Solar Orbiter: Studies of the Solar Wind Charged Particle Populations

UCL/MSSL是一个国际联合体的主要研究者（PI）研究所，为欧空局太阳轨道器使命提供太阳风分析仪仪器套件（SWA）。利用3个科学传感器，SWA能够在距离太阳0.28 Au以下的不同距离（即太阳到地球距离的四分之一左右）和太阳高纬度地区对电子、质子、α粒子和重离子总数进行采样。特别是，UCL/MSSL为SWA套件设计和建造了电子分析仪系统（EAS）。SWA在法国、意大利和美国的合作伙伴为该套件提供了重离子传感器（HIS）和质子-α传感器（PAS）。此外，MSSL在航天器上的EUI仪器中发挥着重要作用，该仪器由一套观测太阳大气层的成像望远镜组成。EUI将使我们能够确定太阳日冕的全球结构，并提供动态太阳大气中精细尺度过程的重要理解。EUI拍摄的图像提供了太阳表面和外日冕之间不可或缺的联系，最终塑造了SWA和太阳轨道器上其他仪器原位采样的行星际介质的特征。使命于2020年2月11日发射，目前处于巡航阶段，预计2021年底将开始名义上的使命。虽然EUI和其他遥感数据在名义使命开始之前不会定期获取，但SWA巡航阶段数据已经可用，因此代表了一个重要的新数据集，可以立即支持从2021年9月开始的博士课程分析。特别是，我们的目标是使用巡航阶段的测量从3 SWA传感器进行研究的性质的太阳风粒子群及其变化。例如，太阳风电子总数一般由3个组成部分组成，它们共同包含有关太阳源区发生的过程、采样等离子体返回太阳的磁连接以及可能发生在太阳风本身内的等离子体过程（例如湍流、波粒相互作用和磁重连）的信息。分离这些过程的影响是一项复杂的任务，需要高节奏，高分辨率的数据类型，将可从SWA EAS。作为这个博士课程的启动项目，我们将寻求分析行星际冲击通道周围的高分辨率数据的“捕获模式”捕获，这些冲击是由许多形式的太阳活动（例如，CME喷发，共同旋转的相互作用区域）通过太阳风驱动的。进一步进入该项目，我们将寻求制定一项研究计划，从名义阶段开始，利用MSSL参与SWA和EUI，以支持太阳-太阳风联系的研究，这代表了使命的主要目标。例如，上述通过太阳风驱动冲击的活动形式是EUI的主要目标。因此，将冲击的性质和性质与各种驱动因素的性质联系起来，很好地说明了我们将寻求通过太阳轨道器的联合观测进行的一些潜在研究。此外，该项目将受益于其他任务的数据，如美国宇航局的帕克太阳探测器，我们将使用它来进行协调研究。该项目的结果将增加整个欧空局太阳轨道器计划的成功，学生将成为MSSL科学和科学规划团队的一个组成部分。学生将与我们在欧洲和美国的合作伙伴合作，他们为SWA套件和EUI的其他主要子系统提供了HIS和PAS传感器。这个项目将使学生处于一个良好的位置，更普遍地合作，并找到未来的位置，例如在国际太阳轨道器社区。

UCL/MSSL is the Principal Investigator (PI) Institute on an international consortium providing the Solar Wind Analyser suite (SWA) of instruments for the ESA Solar Orbiter mission. Using 3 scientific sensors, SWA is able to sample electron, proton, alpha particle and heavy ion populations at various distances down to 0.28 AU from the Sun (i.e. around a quarter the distance from the Sun to the Earth) and at high solar latitudes. In particular, UCL/MSSL has designed and built the Electron Analyser System (EAS) for the SWA suite. SWA partners in France, Italy and the USA have provided the Heavy Ion Sensor (HIS) and Proton-Alpha Sensor (PAS) for the suite. In addition, MSSL has a major role in the EUI instrument on the spacecraft, which consists of a suite of imaging telescopes to observe the solar atmosphere. EUI will allow us to determine the global structure of the solar corona and to provide a crucial understanding of fine scale processes in the dynamic solar atmosphere. Images taken by EUI offer an indispensable link between the solar surface and the outer corona, which ultimately shapes the characteristics of the interplanetary medium sampled in situ by SWA and other instruments on Solar Orbiter.The mission was launched on 11th Feb 2020, and is now in cruise phase ahead of a nominal mission start in late 2021. Although EUI and other remote sensing data will not be regularly taken until the nominal mission starts, SWA cruise phase data is already available, and thus represents an important new data set that could immediately support analysis within this PhD program starting in September 2021. In particular, we aim to use cruise-phase measurements from the 3 SWA sensors to undertake studies of the nature of the solar wind particle populations and their variability. For example, the solar wind electron population in general consists of 3 components which together contain information about the processes occurring at the source region on the Sun, the magnetic connections of the sampled plasma back to the Sun and on the plasma processes (e.g. turbulence, wave-particle interactions and magnetic reconnection) which may be occurring within the solar wind itself. Separating the effects of these processes is a complicated task requiring high-cadence, high resolution data of the type that will be available from SWA EAS. As a kick-off project on this PhD program, we will seek to analyse 'trigger-mode' captures of high resolution data around the passage of interplanetary shocks, which are driven through the solar wind by many forms of solar activity (for example, CME eruption, co-rotating interaction regions). Further into the project, we will seek to develop a research plan which would make use, from the start of the nominal phase, of the MSSL involvement in both SWA and EUI to support studies of the Sun-solar wind connections, which represent the headline goals of the mission. For example, the forms of activity mentioned above which drive shocks through the solar wind are prime targets for EUI. Thus linking the properties and nature of the shock to the properties of the various drivers is a good illustration of a number of potential studies that we will seek to pursue with the combined Solar Orbiter observations. In addition, the project will benefit from the availability of data from other missions, such as NASA's Parker Solar Probe, which we will use to undertake coordinated studies.The results this project will add to the success of the overall ESA Solar Orbiter program, and the student will be an integral part of the MSSL science and science-planning teams. The student will collaborate with our partners in Europe and the USA, who have provided the HIS and PAS sensors for the SWA suite and other major subsystems for EUI. This project will place the student in a good position to collaborate more generally and to find future positions e.g. within the international Solar Orbiter community.