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A tentative study for the prediction of the CME related geomagnetic storm intensity and its transit time

science china(Technological sciences) 2005年第6期48卷 648-668页

作者： zhao xinhua1,2 & feng xueshang1,3.1. sigma weather group,{3., center for space science and applied re-search, chinese academy of sciences, Beijing 100080, china 2. Graduate School of the chinese academy of sciences, Beijing 10003., china 3. School of Geophysics and Geoinformation Systems, china University of Geosciences, Beijing 100083. china sigma weather group Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China Graduate School of the chinese academy of sciences Beijing China School of Geophysics and Geoinformation Systems China University of Geosciences Beijing China

Using 80 CME-ICME events during 1997.1―2002.9, based on the eruptive source locations of CMEs and solar magnetic field observation at the photosphere, a current sheet magnetic coordinate (CMC) system is established in order to study the propagation of CME and its geoeffectiveness. In context of this coordinate system, the effect of the eruptive source location and the form of heliospheric current sheet (HCS) at the eruptive time of CME on the geomagnetic storm intensity caused by CME and the CME’s transit time at the Earth is investigated in detail. Our preliminary conclusions are: 1) The geomagnetic disturbances caused by CMEs tend to have the so-called “same side-opposite side effect”, i.e. CMEs erupt from the same side of the HCS as the earth would be more likely to arrive at the earth and the geomagnetic disturbances associated with them tend to be of larger magnitude, while CMEs erupting from the opposite side would arrive at the earth with less probability and the corresponding geomagnetic disturbance magnitudes would be relatively weaker. 2) The angular separation between the earth and the HCS affect the corresponding disturbance intensity. That is, when our earth is located near the HCS, adverse space weather events occur most probably. 3. The erupting location of the CME and its nearby form of HCS will also affect its arrival time at the earth. According to these conclusions, in this context of CMC coordinate we arrive at new prediction method for estimating the geomagnetic storm intensity (Dstmin) caused by CMEs and their transit times. The application of the empirical model for 80 CME-ICME events shows that the relative error of Dst is within 3.% for 59% events with Dstmin≤?50 nT, while the averaged absolute error of transit time is lower than 10 h for all events.

关键词： coronal mass ejections, current sheet magnetic coordinate system, geomagnetic storm intensity, transit time, prediction method.

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Numerical study of successive CMEs during November 4―5, 1998

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science china(Technological sciences) 2008年第10期51卷 1600-1610页

作者： ZHOU YuFen & feng xueshang sigma {3. group, State key laboratory for space {3., center for space science and applied {13.search, chinese academy of sciences, Beijing 100190, china sigma weather group State Key Laboratory for Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China

We present the solar-terrestrial transit process of three successive coronal mass ejections (CMEs) of November 4―5, 1998 originating from active region 83.5 by using a time-dependent three-dimensional magnetohydrodynamics (MHD) simula-tion. These CMEs interacted with each other while they were propagating in inter-planetary space and finally formed a "complex ejecta". A newly developed SIP-CESE MHD model was applied to solve MHD equations numerically. The quiet solar wind was started from Parker-like 1D solar wind solution and the magnetic field map was calculated from the solar photospheric magnetic field data. In our simulation, the ejections were initiated using pulse in the real active region 83.5. The interplanetary disturbance parameters, such as speed, direction and angular size of the expanding CME, were determined from the SOHO/LASCO data with the cone-model. We discussed the three-dimensional aspects of the propagation, in-teraction and merging of the three ejections. The simulated interplanetary shocks were compared with the nearby-Earth measurement. The results showed that our simulation could reproduce and explain some of the general features observed by satellite for the "complex ejecta".

关键词： complex ejecta three-dimensional MHD simulation SIP-CESE MHD model

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A comparative study on 3.D solar wind structure observed by Ulysses and MHD simulation

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science Bulletin 2005年第7期50卷 672-678页

作者： feng xueshang, XIANG Changqing, ZHONG Dingkun & FAN Quanlin sigma {3. group, key laboratory of space weather key Labo- ratory of Geospace Environment and Geodesy, Ministry of Education, center for space science and applied re{13., chinese academy of sciences, Beijing 100080, china sigma weather group Key Laboratory of Space Weather Beijing China key Labo-ratory of Geospace Environment and Geodesy Ministry of Education Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China

