CME和冕洞边缘结构的可能关系

本文分析了１９８０ 、１９８４ 和１９８９ 年ＳＭＭ 卫星观测到的１４０ 次日冕物质抛射（ＣＭＥ） 事件在时空分布上与“冕洞边缘结构”、耀斑爆发和爆发日珥等事件的相关关系结果表明, ＣＭＥ 事件与日冕边缘结构的关系最密切此外, ＣＭＥ与赤道冕洞具有同步的长期演化关系由此认为, 冕洞边缘结构对ＣＭＥ的可能贡献是不可忽视的     

依据实验室高温条件下获得的岩石物理特性建立乌兹别克地震活动区域地壳岩石物理模型

依据实验室高温条件下获得的岩石物理特性建立乌兹别克地震活动区域地壳岩石物理模型巴卡耶夫Ｍ．Ｋｈ，阿布诺基莫夫Ａ．Ｋｈ（乌兹别克斯坦科学院地震学研究所，塔什干）ＰＥＴＲＯＰＨＹＳＩＣＡＩＭＯＤＥＬＳＯＦＴＨＥＥＡＲＴＨ＇ＳＣＲＵＳＴＩＮＳＥＩＳＭＩＣＡ...     

MATHEMATICAL MODEL FOR SEDIMENT TRANSPORT CAPACITY OF HYPERCONCENTRATED FLOW

ＭＡＴＨＥＭＡＴＩＣＡＬＭＯＤＥＬＦＯＲＳＥＤＩＭＥＮＴＴＲＡＮＳＰＯＲＴＣＡＰＡＣＩＴＹＯＦＨＹＰＥＲＣＯＮＣＥＮＴＲＡＴＥＤＦＬＯＷＩＮＤＩＶＥＲＳＩＯＮＣＡＮＡＬＳ￥ＣＡＯＲｕｘｕａｎ；ＷＵＰｅｉａｎ；ＲＥＮＸｉａｏｆｅｎｇａｎｄＬＩＵＭｉｎｇ...     

COMPREHENSIVE MANAGEMENT OF SMALL WATERSHED FOR SOIL AND WATER CONSERVATION IN CHINA

ＣＯＭＰＲＥＨＥＮＳＩＶＥＭＡＮＡＧＥＭＥＮＴＯＦＳＭＡＬＬＷＡＴＥＲＳＨＥＤＦＯＲＳＯＩＬＡＮＤＷＡＴＥＲＣＯＮＳＥＲＶＡＴＩＯＮＩＮＣＨＩＮＡＤＵＡＮＱｉａｏｆｕ２Ｉ．ＧＥＮＥＲＡＬＣｈｉｎａｉｓｏｎｅｏｆｔｈｅｃｏｕｎｔｒｉｅｓｓｕｆｆｅｒｉｎ...     

日冕物质抛射和射电爆发

日冕物质抛射（ＣＭＥ） 是一个极为复杂的动力学过程本文基于开放场、闭合场的物理条件及射电爆发理论, 研究了ＣＭＥｓ 与相伴随的射电Ⅱ型、Ⅲ型、Ⅳ型爆发、软χ射线增强及太阳耀斑的关系给出了它们相伴随的条件： 当磁通量喷发, 能量释放时, 等离子体将被加速如果加速区在开放场, 可能会产生Ⅲ型爆发; 如果是闭合场, 被加速的高能质子和高能电子将被磁环捕获高能质子在磁环腿部呈损失锥分布, 当Ｅ≥ＥＴ 时会产生软χ射线增强随着磁环内的热压Ｐ和磁压Ｐｍ 的升高, 当β≥βＴ 时, 磁环将炸裂, 产生ＣＭＥｓ抛射出的高能相对论电子绕开放场线作螺旋飞行时, 会产生Ⅳ型爆发; 而亚相对论电子以零入射角沿开放磁场线逃逸时, 会产生Ⅲ型爆发高速飞行的等离子体产生激波时, 会产生Ⅱ型爆发当ＣＭＥｓ 源接近耀斑时, 会触发耀斑爆发     

PROBABLE MAXIMUM FLOOD FOR DAM SAFETY ASSESSMENT

ＰＲＯＢＡＢＬＥＭＡＸＩＭＵＭＦＬＯＯＤＦＯＲＤＡＭＳＡＦＥＴＹＡＳＳＥＳＳＭＥＮＴＣ．Ｆ．ＬＥＥ（Ｆｏｒｍｅｒｌｙ，ＭａｎａｇｅｒｏｆＧｅｏｔｅｃｈｎｉｃａｌａｎｄＨｙｄｒａｕｌｉｃＥｎｇｉｎｅｅｒｉｎｇＤｅｐａｒｔｍｅｎｔ；ＭａｎａｇｅｒｏｆＣｉ...     

