Study of solar wind discontinuities, their evolution, transport and impact on the near-Earth environment.

这个CASE学生奖学金的目标是解决长期存在的问题，即日冕物质抛射（CME）形式的太阳爆发和持续高速太阳风区域导致行星际冲击，共转相互作用区域（CIR），与太阳系天体相互作用。该项目的目的是研究太阳风间断的质量、能量和动量、其传输特性及其对近地系统的影响。这将利用目前从SOHO和STEREO飞行任务获得的一套独特的日光层监测数据。利用ACE和Wind航天器在L1处对太阳风进行上游监测，将提供本地化的原位诊断。由四个航天器组成的集群使命将在太阳风驱动器与其对近地系统的影响之间提供独特的联系，这些影响由地面仪器测量，包括EISCAT和SuperDARN。特别是，该项目将调查：1）静风的影响：由于日光层等离子体片中分离的等离子体团，太阳风中的不连续性对磁层的影响是未知的。STEREO将允许第一次详细绘制靠近太阳的这些结构，那里的太阳风密度最高。利用Cluster航天器以及WIND和ACE航天器对这些结构进行多点研究（平面定向、不连续性诊断）将有助于对这些结构的演变进行详细分析。对不连续性对磁层的影响进行系统分析，将有助于更好地了解磁层活动的静时驱动因素。2)瞬态研究：利用HI照相机和1个Au航天器阵列（Cluster、ACE、WIND）将首次有可能研究日冕物质抛射的二维结构。通量管的方向CME的前面，里面和后面将比较CME的径向密度演变。HI相机将用于确定我们在瞬变前部的位置，并了解静止时间行星际通量管如何被压缩并在瞬变之前滑动。3)瞬变效应：直接观察的2-D结构的瞬变和他们的披覆在地球的磁层，因为他们与弓激波相互作用将是第一次详细分析的机制，确定的“地球效应”的太阳风扰动的磁层。将使用与ACE、双星星星、EISCAT和SuperDARN相结合的Cluster航天器来研究磁层对HI照相机中看到的单个密度波动和撞击结构内湍流的响应。根据这些活动的进展情况，工作可能扩大到：（一）解释太阳风与具有内在磁场的太阳系天体（如近地和土星系统）和非磁化天体（如金星、火星和彗星）之间相互作用的差异。这将是在参与机构内已在进行的一些初步工作的基础上进行的。㈡开发必要的理论模型，以展示太阳活动对日光层系统的传播、物理过程、相互作用和影响，目的是帮助预测这类活动的影响。

This CASE studentship is targeted at addressing long-standing questions on how the solar eruptions in the form of Coronal Mass Ejections (CMEs) and regions of sustained high speed solar wind resulting in the interplanetary shocks, Corotating Interaction Regions (CIRs), interact with solar system bodies. The aim of the project will be to study the mass, energy and momentum of solar wind discontinuities, their transport characteristics, and their impact on the near-Earth system. This will make use of access to the unique set of heliospheric monitoring data available at this time from the SOHO and STEREO missions. Upstream monitoring of the solar wind at L1 with the ACE and Wind spacecraft will provide localised in-situ diagnostics. The four-spacecraft Cluster mission will provide the unique linkage between the solar wind drivers and their impact on the near-Earth system as measured by ground based instrumentation, including EISCAT and SuperDARN. In particular the project will investigate: 1) Effect of quiet-wind: The effect on the magnetosphere of discontinuities in the solar wind due to detached plasma blobs in the heliospheric plasma sheet is unknown. STEREO will allow the first detailed mapping of these structures close to the Sun where the solar wind density is highest. Multipoint studies of these structures (plane orientation, discontinuity diagnostic) using the Cluster spacecraft as well as the WIND and ACE spacecraft will facilitate detailed analysis of the evolution of these structures. A systematic analysis of the effect of discontinuities on the magnetosphere will lead to a greater understanding of the quiet-time drivers of magnetospheric activity. 2) Study of transients: The study of the 2-D structure of CMEs will for the first time be possible using the HI cameras and the array of 1 AU spacecraft (Cluster, ACE, WIND). The orientation of flux-tubes ahead, inside and behind CMEs will be compared to the radial density evolution of CMEs. The HI cameras will be used to define our location on the front of the transient and to understand how quiet-time interplanetary flux-tubes are compressed and slip ahead of the transient. 3) Effect of transients: Direct observation of the 2-D structure of transients and their draping over the Earth's magnetosphere as they interact with the bow shock will be the first detailed analysis of the mechanisms that determine the 'geo-effectiveness' of solar wind disturbances on the magnetosphere. The Cluster spacecraft combined with ACE, Double Star, EISCAT and SuperDARN will be used to study the response of the magnetosphere to individual density fluctuations seen in the HI cameras and the turbulence within the impinging structure. Depending on the progress of these activities the work may extend to: i) Explaining the differences in the interactions between the solar wind interactions with solar system bodies with intrinsic magnetic field (such as near Earth and Saturnian systems) and those of non-magnetised bodies (such as Venus, Mars and comets). This will follow on from some preliminary work already underway within the participating institutes. ii) Developing the theoretical models necessary to demonstrate the propagation, physical processes, interactions and impact that solar events have on the heliospheric system, with the aim to help in the forecasting of the impact of such events.