, freezing time in the fast freezing sub-process and the final temperature of the process were analyzed in detail. Compared with the experimental data, the present model can predict the basic features of the process with a good reliability. The ambient pressure is the dominating factor determining the major features and the final temperature of the process. The initial temperature affects the flashing rate, while initial radius influences the pre-cooling time. The influence of the ambient temperature is too slight that can be neglectable.
Application of Magnetic Levitation of Diamagnetic Materials for Space Biology and Biotechnology
Cao Jianping, Yin Dachuan, Qian Airong, Tian Zongcheng, XU Huiyun, Huang Yongping, Shang Peng
2011, 31(1): 63-72. doi: 10.11728/cjss2011.01.063
Abstract(2915) PDF 752KB(1462)
Weightlessness is one of the important physical characteristics of space environment. For several decades, weightless environment in space has been used for investigation and exploration in many scientific fields. Because of shortage and limit of experiments in real space environment, many kinds of ground-based simulated techniques and methods inspired by space experimental environments were developed for simulating the weightlessness of space environment and the effects of weightlessness. However, these techniques and methods have limitations not only in principle, but also in application for space biology and biotechnology. In this paper, we introduced a new technique for simulating weightlessness, magnetic levitation of diamagnetic materials produced by large gradient high magnetic field, and summarized the research progress by using this technique in crystal growth of proteins, molecular cell biology and integrated biology.
Altered Gravity Induced Ca2+ Signal in Plant Cells
Xiao Yuan, , Wang Gaohong
2011, 31(1): 73-79. doi: 10.11728/cjss2011.01.073
Abstract(2682) PDF 683KB(1004)
Altered gravity (microgravity and hypergravity) could affect many aspects of plants, such as growth, development, metabolism, ultrastructure, gene and protein expression. Ca2+ might play a role as a signal molecular in such graviresponses of plant. We supposed that the consequence of events occurring in plant cells under altered gravity were in the following order: gravisensing---changes in the cytoplasmic membrane surface tension---alterations in the physicochemical properties of the membrane---changes in membrane permeability, ion transport, membrane-bound enzyme activity etc--- Ca2+ signaling---metabolism rearrangements---physiological responses. Under altered gravity, the intracellular Ca2+ balance was redistributed and the increased cytosolic Ca2+ concentration was the key step of transforming altered gravity stimulation into intracellular Ca2+ signal. Ca2+ influx into the cytosol was via activation of Ca2+ selective ion channels and inhibition of Ca2+-ATPases. Following the increased cytosolic Ca2+ concentration, altered gravity induced a series of biological effects by regulating enzyme activity, with involvement of regulatory Ca2+ messenger system. This paper summarized the influences of altered gravity on plant intracellular Ca2+ balance and discussed the possible pathways of Ca2+ influx/efflux and Ca2+ signaling in plant cell biochemical regulation to altered gravity.
Electromagnetic Levitation Force and Loop Structure
Ye Jingwei, Ding Wenyao, Sun Zhibin, Huang Huang, Zhao Qing, Zhai Guangjie
2011, 31(1): 80-86. doi: 10.11728/cjss2011.01.080
Abstract(2394) PDF 639KB(1275)
Electromagnetic Levitation (EML) is a kind of technology for containerless processing of material. It has a lot of advantages, such as no contamination, processing materials with higher melting point, stronger erodibility and easy concreting nucleus. The important levitation is to produce big levitating force against gravity on the ground, and to compensate the remaining gravity in space. In this paper, the distribution of levitating force produced by loops is calculated. A stable potential well is also studied and produced to capture the sample. The calculation is mainly focused on the relation between the distribution of levitating force and the structure of loops, such as the number of turns, the angle of wimble, the radius of loop, the space and screw-pitch between loops. A series of curves representing the properties of different structures and the theoretical support for actual loop designs have finely been tend.
Integrated Control for Crystal Growth Furnace in Space
Yu Qiang, Yu Haofeng, Liu Wei
2011, 31(1): 87-92. doi: 10.11728/cjss2011.01.087
Abstract(2057) PDF 582KB(1332)
Crystal growth furnace in space is a complex system which has the characteristics of pure-delay, strong-coupling and nonlinearity. To meet the high precision temperature control of the crystal growth, a new integrated control software for crystal growth furnace in space is presented. The software has the modules of system identification, parameter tuning, computer-aided simulation and real-time system control. The correlation coefficient and the least squares method are used to accomplish the identification of the process model, the parameters of the controller are tuned by Hooke-Jeeves mode searching method, PID and Feed-forward algorithm are used to control the multi-zone furnace together. To simulate the process of controlling, it can adjust the parameters of the controller. After attaining a result of meeting requirement, it uses the parameters of the controller getting in simulation to control the furnace in real time on line. Through the integrated control software, we achieve batter results, when the three zones temperatures rise to 700ºC, the stabilities of the three zones are all less than ± 0.3ºC. The strong-coupling among these three zones are suppressed clearly. The basic principle, powerful functionality, attractive features are discussed in details. The application of this software shows its effectiveness.