MATHEMATICAL MODEL OF OVERLAND FLOW AND MECHANISM OF SOIL CONSERVATION FOR FORESTED STEEP HILLSLOPE－－（II）Mechanism of Soil Conservation Over Steep Hillslope

ＭＡＴＨＥＭＡＴＩＣＡＬＭＯＤＥＬＯＦＯＶＥＲＬＡＮＤＦＬＯＷＡＮＤＭＥＣＨＡＮＩＳＭＯＦＳＯＩＬＣＯＮＳＥＲＶＡＴＩＯＮＦＯＲＦＯＲＥＳＴＥＤＳＴＥＥＰＨＩＬＬＳＬＯＰＥ－－（ＩＩ）ＭｅｃｈａｎｉｓｍｏｆＳｏｉｌＣｏｎｓｅｒｖａｔｉｏｎＯｖｅｒＳｔ...     

MASINGA RESERVOIR IN KENYA：SEDIMENT DISCHARGE AND IMPLICATIONS FOR ITS CAPACITY

ＭＡＳＩＮＧＡＲＥＳＥＲＶＯＩＲＩＮＫＥＮＹＡ：ＳＥＤＩＭＥＮＴＤＩＳＣＨＡＲＧＥＡＮＤＩＭＰＬＩＣＡＴＩＯＮＳＦＯＲＩＴＳＣＡＰＡＣＩＴＹ￥Ｆ．Ａ．Ｏ．Ｏｔｉｅｎｏ（ＳｅｎｉｏｒＬｅｃｔｕｒｅｒｉｎＣｉｖｉｌＥｎｇｉｎｅｅｒｉｎｇ，Ｕｎｉｖｅｒｓｉ...     

THE RIVER CHANNEL ADJUSTMENT AS INFLUENCED BY THE FLOODPLAIN GEOECOSYSTEM： AN EXAMPLE FROM THE HONGSHAN RESERVOIR

ＴＨＥＲＩＶＥＲＣＨＡＮＮＥＬＡＤＪＵＳＴＭＥＮＴＡＳＩＮＦＬＵＥＮＣＥＤＢＹＴＨＥＦＬＯＯＤＰＬＡＩＮＧＥＯＥＣＯＳＹＳＴＥＭ：ＡＮＥＸＡＭＰＬＥＦＲＯＭＴＨＥＨＯＮＧＳＨＡＮＲＥＳＥＲＶＯＩＲ￥ＸＵＪｉｏｎｇｘｉｎ；ＳＨＩＣｈａｎｇｘｉｎｇ（Ｐｒ...     

TOWARDS A NEW APPROACH TO CONSTRUCTING SEDIMENT DISCHARGE RATING CURVES

ＴＯＷＡＲＤＳＡＮＥＷＡＰＰＲＯＡＣＨＴＯＣＯＮＳＴＲＵＣＴＩＮＧＳＥＤＩＭＥＮＴＤＩＳＣＨＡＲＧＥＲＡＴＩＮＧＣＵＲＶＥＳＷｏｌｆｇａｎｇＳＵＭＭＥＲ；ＺＨＡＮＧＷｅｉＡｂｓｔｒａｃｔ：ＴｈｅＳｅｄｉｍｅｎｔＲａｔｉｎｇＣｕｒｖｅ（ＳＲＣ）ｉｓｔｈ...     

