2022 Vol. 42, No. 1

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Chang’E-4 Energetic Neutral Atom Observation Reveals New Features about the Solar Wind–Moon Interaction
XIE Lianghai, ZHANG Aibing, LI Lei, WANG Huizi, SHI Quanqi, ZHANG Jiang, WANG Wenjing, WEISER Martin, ZHANG Yiteng, KONG Linggao, FENG Yongyong, ZHOU Bin, WANG Jindong
2022, 42(1): 11-24. doi: 10.11728/cjss2022.01.20220113
Different from the Earth, the solar wind can directly impact the lunar surface, and partly be scattered as Energetic Neutral Atoms (ENAs). However, the lunar magnetic crustal fields in some regions, called magnetic anomalies, can deflect the solar wind to form a mini-magnetosphere, shielding the surface. All previous understandings about these processes are obtained from orbit, and the truth on the lunar surface is still unknown. The Advanced Small Analyzer for Neutrals (ASAN) onboard Chang’E-4 mission can detect the reflected Energetic Neutral Atoms (ENAs) from the lunar surface, which will provide new perspectives to study the solar wind interaction with the Moon. Here is a review on the recent works with the ENA data from ASAN, focusing on introducing some new discoveries by ASAN, such as a higher ENA reflection ratio, more ENAs gathered at lower energies, and some heavier ENAs other than the H ENA. Compare with the upstream solar wind data, it is found that the ENAs in the energy range of 105~523 eV are closely related with the solar wind. Moreover, the ENA fluxes downstream from the magnetic anomalies are generally smaller. Combined with the global Hall MHD simulation, reduction in the ENA flux is confirmed to be caused by a mini-magnetosphere. Meanwhile, it is found the formation of the mini-magnetosphere is determined by the solar wind dynamic pressure and the ion inertia length, and the mini-magnetosphere brings a deceleration to the solar wind, by a differential electrostatic potential of 50~260 V.
Three-dimensional Numerical Simulation of Coronal Solar Wind
LIU Chang, SHEN Fang, LIU Yousheng
2022, 42(1): 25-33. doi: 10.11728/cjss2022.01.201127102
The Coronal Interplanetary-Total Variation Diminishing (COIN-TVD) magnetohydrodynamic (MHD) model developed in recent years that can effectively realize the coronal-interplanetary three-dimensional (3D) solar wind simulation. In this paper, the 3D coronal solar wind is studied by using this model. In order to simulate the heating and acceleration of solar wind in coronal region, the volume heating term in the model is improved. For MHD simulations, one of the key problems is to remove the magnetic field divergence error. Then, the influence of different methods to reduce the magnetic field divergence error on the coronal solar wind structure is discussed. The background solar wind of CR2199 is simulated by the diffusive method, Powell method, Diffusive and Powell method. The simulation results are consistent with the features of the coronal solar wind. The Diffusive and Powell method can control the relative magnetic field divergence error at the order of 10–9.
Quantitative Characterization of Photospheric Magnetic Field in Solar Active Regions
YANG Xiaohua, WANG Qixi, XIA Zhongfei, BAO Yun, PENG Dailiang, TIAN Tian, XU Long
2022, 42(1): 34-43. doi: 10.11728/cjss2022.01.200826076
In order to resolve the quantitative technique of photospheric magnetic field in solar active regions, all SOHO Michelson Doppler Interferometer (MDI) magnetograms from 1996 to 2011 have been used, and all solar active regions located within 45° solar surface angle have been segmented. The projection distortion of magnetogram area have been studied, then the consine factors for area correction have been established, and solar active regions area have been corrected. Based on the photospheric parameters quantified by Ref. [18–20], the index system has been built and improved, and it has been used to quantity characterization of magnetic field. The quantitative result has been analyzed by the Principal Component Analysis (PCA), and magnetic field of active region10486 erupted X17.2 flare has been analyzed. The results show that R, LPS, Lsg and $\phi $PSL can explain the change of magnetic field structure in active region, and $\phi $uns, $\phi $, $\phi $tot, and $\phi $mean can explain the change of magnetic flux in active region. $\phi $PSL is the new characteristic parameters in this paper. The above parameters can monitor the changes of magnetic field structure and magnetic flux in the active region effectively before and after the flare eruption; the quantitative results could be used as the input of flare, proton event monitoring and flare prediction model, and provided technical support for the monitoring and early warning of solar flare activity.
