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Mechanism of proton anisotropic velocity distribution in the solar wind

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Science China(Physics,Mechanics & Astronomy) 2003年第1期46卷 78-83页

作者：敖先志沈迹涂传诒 Department of Geophysics Peking UniversityBeijing 100871China

Although it has been long that spacecraft observed the anisotropy of velocity protons in the solar wind, there is still not a reasonable explanation. In this paper we try to give an explanation from the diffusion plateau of protoncyclotron resonance predicted by the quasi-linear theory for the resonance between the protons and the parallel propagating waves. We consider the effect of dispersion relation on diffusion plateau and notice that the diffusion plateau we have got by using cold plasma dispersion relation accords with the density contours in the velocity phase space detected at 0.3 AU in fast solar wind. For explaining proton distributions obtained in the fast solar wind from 0.7 AU to 1 AU hot plasma dispersion relation should be considered. We also give a theoretical relation of proton thermal anisotropy A and plasma parameter β.

关键词： solar wind, cyclotron resonance, quasi-linear theory, diffusion plateau.

The polar ionosphere at Zhongshan Station on May 11, 1999, the day the solar wind almost disappeared

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Science China Mathematics 2002年第Z1期45卷 161-166页

作者：胡红桥刘瑞源刘勇华杨惠根刘顺林张北辰艾勇 N. Sato B. J. Fraser Polar Research Institute of China Shanghai 200129 China College of Electronic Information Wuhan University Wuhan 430072 China National Institute of Polar Research Tokyo 173 Japan Department of Physics University of Newcastle Australia

The solar wind almost disappeared on May 11,1999: the solar wind plasma density and dynamic pressure were less than 1cm^(-3) and 0.1 nPa respectively, while the interplanetary mag- netic field was northward. The polar ionospheric data observed by the multi-instruments at Zhong- shan Station in Antarctica on such special event day was compared with those of the control day (May 14). It was shown that geomagnetic activity was very quiet on May 11 at Zhongshan. The magnetic pulsation, which usually occurred at about magnetic noon, did not appear. The iono- sphere was steady and stratified, and the F_2 layer spread very little. The critical frequency of day- side F_2 layer, f_0F_2, was larger than that of control day, and the peak of f_0F_2 appeared 2 hours earlier. The ionospheric drift velocity was less than usual. There were intensive auroral E_s appearing at magnetic noon. All this indicates that the polar ionosphere was extremely quiet and geomagnetic field was much more dipolar on May 11. There were some signatures of auroral substorm before midnight, such as the negative deviation of the geomagnetic H component, accompanied with auroral E_s and weak Pc3 pulsation.

关键词： solar wind, Antarctica, Zhongshan Station, polar ionosphere, geomagnetic pulsation.

Interannual variability of Antarctic Oscillation and its influence on East Asian climate during boreal winter and spring

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Science China Earth Sciences 2006年第5期49卷 554-560页

作者： FAN Ke1,2,3 & WANG Huijun2 1. Nansen-Zhu International Research Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China 2. Department of Atmospheric Science, Yunnan University, Kunming 650091, China 3. Graduate University of the Chinese Academy of Sciences, Beijing 100049, China Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Department of Atmospheric Science Yunnan University Kunming China Graduate University of the Chinese Academy of Sciences Beijing China

The interannual variability of Antarctic Oscillation (AAO) and its influence on East Asian climate during both boreal winter and spring are addressed. The results show that the positive AAO anomaly decreases the cold activity over East Asia during both boreal winter and spring. AAO-related barotropic meridional teleconnection from Antarctic to Arctic is found through analysis of mean me- ridional circulations. This meridional teleconnection is remarkable over Eurasia during boreal winter and over the Pacific Ocean during boreal spring. The results also show that zonal mean zonal wind at high latitudes in Southern Hemisphere has well positive correlation with that of Eurasia during boreal winter and has negative correlation with Pacific North American teleconnection (PNA) during boreal spring, which again display the meridional teleconnection. Thus, local meridional teleconnection is a possible linkage for interaction of circulations at mid-high latitudes between both hemispheres.

