Solar Orbiter: Studies of the Solar Wind Charged Particle Populations

UCL/MSSL是一个国际财团的首席研究员(PI)研究所，该财团为欧空局太阳轨道飞行器飞行任务提供太阳风分析仪套件(SWA)。使用3个科学传感器，SWA能够对距离太阳不同距离的电子、质子、阿尔法粒子和重离子种群进行采样，范围从太阳到地球的0.28 AU(即从太阳到地球的距离的大约四分之一)和高太阳纬度。特别是，UCL/MSSL为SWA套件设计和建造了电子分析系统(EAS)。SWA在法国、意大利和美国的合作伙伴已经为该套件提供了重离子传感器(HIS)和质子-阿尔法传感器(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的成像望远镜组成。EUI将使我们能够确定日冕的全球结构，并提供对动态太阳大气中精细尺度过程的关键理解。EUI拍摄的图像在太阳表面和外冕之间提供了不可或缺的联系，最终塑造了由SWA和其他太阳轨道上的仪器现场采样的行星际介质的特征。任务于2020年2月11日发射，目前处于巡航阶段，名义上的任务将于2021年底开始。虽然EUI和其他遥感数据在名义任务开始之前不会定期获取，但SWA巡航阶段数据已经可用，因此代表着一个重要的新数据集，可以立即支持从2021年9月开始的这一博士项目的分析。特别是，我们的目标是使用来自3个SWA传感器的巡航相位测量来开展太阳风粒子种群的性质及其变异性的研究。例如，太阳风电子总数一般由3个分量组成，这3个分量共同包含有关太阳源区域发生的过程、采样等离子体返回太阳的磁连接以及太阳风本身内可能发生的等离子体过程(例如湍流、波粒相互作用和磁重联)的信息。分离这些过程的影响是一项复杂的任务，需要从SWA EAS获得的那种高节奏、高分辨率的数据。作为该PHD项目的一个启动项目，我们将寻求分析围绕行星际激波通过的高分辨率数据的触发模式捕获，这些激波是由多种形式的太阳活动(例如，CME喷发、共同旋转的相互作用区)通过太阳风驱动的。在该项目的进一步推进中，我们将寻求制定一项研究计划，从名义阶段开始，利用MSL对SWA和EUI的参与，支持对太阳-太阳风连接的研究，这是这次飞行任务的主要目标。例如，上面提到的通过太阳风驱动激波的活动形式是EUI的主要目标。因此，将激波的性质和性质与各种驱动因素的性质联系起来，是我们将寻求通过太阳轨道组合观测进行的一些潜在研究的很好例证。此外，该项目将受益于来自其他任务的数据，如NASA的帕克太阳探测器，我们将利用这些数据进行协调研究。该项目的结果将增加整个欧空局太阳轨道器计划的成功，该学生将成为MSSL科学和科学规划团队不可或缺的一部分。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很好的位置来进行更广泛的合作，并找到未来的职位，例如在国际太阳轨道飞行器社区内。

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.