Response of Substorm Onset Location and Expansion Phase Duration to Interplanetary Magnetic Field Bz
REN Ganming, CAO Jinbin, MA Yuduan
2022, 42(1): 44-50. doi: 10.11728/cjss2022.01.201112099
A magnetospheric substorm is a significant process in solar wind-magnetosphere- ionosphere coupling. Substorm onset locations have a great dependence of solar wind parameters. Based on 4193 auroral breakup events identified by Frey et al. from about 5 years IMAGE FUV data, we statistically study the distribution of substorm onset locations and substorm expansion duration time under different Interplanetary Magnetic Field (IMF) conditions in southern and northern hemispheres. It is found that the occurrence rate of a substorm is relatively bigger under southward IMF than northward IMF. The maximum value of substorm AE index is above 600 nT under southward IMF, and increases with the evolution of southward IMF lasting time. While the maximum value of substorm AE index is beneath 500 nT under northward IMF, and decreases with the evolution of northward IMF lasting time. The substorm onset magnetic latitude is around 65°-70°. With the lasting time of northward/southward IMF exceeding 80 minutes, the substorm onset magnetic latitude in the northern hemisphere lower with the evolution of IMF lasting time. The substorm onset is around 22:15-23:15 MLT. It’s irregular under different IMF lasting time. The average expansion time of substorm is about 10 minutes larger under northward IMF than southward IMF. It indicates that the speed of substorm energy release and dissipation is faster under southward IMF with intense substorms.
Statistical Relationships between Ionospheric Upflows and Various Parameters during Geomagnetic Storms
WANG Rukun, ZHAO Kai, FENG Dandan, WANG Zihui, TANG Muxian, XIONG Yating, FENG Ling
2022, 42(1): 51-64. doi: 10.11728/cjss2022.01.201116101
A collection of data from 149 orbits by the Fast Auroral SnapshoT (FAST) mission during 34 geomagnetic storms from 1997 to 2006 is used to analyze the energy flux of upflowing ions as a function of storm phases, and analyze the relationships between the flux and the parameters, including Sym-H index, Kp index, and the Poynting flux to construct empirical models. Results show that, in the main phase of the storm, the energy flux exceeds 108 eV·cm–2·s–1·sr–1·eV –1, and in the initial and recovery phases, the energy flux can exceed 107 eV·cm–2·s–1·sr–1·eV –1. The averaged energy flux in the main phase is higher than that in the initial and recovery phases. In the initial phase, the flux is significantly positively correlated to Sym-H, Kp and the Poynting flux. The correlation coefficients are 0.890, 0.664 and 0.660, respectively. In the main phase, the correlation coefficients are 0.858, 0.823 and 0.541, respectively. Empirical formulas for the energy flux as functions of the Sym-H and the Poynting flux are constructed. In the main phase, $ {J}_{{i}^{+}}={10}^{5.324 \pm 0.581}\times {\mathrm{S}\mathrm{y}\mathrm{m}{\text{-}}H}^{1.465 \pm 0.340} $, $ {J}_{{i}^{+}}={10}^{6.469 \pm 0.798}\times $$ {{S}_{\mathrm{d}\mathrm{c}}}^{0.888 \pm 0.703} $. In the initial phase, due to the rapid injection of the energy during geomagnetic disturbance and the rapid energy acquisition of ionospheric ions, the ion energy flux is highly correlated with the geomagnetic disturbance indices. Meanwhile, the energy flux increases by two orders of magnitude in the main phase. The Joule dissipation caused by the downward Poynting flux is one of the important sources of ion energy acquisition, and a strong correlation is observed.
Virtual Height Variation during Plasma Bubble Evolution Associated with Plasma Blob in Low Latitude Ionosphere
WANG Zheng, SHI Jiankui, WANG Guojun, WANG Xiao, SHANG Sheping, CHENG Zhengwei
2022, 42(1): 65-72. doi: 10.11728/cjss2022.01.210316032
The observations and theoretical analysis suggest that ionospheric plasma blob could form during the early stage of plasma bubble evolution. In this paper we perform three cases in which ionospheric plasma blob and bubble were associated, to study the virtual height variation during plasma bubble evolution with continuous observations by Digital ionosonde. The cases were over station Vanimo (Geographic 2.7°S, 141.3°E; Geomagnetic 11.2°S, 146.2°W) and Hainan (Geographic 19.5°N, 109.1°E; Geomagnetic 9.1°N, 179.1°W), both in the low latitude region in East Asia sector while in different Hemispheres. The results show that: previous studies suggested that, 2 h before blob occurred, plasma vertical drift velocity would turn from upward (eastward electric field) to downward (westward electric field), but the feature did not show in this study. In our three cases, the turning time was 6 h before blob, or the turning direction was from downward to upward. In addition, 1 h before blob occurred, the ionospheric plasma had sudden compression trend, such as decrease of downward velocity, turn from downward to upward, or increase of upward velocity. This compression was more close to plasma blob, and not limited to the turning of drift direction.