During Ulysses’ first rapid pole-to-pole transit from September 1994 to June 1995, its observations showed that middle- or high-speed solar winds covered all latitudes except those between ?20° and +20° near the ecliptic plane, where the velocity was 3.0―450 km/s. At poleward 40°, however, only fast solar winds at the speed of 700―870 km/s were observed. In addition, the transitions from low-speed wind to high-speed wind or vice versa were abrupt. In this paper, the large-scale structure of solar wind observed by Ulysses near solar minimum is simulated by using the three-dimensional numerical MHD model. The model com- bines TVD Lax-Friedrich scheme and MacCormack II scheme and decomposes the calculation region into two re- gions: one from 1 to 22 Rs and the other from 18 Rs to 1 AU. Based on the observations of the solar photospheric magnetic field and an addition of the volumetric heating to MHD equations, the large-scale solar wind structure mentioned above is reproduced by using the three-dimensional MHD model and the numerical results are roughly consistent with Ulysses’ observations. Our simulation shows that the initial magnetic field topology and the addition of volume heating may govern the bimodal structure of solar wind observed by Ulysses and also demonstrates that the three-dimensional MHD numerical model used here is efficient in modeling the large-scale solar wind structure.

关键词： Ulysses observation solar wind structure numerical simulation.

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WIND observations of plasma waves inside the magnetic cloud boundary layers

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science Bulletin 2005年第18期 85-90页

作者： WEI fengsi1 , ZHONG Dingkun1,2, feng xueshang1, YANG Fang1,2 & LIU Rui 1 1. {3. weather group, laboratory for space weather, center for space science and applied {13.search, chinese academy of sciences, Beijing 100080, china 2. Graduate School, chinese academy of sciences, Beijing 100049, china

Based on the WIND observational data for the plasma waves from thermal noise receptor (TNR) working on the frequency 4―256 kHz and the solar wind and the magnetic fields, we analyze the plasma wave activities in the 60 magnetic cloud’s boundary layers (BLs) and find that there are often various plasma wave activities in the BLs, which are different from those in the adjacent solar wind (SW) and the magnetic clouds (MC). The basic characteris-tics are that: (1) the enhancement of the Langmuir wave near the electronic plasma frequency (fpe) is a dominant wave ac-tivity, which occupies 75% investigated samples; (2) the events enhanced both in the langmuir and ion acustic (f re about 60% of investigated samples; (3. broadband, continuous enhancement events in the plasma wave activities were observed in the whole frequency band of TNR, and about 3.% of the 60 samples, however, were not observed in the SW and the MC investigated events; (4) although the ratio of the temperatures between the electon and proton, Te/Tp≤1, the ion caustic wave enhancement activities are still often observed in the BLs, which makes it difficult to ex- plain them by the traditional plasma theory. New results reported in this paper further show that the magnetic cloud’s BL is an important dynamic structure, which could provide useful diagnosis for understanding the cloud’s BL physics and could expand a space developing space plasma wave theory.

关键词： solar wind magnetic cloud boundary layer plasma waves.

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Flare/CME events triggered by the interaction between two types of magnetic flux appearance

Flare/CME events triggered by the interaction between two ty...

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第十二届全国日地空间物理学术讨论会

作者： Song Wenbin~1 feng xueshang~1 Wang Jingxiu~2 (1 sigma {3. group,State key laboratory for space {3.,center for space science and applied {13.search,chinese academy of sciences,Beijing 100080) (2 National Astronomical Observatories,chinese academy of sciences,Beijing 100012)

＜正＞As a large-scale solar activity,coronal mass ejection （CME） is the primary driver of disastrous space weather in Sun-Earth environment.A huge monopolar sunspot within an extended bipolar region （EBR） shown i...

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An asynchronous and parallel time-marching method: Application to three-dimensional MHD simulation of solar wind

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science china(Technological sciences) 2009年第10期52卷 2895-2902页

作者： SHEN Fang feng xueshang SONG WenBin sigma weather group State Key Laboratory for Space WeatherCenter for Space Science and Applied ResearchChinese Academy of SciencesBeijing 100190China

An asynchronous and parallel time-marching method for three-dimensional (3.) time-dependent magnetohydrodynamic (MHD) simulation is used for large-scale solar wind simulation. It uses different local time steps in the corona and the heliosphere according to the local Courant-Friedrichs-Levy (CFL) conditions. The solar wind background with observed solar photospheric magnetic field as input is first presented. The simulation time for the background solar wind by using the asynchronous method is recision. Then, we choose the coronal mass ejection (CME) event of 13.November, 2003.as a test case. The time-dependent variations of the pressure and the velocity configured from a CME model at the inner boundary are applied to generate transient structures in order to study the dynamical interaction of a CME with the background solar wind flow between 1 and 23. Rs. This time-marching method is very effective in terms of computation time for large-scale 3. time-dependent numerical MHD problem. In this validation study, we find that this 3. MHD model, with the asynchronous and parallel time-marching method, provides a relatively satisfactory comparison with the ACE spacecraft obser- vations at L1 point.