太阳质子事件、双带耀斑及日冕物质抛射

本文统计了第２２ 太阳活动周期间（１９９１ ～１９９５ 年） 发生的２５ 个太阳质子事件与太阳耀斑及日冕物质抛射（ＣＭＥ） 事件的关系　　统计结果表明, 所有的太阳质子事件都与耀斑发生相关, 除２ 个质子事件（１９９４１０２０ 和１９９５１０２０ 日发生的太阳质子事件） 与ＣＭＥ发生无关, 其余质子事件也都与ＣＭＥ 相关　　值得注意的是, 与质子事件相关的耀斑有１６ 个是双带耀斑, 其中包括与ＣＭＥ无关的２ 个事件的耀斑, 占总数的６４ ％ 　　上述统计结果证实了无论是太阳耀斑, 还是物质抛射, 它们对太阳质子事件的发生同样起着非常重要的作用     

第23太阳活动周期太阳风参数及地磁指数的统计分析

日冕物质抛射(Coronal Mass Ejection,简称CME)和共转相互作用区(Corotating Interaction Region,简称CIR)是造成日地空间行星际扰动和地磁扰动的两个主要原因,提供了地球磁暴的主要驱动力,进而显著影响地球空间环境.为深入研究太阳风活动及受其主导影响的地磁活动的时间分布特征,本文对大量太阳风参数及地磁活动指数的数据进行了详细分析.首先,采用由NASA OMNIWeb提供的太阳风参数及地磁活动指数的公开数据,通过自主编写matlab程序对第23太阳活动周期(1996-01-01—2008-12-31)的数据包括行星际磁场Bz分量、太阳风速度、太阳风质子密度、太阳风动压等重要太阳风参数及Dst指数、AE指数、Kp指数等主要的地磁指数进行统计分析,建立了包括269个CME事件和456个CIR事件列表的数据库.采用事例分析法和时间序列叠加法分别对两类太阳活动的四个重要太阳风参数(IMF Bz、太阳风速度、太阳风质子密度、太阳风动压)和三个主要地磁指数(Dst、AE、Kp)进行统计分析,并研究了其统计特征.其次,根据Dst指数最小值确定了第23太阳活动周期内的355个孤立地磁暴事件,并以Dst指数最小值为标准将这些磁暴进一步分类为145个弱磁暴、123个中等磁暴、70个强磁暴、12个剧烈磁暴和5个巨大磁暴.最后,采用时间序列叠加法对不同强度磁暴的太阳风参数和地磁指数进行统计分析.统计分析表明,对于CME事件,Nsw/Pdyn(Nsw表示太阳风质子密度,Pdyn表示太阳风动压)线性拟合斜率一般为正;对于CIR事件,Nsw/Pdyn线性拟合斜率一般为负,这可作为辨别CME和CIR事件的一种有效方法.从平均意义上讲,相较于CIR事件,CME事件有更大的南向IMF Bz分量、太阳风动压Pdyn、AE指数、Kp指数以及更小的Dstmin.一般情况下,CME事件有更大的可能性驱动极强地磁暴.总体而言,对于不同强度的地磁暴,Dst指数的变化呈现出一定的相似性,但随着地磁暴强度的增强,Dst指数衰减的速度变快.CME和CIR事件以及其各自驱动的地磁暴事件有着很多不同,因此,需要将CME事件驱动的磁暴及CIR事件驱动的磁暴分开研究.建立CME、CIR事件及地磁暴的数据库以及获取的统计分析结果,将为深入研究地球磁层等离子体片、辐射带及环电流对太阳活动的响应特征提供有利的帮助.     

Energy of coronal mass ejections and large-scale structure of solar magnetic fields

The relationship between variations of the energy and linear velocity of coronal mass ejections (CME) and the typical dimensions of structural elements of the large-scale solar magnetic field structure (LSMFS) is investigated for the period of 1996–2014. It is shown that the maximum linear velocity and maximum energy of CME correspond to the values of the effective solar multipole index n ~ 4.0–4.4. These values determine the maximum size of the complexes of active regions, which, together with the observed maximum values of magnetic field intensity in the complexes, limit the possible maximum CME energy.     

高能质子能谱特征在日冕物质抛射影响预报中的应用

日冕物质抛射(CME)的规模和对地有效性是地磁暴预报中重点关注的特征.本项研究的目的是通过对行星际高能质子通量和能谱的特征与演化规律的分析,得到CME对粒子的加速能力,评估CME可能对地磁场造成的影响.在工作中,统计分析了ACE/EPAM的1998-2010年的质子数据,对质子能谱进行了拟合,得到了能谱指数,并对能谱指数及其变化特征所对应的CME和地磁暴进行了相关统计.通过研究发现:(1)能谱指数随着太阳活动水平而变化,高年最大,达到-2.6,而且涨落幅度也达到±0.4,而在太阳活动低年则稳定在-3.0左右;(2)CME对粒子的加速对应着能谱指数的升高,幅度达到20%时,CME引起地磁暴的可能性较大;(3)冕洞高速流到达地球时,高能质子通量也会升高,但能谱指数同时会有下降;(4)以2004年全年的能谱指数为例,对能谱指数在地磁暴预报中的应用进行了评估,结论认为,能谱指数的升高是CME引发地磁暴的必要条件,可以作为地磁暴预报的参数使用.     