Statistics of Ion Downward Flows in the Ionosphere during Subauroral Polarization Streams
WEI Dong, YU Yiqun
2022, 42(1): 73-81. doi: 10.11728/cjss2022.01.200724066
During geomagnetically disturbed times, enhanced westward plasma flows appear in the duskside subauroral ionosphere and are termed as Subauroral Polarization Streams (SAPS). SAPS are usually believed as one of the most important features of the magnetosphere-ionosphere coupling and play an important role in regulating the ionospheric dynamics. Generally, SAPS can give rise to local ion upward flows, but there are few studies on ion downward flows. Based on the observations of DMSP satellites during 16 magnetic storm from 2001 to 2015, we find 102 cases with ion downward flows in all the 483 SAPS events. The occurrence rate of ion downward flows, the distribution of ion downward flows in the Northern and Southern Hemispheres, and the favored conditions for the formation of ion downward flows are further analyzed in these SAPS events. The results show that the occurrence rate of ion downward flow is relatively low in SAPS events, and the number and distribution of ion downward flow events are different on the two hemispheres. A linear relationship is found between the SAPS and ion downward flow velocities. Furthermore, the formation of ion downward flow is most probably caused by the combined effects of ambipolar diffusion and gravity. The intensity of ion thermal movement has significant influence on the velocity of ion downward flow. These results will help us to further understand the regulating effects of SAPS on the ionosphere.
A Characterization Method of Global Ionospheric Irregularities Activities Based on GNSS Data
WU Jiayan, ZHEN Weimin, OU Ming, YU Xiao, CHEN Longjiang
2022, 42(1): 82-90. doi: 10.11728/cjss2022.01.201009088
For the problem of how to use GNSS (Global Navigation Satellite System) data to monitor ionospheric disturbance, this paper proposes a method for characterizing global ionospheric disturbances based on GNSS data. This article uses GNSS (Global Navigation Satellite System) observations of approximately 400 ground stations to calculate the standard deviation of the rate of change of TEC (Total Electron Content)–ROTI (Rate of TEC Index, ROTI), as an ionospheric disturbance observation and projected onto a grid of latitude and longitude to form a 1-hour resolution ROTI map. ROTI maps can reflect ionospheric irregularities ranging from several kilometers to tens of kilometers. The article analyzes the results of ROTI maps when the ionosphere is calm and disturbed during March 2015. And results show that such large-scale irregularities are mainly distributed in high latitude and low latitude regions. During a magnetic storm, ROTI maps show changes in numerical values and disturbance areas. ROTI maps can represent global ionospheric disturbances to a certain extent. On this basis, the index of Global ROTI Disturbance (Global ROTI index, GROTI) is proposed and the analysis results show that GROTI in high regions has a good correlation with the geomagnetic index Kp and AE index.
Computer-aided Chemical Kinetic Modeling in Near Space
ZHANG Sicong, CHENG Wei, WANG Chengzhi, LI Huijun
2022, 42(1): 91-102. doi: 10.11728/cjss2022.01.201019094
As the typical processes in stratospheric photochemical reactions, four systems with different complicities in mass balance equations are selected as the bench mark cases, to show the efficiency and convenience for application of the Chemical Kinetics Preprocess (KPP) tool in Near Space chemical modelings. Focusing on the large rigid ODE equations in the model, six different numerical calculation schemes are selected (rodas, ros3, ros4, rosenbrock, sdirk, seulex), to realize the discrete representation of ODE equations, and automatically generate the required calculation code. On this basis, the numerical simulation experiments of stratospheric photochemical processes are carried out, focusing on: (i) the computational efficiency and stability of the numerical calculation schemes; (ii) the evolution of main chemical components of each system with time; (iii) the influence of the complexity of the photochemical system on the changes of the main components of each model. Simulation results show that the KPP tool can effectively cope with the increase of the complexity of atmospheric chemical reaction system in adjacent space, shorten the modeling and testing period of atmospheric chemical model, and provide effective technical support for the research of the atmospheric chemical process in adjacent space.