Study on the Effects of Protons to Spacecraft Internal Charging With Monte Carlo Method
Tian Tian, , Jiao Weixin, Chen Xu, Li Long, Wan Yinghu
2011, 31(1): 93-99. doi: 10.11728/cjss2011.01.093
Abstract(2030) PDF 568KB(1241)
In this paper, the basic mechanism of spacecraft internal charging was introduced, and proton's effect on internal charging was mainly studied. Monte Carlo method is used to simulate the transporting process of proton in dielectric and the internal charging results in certain flux environment for the case of simple plane dielectric were calculated. Results indicate that the maximum electric field is correlated with the energy of the inject protons, and the electric field reached its maximum value under certain energy; that for the same number of injected particles and the same material parameters, the maximum electric field produced by proton is much higher than that produced by electron. Proton and electron data on 26th July, 2004, the time just before TC-2 satellite's attitude control system becomes invalid were chosen to calculate the internal maximum electric field produced by protons and electrons. The results reveal that the maximum electric field produced by protons is 2~4 magnitudes smaller than that produced by electrons, mainly due to proton's much smaller flux than that of electron.
Applications of the Visualization of Lunar Surface Based on Chang'E-1 Observations
Zou Xiaoduan, , Liu Jianjun
2011, 31(1): 100-105. doi: 10.11728/cjss2011.01.100
Abstract(2690) PDF 774KB(1084)
The Chang'E-1 is the first Chinese lunar explorer. One of the major objectives of the mission is to obtain photographic and topographic data of the moon. Based on these data, applications of the visualization of lunar surface are discussed in this paper. The methods to develop lunar topographic map from Chinese Chang'E-1 lunar data are introduced. The methods include color-coded shaded relief mapping, 3D modeling and data fusion. The software for shaded relief mapping is presented and briefly compared. And the construction of 3D topographic model is discussed. Then, data fusion theories are summarized. And procedures of image fusion based on HIS transformation are applied in lunar visualization. The examples using lunar data obtained by Chang'E-1 were shown in each section of the methods explanation. In the end, the future of lunar visualization is anticipated.
Research on the Reliability of FPGA Configuration in Space-based Systems
Wang Wenhua, Han Shuangli, Zhang Yu, Li Guoning, Li Xine, Ren Jianyue
2011, 31(1): 106-111. doi: 10.11728/cjss2011.01.106
Abstract(2384) PDF 704KB(1738)
Designers of space-based systems face unique challenges to insure each unit against failure. FPGA are used gradually in the aerospace field since it is invented with abundant I/O pins and flexible design margin. Many manufactures have been improving those space-qualified FPGA devices to adapt the aerospace high-radiation environments. FPGA devices based on SRAMs have to load configuration data from external PROMs on power-up before the logic is activated. However, not each batch or each device can be configured successfully with zero-failure. This paper explores every possible factor such as environment temperature, signal integrality, configuration rate and so on. Aiming at Xilinx FPGA devices, this paper provides a series of safeguard solutions for higher reliability of configuration. It has significant reference value in aerospace application fields for its feasibility and reliability.
Mechanical Characteristic Analysis of the Magnetometer Structure Component for the Space Exploration
Zhuang Hongchao, Wang Jindong, Wang Ning, Shi Rong, Li Yan
2011, 31(1): 112-117. doi: 10.11728/cjss2011.01.112
Abstract(1805) PDF 695KB(898)
Finite element technique is utilized to analyze payload of the detector, which is the high precision magnetometer structure component. When the magnetometer structure component bears impact load of 40 g in the blastoff process and simultaneously bears extreme temperature ranging from -180ºC to 75ºC, the maximum stress and displacement are respectively obtained in the directions of x, y and z. Moreover, due to the deformed magnetometer structure component, deflective angles of three probes are also obtained in the three directions. Finally, the sweep experiment is utilized to analyze spectrum characteristics of the magnetometer structure component, and the objective of experimental date has been obtained. It verifies the dynamic characteristics of the magnetometer structure component and provides technical support for the space-borne magnetometer designing.
Visibility Research on Downward Antenna of Spaceborne GPS-R System
Zhang Xiaokun, Yuan Hong
2011, 31(1): 118-124. doi: 10.11728/cjss2011.01.118
Abstract(1946) PDF 632KB(1003)
The influences on visibility of specular points are investigated from several properties of the spaceborne GPS-R system downward antenna in the oceanographic remote sensing, including beam center pointing, beam geometry and beam scanning manners. In particular, we firstly defined a subastral plane which has a one-to-one mapping relationship with points on the Earth in beam zone coverage; then presented a scheme to figure out beam zone coverage in this plane, and then analyzed the influences on visibility from beam center pointing, beam geometry and beam scanning manners. A configuration of beam geometry and beam scanning manners are proposed, in which the direction with larger half power beam width of the downward antenna's two main directions in the lobe pattern is vertical to the LEO satellite velocity direction in subastral plane. These research conclusions have been verified by simulation in the potential GPS-R system in the oceanographic remote sensing, based on the orbit of a LEO satellite which can be used in the future.