关键词： asynchronous parallel MHD simulation CME

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Observations of the field-aligned residual flow inside magnetic cloud structure

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science china(Technological sciences) 2009年第9期52卷 2555-2566页

作者： LI HuiJun feng xueshang ZUO PingBing XIE YanQiong sigma weather group State Key Laboratory for Space WeatherCenter for Space Science and Applied ResearchChinese Academy of SciencesBeijing 100190China Graduate University of the chinese academy of sciences Beijing 100039China Institute of Meteorology PLA University of Science and TechnologyNanjing 211101China

In this paper,we report two MC events observed by WIND spacecraft with good examples of fieldaligned residual flow inside the MC structure. For both events,the co-moving frames are determined through the deHoffman-Teller (HT) analysis and the axial orientations are inferred by the newly developed minimal residue (MR) method. The nature coordinate system for both events are constructed with velocity of the HT frame and the inferred MC axis,the field and flow remaining in the HT frame are analyzed at this coordinate system. As a result,we find that the residual flows in the co-moving HT frame of the two MC events are almost anti-parallel to the helical magnetic field. We speculate that the field-aligned residual flows are large scale coherent hydrodynamic vortices co-moving with the MCs at the supersonic speed near 1 AU. Data analyses show that the event in slow ambient solar wind is expanding at 1 AU and another one in fast solar wind does not show apparent expansion. Proton behaviors for both events are quasi-isothermal. Accelerated HT analysis shows that both events have no suitable HT frame with constant accelerations,which suggests that both events may be moving at the constant speed near 1 AU under the assumptions of the HT analysis. For both events,the ratio of the dynamic pressure to the magnetic pressure is larger than that of the thermal pressure to magnetic pressure,which suggests that the dynamic effects due to the plasma flows remaining in the co-moving HT frame are more important than the thermal effects in the study of MC evolution and propagation.

关键词： interplanetary medium solar wind magnetic cloud (MC) Sun:coronal mass ejections (CMEs)

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3. numerical study of typical CME event: The 2010-04-03.event

3D numerical study of typical CME event: The 2010-04-03 even...

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2014年中国地球科学联合学术年会——专题29：空间天...

作者： Yufen Zhou xueshang feng xinhua {3. sigma weather group State Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Science

＜正＞The coronal mass ejection（CME）event on April 3.2010 is the first fast CME observed by STEreO SECCHI/HI for the full Sun-Earth *** an event provides us a good opportunity to study the propagation and evolution of CME from the Sun up to 1 *** this paper,we study the time-dependent evolution and propagation of this event from the Sun to Earth using the 3. SIP-CESE MHD *** CME is initiated by a simple spherical plasmoid model:a spheromak magnetic structure with high speed,high pressure and high plasma density *** find that the results can successfully reproduce the observations in the STEreO

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WIND observations of plasma waves inside the magnetic cloud boundary layers

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chinese science Bulletin 2005年第18期50卷 2051-2056页

作者： WEI fengsi ZHONG Dingkun feng xueshang YANG Fang LIU Rui sigma weather group Laboratory for Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100080 China Graduate School Chinese Academy of Sciences Beijing 100049 China

关键词：边界层等离子体波磁场 Langmuir波频率分布

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The heating of the solar transition region

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research in Astronomy and Astrophysics 2010年第6期10卷 529-532页

作者： Wen-Bin Song Xue-Shang feng Fang Shen sigma weather group State Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100190 China

The temperature curve in the solar chromosphere has puzzled astronomers for a long time. referring to the structure of supergranular cells, we propose an inductive heating model. It mainly includes the following three steps. （1） A small-scale dynamo exists in the supergranulation and produces alternating small-scale magnetic fluxes; （2） The supergranular flow distributes these small-scale fluxes according to a regular pattern; （3. A skin effect occurs in the alternating and regularly-distributed magnetic fields. The induced current is concentrated near the transition region and heats it by resistive dissipation.

关键词： Sun transition region -- Sun granulation

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