Impact of Coriolis Force in the Falling-sphere Detection of Near-Space Atmospheric Environment
FAN Zhiqiang, SHENG Zheng, ZHAO Zengliang, ZHOU Yufeng, ZHANG Yisheng, JIANG Jun
2022, 42(1): 103-116. doi: 10.11728/cjss2022.01.201203104
Meteorological rocket falling-sphere detection technology is an important method for detecting atmospheric environment in near space. The influence of Coriolis force was usually ignored in the data processing of falling-sphere detection. The empirical forecasting models were used to build a forward simulation model for falling-sphere detection, and a parameter inversion model was established according to the principle of falling-sphere detection. The forward model and inversion model were combined to simulate the inversion error of retrieved parameters when ignoring the Coriolis force term. In the height range of 95 ~ 100 km, the inversion errors of atmospheric parameters such as temperature, density, zonal wind and meridional wind are relatively large, and the error characteristics vary with the latitude of the detection point and the initial velocity in each direction. After that, the inversion error gradually decreases as the height decreases. When it drops to about 70km, the influence caused by the Coriolis force term is gradually negligible. The research results show that the influence of the Coriolis force term can’t be ignored during the data processing of falling-sphere detection. The results of this paper have an important reference value for improving the accuracy of atmospheric parameter inversion for falling-sphere detection.
Infrared Spectroscopic Detection of Organic Matter on the Surface of Asteroids
TANG Hong, ZHOU Chuanjiao, LI Xiongyao, LIU Jianzhong, MO Bing, YU Wen, ZENG Xiaojia
2022, 42(1): 117-126. doi: 10.11728/cjss2022.01.201127103
The organic matter in the asteroid has recorded the formation and evolution of organic matter in the early solar system, which provides an important basis for the research on the emergence of early life precursors on Earth, and is significant for the origin and evolution of life. In this study, the composition, types and occurrence of possible organic matter in asteroids have been analyzed. The infrared spectra and influence factors of organic matter have been discussed by simulation experiments. Infrared spectra of three representative organic matter (i.e., glycine, glucose, and eicosane) at different temperatures were obtained by in-situ infrared spectroscopy measurements under temperatures ranging from – 60°C to 30°C in vacuum. In addition, the main types of organic matter of the Murchison carbonaceous chondrite were identified using the infrared spectrometer. The results show that the infrared spectral of different organic compounds are related to the types, structures, temperatures, and pressures. The identification marks of main organic matter on the surface of the asteroids have been determined. And the preliminary parameters of infrared spectrometer for exploring organic matter in asteroids are presented.
Formation and Degradation of Lunar Crater Ray and Possible Geochronology Application
HOU Xuting, CAO Haijun, FU Xiaohui, ZHANG Jiang, LI Bo, LING Zongcheng
2022, 42(1): 127-135. doi: 10.11728/cjss2022.01.201014091
Crater rays are formed during a cratering event as target material is ballistically ejected to distances of many crater radii forming narrow, generally high albedo, approximately linear features extending outward from the crater. The formation and degradation of lunar crater ray is one of the hot topics in lunar science. In this paper, the current understanding of crater ray origin, their different types on lunar surface, and the processes related with degradation of lunar crater ray systems are summarized. After the formation of the crater rays, the fresh and bright ejecta materials around the crater gradually mature under the joint action of a variety of geological processes, and reflectivity gradually disappears in accordance with the background. The OMAT profiles of young craters with various ages were compared. It is found that the average OMAT profile of crater ray could be fitted with the power law function; and that the shape of the OMAT profiles is strongly dependent on the exposure time on lunar surface as well as the crater age. This suggests that by using young crater with ray and known age as the reference, an empirical equation between the shape parameter and age could be built. This study provides a new method for dating young lunar craters.
GEOS Photometric Signature Classifications Based on Observations of FocusGEO Telescopes
ZHAO Xiaofen, ZHENG Jinghui, MAO Yindun, YU Yong, WANG Kunpeng, WEN Changli
2022, 42(1): 136-143. doi: 10.11728/cjss2022.01.200928086
Ground-based optical-electrical observation is the main approach to obtain the Geostationary Earth Orbit (GEO) targets’ optical characteristics. Light curve classification was studied based on the photometry observations of FocusGEO telescope at Lijiang Station from December 2017 to June 2019. A new classification system was introduced based on the statistical analysis of GEO satellite light curve features. Moreover, the correlation between light curve classification and satellites’ bus type was analyzed. Results show that photometric signatures of 197 GEO satellites can be classified into six classes and each class can be qualitatively explained by the actual satellite structure. Approximately 90% of these satellites appear to belong to three of six different classes. However, light curve classification has no significant correlation to satellites’ bus types, but for the satellites with the same or similar bus types in each class, the light curves resemble each other. The classification system can aid to identify cluster GEO targets and provide the basis for anomaly detection and physical characteristics research, which is of great significance for space situational awareness.