Relativistic electron losses related to EMIC waves during CIR and CME storms

The losses of radiation belt electrons to the atmosphere due to wave–particle interactions with electromagnetic ion-cyclotron (EMIC) waves during corotating interaction region (CIR) storms compared to coronal mass ejections (CME) storms is investigated. Geomagnetic storms with extended ‘recovery’ phases due to large-amplitude Alfvén waves in the solar wind are associated with relativistic electron flux enhancements in the outer radiation belt. The corotating solar wind streams following a CIR in the solar wind contain large-amplitude Alfvén waves, but also some CME storms with high-speed solar wind can have large-amplitude Alfvén waves and extended ‘recovery’ phases. During both CIR and CME storms the ring current protons are enhanced. In the anisotropic proton zone the protons are unstable for EMIC wave growth. Atmospheric losses of relativistic electrons due to weak to moderate pitch angle scattering by EMIC waves is observed inside the whole anisotropic proton zone. During storms with extended ‘recovery’ phases we observe higher atmospheric loss of relativistic electrons than in storms with fast recovery phases. As the EMIC waves exist in storms with both extended and short recovery phases, the increased loss of relativistic electrons reflects the enhanced source of relativistic electrons in the radiation belt during extended recovery phase storms. The region with the most unstable protons and intense EMIC wave generation, seen as a narrow spike in the proton precipitation, is spatially coincident with the largest loss of relativistic electrons. This region can be observed at all MLTs and is closely connected with the spatial shape of the plasmapause as revealed by simultaneous observations by the IMAGE and the NOAA spacecraft. The observations in and near the atmospheric loss cone show that the CIR and CME storms with extended ‘recovery’ phases produce high atmospheric losses of relativistic electrons, as these storms accelerate electrons to relativistic energies. The CME storm with short recovery phase gives low losses of relativistic electrons due to a reduced level of relativistic electrons in the radiation belt.     

Changes in the solar magnetic field preceding a coronal mass ejection

The combined observing power of the Yohkoh, SOHO and TRACE spacecraft, along with the continuing ground-based observations has proved invaluable for the detection of changes in the magnetic morphology preceding coronal mass ejections (CMEs). A wide range of activity from small scale dimmings to large scale eruptions covering half the solar disk have been observed. The relationship between flares and CMEs has also become clearer. Rather than one event causing the other it would seem that it is a global change in the magnetic field which causes both. Recently, there has been a lot of interest in the sigmoid (S-shaped) structures seen in soft X-rays. The likelihood of a CME occurring appears to increase if there is a sigmoidal structure observed. This has formed the basis of more extensive studies into predicting the time and location of a CME from the changes in behaviour of features on the solar disk.     

对自相似扩展(SSE)模型的改进和研究

自相似扩展拟合法(Self-Similar Expansion,SSE)假设日冕物质抛射(CME)具有恒定角宽度、沿径向向外传播的、自相似扩展的球形前沿,由日心出发的、与这个球形前沿相切的圆锥的圆锥角就是通常所说的CME角宽度,半角宽度取值范围是[0°,90°],固定Φ角拟合法(Fixed-Φ,FΦ)和调和均值拟合法(Harmonic-mean,HM)分别对应SSE模型的半角宽度为0°和90°的特殊情况.本文中修改后的自相似扩展拟合法(MSSE)假设CME具有自相似扩展的半球形前沿,能够提取的CME参数包括由日心出发的、圆锥截面过球心的圆锥的半圆锥角和CME的主传播方向、传播速度,其中半圆锥角取值范围是[0°,90°],FΦ和HM分别对应MSSE模型的半圆锥角为0°和45°的特殊情况,半圆锥角为90°时,CME前沿是以日心为圆心的半圆.MSSE拟合法扩大了SSE模型对CME前沿形态的描述范围,将半圆锥角作为判断CME是否能够到达、何时到达某颗卫星的重要参数.基于单颗STEREO卫星日球层成像仪(Heliospheric Imager,HI)图像,结合STEREO和ACE卫星的太阳风实地观测数据,本文深入分析了2010年23个CME事件,结果发现:在用于预报CME事件是否能到达某颗卫星、何时到达时,MSSE拟合法相比FΦ、HM和SSE拟合法,不但可以更准确地拟合CME主传播方向和传播速度,也可以缩小预计到达时间和到达速度的误差.     