关键词： Antarctic Oscillation, Eurasian west wind, meridional teleconnection, mean meridional circulation.

A new algorithm for microwave radiometer remote sensing of sea surface salinity and temperature

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Science China Earth Sciences 2006年第11期49卷 1204-1211页

作者： YIN Xiaobin1, LIU Yuguang1, WANG Zhenzhan2 & XIU Peng1 1. Physical Oceanography Laboratory, Ocean University of China, Qingdao 266003, China 2. Center for Space and Applied Research, Chinese Academy of Sciences, Beijing 100080, China Physical Oceanography Laboratory Ocean University of China Qingdao China Center for Space and Applied Research Chinese Academy of Sciences Beijing China

The microwave radiation of the sea surface, which is denoted by the sea surface brightness temperature, is not only related with sea surface salinity (SSS) and temperature (SST), but also influenced by sea surface wind. The errors of wind detected by satellite sensor have significant influences on the accuracy of SSS and SST retrieval. The effects of sea surface wind on sea surface brightness temperature, i.e. △Th,v, and the relations among △Th,v, wind speed, sea surface tempera- ture, sea surface salinity and incidence angle of observation are investigated. Based on the investi- gations, a new algorithm depending on the design of a single radiometer with double polarizations and multi-incidence angles is proposed. The algorithm excludes the influence of sea surface wind on SSS and SST retrieval, and provides a new method for remote sensing of SSS and SST.

关键词： microwave radiometer, sea surface temperature, sea surface salinity, wind, brightness temperature.

Magnetic reconnection structures in the boundary layer of an interplanetary magnetic cloud

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Science China(Technological Sciences) 2004年第1期47卷 6-14页

作者： WEI Fengsi LIU Rui FENG Xueshang ZHONG Dingkun YANG Fang Key Laboratory for Space Weather Chinese Academy of Sciences Beijing 100080 China Key Laboratory for Space Weather Chinese Academy of Sciences Beijing 100080 China Key Laboratory for Space Weather Chinese Academy of Sciences Beijing 100080 China Key Laboratory for Space Weather Chinese Academy of Sciences Beijing 100080 China Key Laboratory for Space Weather Chinese Academy of Sciences Beijing 100080 China

An interplanetary magnetic diffusion region was detected by wind during 0735-0850 UT on May 15, 1997 when the front boundary layer of a magnetic cloud passed through the spacecraft about 190 earth radii upstream of the earth. The main signals of magnetic reconnection processes are: (i) Flow reversal was detected at about 0810 UT. The counter-streaming flows have the speeds of about 65 and 41 km/s, respectively, with an angle of about 140 degree between them. (ii) Hall magnetic field was detected. The Hall fields ?By and +By, perpendicular to the X-Z plane, with their magnitude up to ～7.0 nT, are superposed upon a guide field about 12 nT. (iii) Alfvenic fluctuations are obviously intensified inside the reconnection region; at the front boundary of the reconnection region, a slow-mode-like discontinuity was detected. (iv) Ions are heated intensively inside the reconnection region, with their temperature three times higher than that ahead of the boundary layer; electrons are also heated, with a little enhancement in their temperature. The above observations indicate that magnetic reconnection processes could take place in interplanetary space. Keywords solar wind - interplanetary magnetic clouds - magnetic reconnection

关键词： solar wind, interplanetary magnetic clouds, magnetic reconnection.

Study of Solar Corona in China

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空间科学学报 2006年第Z1期26卷 79-89页

作者： FENG Xueshang ZHAO Xinhua State Key Laboratory for Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100080 China State Key Laboratory for Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100080 China

Considerable progress for the study of solar corona physics has been achieved by China's space physics community. It involves the theoretical study of coronal process of solar active phenomena, solar wind origin, acceleration of solar wind and coronal mass ejections, observational and numerical study of these problems and prediction methods of solar eruptive activities (such as flares/CMEs). Here is a brief summary of the progress in this area. Main progress is put upon the following three topics: corona and solar wind, numerical method, prediction method.

关键词： Corona and solar wind, Numerical method, Prediction method