Thermal Control Design and Validated for MEO Navigation Satellites
LIN Shifeng, LI Kai, LIN Baojun, JIANG Guizhong, MA Errui
2022, 42(1): 144-152. doi: 10.11728/cjss2022.01.200930087
In consideration of the configuration design, orbital attitude, and operation mode of the MEO navigation satellite, both passive and active thermal designs including conduction, diffusion, insulation, switch or proportional control and multistage control strategy are used in the satellite thermal system to satisfy the strict temperature requirements. For high-power payloads and phased array antennas, heat pipe networks along with extended radiators are employed; for temperature-sensitive equipment like battery and atomic clock, thermal insulation along with active control are applied. On-orbit fault diagnosis and automatic isolation designs are utilized in the thermal control software to improve the on-orbit autonomous operation capability. The satellite thermal design is validated by the ground thermal balance test and the performance of satellites in orbit. Validation results illustrate that on-board equipment satisfies temperature requirements, and the design margin and temperature trend lines well with expectation.
Analysis and Simulation of Tracking Algorithm for High Orbit Weak Signal
YANG Xiaojiang, WANG Juan
2022, 42(1): 153-162. doi: 10.11728/cjss2022.01.201016093
Autonomous Navigation Technology of high orbit spacecraft is one of the new aerospace techniques to be developed urgently in China, which is widely used in communication navigation, meteorology, early warning and other fields. High orbit navigation receiver provides a convenient and effective means for autonomous navigation and positioning of high orbit spacecraft. In the high dynamic environment, the carrier frequency, phase and pseudo code phase change greatly with the carrier motion. Because the influence of Doppler frequency change introduced by carrier dynamics on PN code tracking loop can be eliminated by carrier assistance, the dynamic performance of receiver mainly depends on the performance of carrier tracking module. The increase of propagation path of high orbit, high dynamic signal leads to the problems of large loss of received signal path and weak signal of high orbit navigation receiver. Through carrying out special research on high orbit weak signal tracking technology, through many times of simulation and analysis, through reasonable design of loop noise bandwidth and adjustment of pre-integration time and other measures, it can effectively and stably process and track the navigation weak signal of –173 dBw. The algorithm has been applied to the Chang’E-5 high orbit navigation receiver project. It provides the technical guidance and index reference for later engineering application such as flying around the Moon.
Linear Spline and CNN-LSTM for Missing Values Imputation of Beidou Satellite Radiation Dose Data
YANG Xu, CUI Ruifei, TIAN Chao, HU Sihui, JIANG Jianmin, XU Peikang
2022, 42(1): 163-169. doi: 10.11728/cjss2022.01.201116100
Aiming at the problem of missing radiation dose detection data of a certain Beidou satellites, a processing method based on linear spline and CNN-LSTM is proposed. First, analyze the characteristics of the data and decompose it into long-term trend items, a linear spline method is used to complete the missing value processing. For the seasonal fluctuation items, the temporal and spatial change rules are analyzed, and on this basis, the CNN and LSTM fusion neural network structure is designed to complete the processing of the seasonal fluctuation items. Experiments show that, comapred with the linear interplation method and the Fourier transform method, our approach performs better in the prediction with an average relative error of 0.008 and a correlation coefficient of 0.855. At the same time, the prediction accuracies of our approach and the single LSTM and single CNN network models are compared, similarly the predictions of our approach is more consistent with the observed data, and has a smaller deviation. The results show that the approach in this paper can better solve the problem of continuous missing values of Beidou satellites observations, which lays a foundation for the further scientific research based on the dataset.
A Method for Estimating Differential Code Deviation of Ground-based GNSS Receiver
ZHOU Zhonghua, WAN Xiang, CHENG Yan, LIU Zhizhong, WANG Wenjun, ZHANG Xueli
2022, 42(1): 170-178. doi: 10.11728/cjss2022.01.201026096
The difference of code pseudo-range between different frequency points of GNSS will lead to the DCB of the signal. The DCB of GNSS satellite and ground receiver can cause an accuracy error of about 25 ns, which must be corrected. Against to this problem, this paper proposes a differential code deviation estimation method for ground-based GNSS receivers. This method can obtain the DCBr of ground GNSS receiver and satellite DCBs at the same time, and effectively solve the problem of ground GNSS receiver DCBr acquisition. Through the comparison and statistical analysis of the estimated satellite DCBs and the values published by code, the results show that the RMS mean error of the difference between the two satellites DCBs (C1P2) is less than 0.3541 ns, and the estimation accuracy of ground-based GNSS receiver DCBr (C1P2) is better than 1.6105 ns.