Solar connections of geoeffective magnetic structures

Coronal mass ejections (CMEs) and high-speed solar wind streams (HSS) are two solar phenomena that produce large-scale structures in the interplanetary (IP) medium. CMEs evolve into interplanetary CMEs (ICMEs) and the HSS result in corotating interaction regions (CIRs) when they interact with preceding slow solar wind. This paper summarizes the properties of these structures and describes their geoeffectiveness. The primary focus is on the intense storms of solar cycle 23 because this is the first solar cycle during which simultaneous, extensive, and uniform data on solar, IP, and geospace phenomena exist. After presenting illustrative examples of coronal holes and CMEs, I discuss the internal structure of ICMEs, in particular the magnetic clouds (MCs). I then discuss how the magnetic field and speed correlate in the sheath and cloud portions of ICMEs. CME speed measured near the Sun also has significant correlations with the speed and magnetic field strengths measured at 1 AU. The dependence of storm intensity on MC, sheath, and CME properties is discussed pointing to the close connection between solar and IP phenomena. I compare the delay time between MC arrival at 1 AU and the peak time of storms for the cloud and sheath portions and show that the internal structure of MCs leads to the variations in the observed delay times. Finally, we examine the variation of solar-source latitudes of IP structures as a function of the solar cycle and find that they have to be very close to the disk center.     

Origin and structures of solar eruptions I: Magnetic flux rope

Coronal mass ejections (CMEs) and solar flares are the large-scale and most energetic eruptive phenomena in our solar system and able to release a large quantity of plasma and magnetic flux from the solar atmosphere into the solar wind. When these high-speed magnetized plasmas along with the energetic particles arrive at the Earth, they may interact with the magnetosphere and ionosphere, and seriously affect the safety of human high-tech activities in outer space. The travel time of a CME to 1 AU is about 1–3 days, while energetic particles from the eruptions arrive even earlier. An efficient forecast of these phenomena therefore requires a clear detection of CMEs/flares at the stage as early as possible. To estimate the possibility of an eruption leading to a CME/flare, we need to elucidate some fundamental but elusive processes including in particular the origin and structures of CMEs/flares. Understanding these processes can not only improve the prediction of the occurrence of CMEs/flares and their effects on geospace and the heliosphere but also help understand the mass ejections and flares on other solar-type stars. The main purpose of this review is to address the origin and early structures of CMEs/flares, from multi-wavelength observational perspective. First of all, we start with the ongoing debate of whether the pre-eruptive configuration, i.e., a helical magnetic flux rope (MFR), of CMEs/flares exists before the eruption and then emphatically introduce observational manifestations of the MFR. Secondly, we elaborate on the possible formation mechanisms of the MFR through distinct ways. Thirdly, we discuss the initiation of the MFR and associated dynamics during its evolution toward the CME/flare. Finally, we come to some conclusions and put forward some prospects in the future.     

基于多视角观测的SEP事件与twin-CME关系研究

本文联合SOHO和STEREO-A/B（三视角）日冕观测和太阳高能粒子（SEP）观测,分析了2007—2014年间169个快速（速度>900 km·s^-1）、宽角度（>60°）日冕物质抛射（CME）及其先行CME和关联SEP事件.通过相关分析,给出了SOHO/EPHIN 25~53MeV及STEREO/HET 23.8~60 MeV能量范围的大SEP事件通量判断阈值,分别为0.01和0.014（cm²·s·sr·MeV）^-1.三视角CME观测能有效地避免投影效应产生的twin-CME事件误判,统计得到单一视角确定twin-CME事件的误判率一般低于10%,最高不超过15%.基于三视角判断的twin-CME事件及SEP事件峰值强度,得到判断twin-CME事件的时间阈值最短约为9 h（9~13 h）.single-CME产生的SEP事件强度与CME速度、动能的相关性明显高于twin-CME,并且三视角下的相关性结果与单视角类似.结果表明,一个主CME可能存在多个先行CME,依据单卫星观测判断先行CME时有一定的误判几率,但少数单个先行CME的误判并不影响基于单卫星的统计规律或统计结果.