Studies of charged particle populations in the solar wind using Solar Orbiter SWA data.

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将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，低至0.28 AU(即从太阳到地球的距离约为四分之一)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)。该任务目前计划于2020年2月发射，2020年10月备用。SWA数据将在启动后的几周内提供，因此，对这一新数据集的分析可以在该博士项目的第一年内开始。特别是，我们的目标是使用来自SWA的3个传感器的巡航相位测量来开展太阳风粒子种群的性质、它们的可变性及其与太阳的联系的研究。在博士学位开始和发射之间(希望很短)，我们将利用以前任务的数据进行背景/预备研究。许多潜在的研究项目属于任务科学计划的范围(例如，在由PI‘s和ESA生成的https://issues.cosmos.esa.int/solarorbiterwiki/display/SOSP/SAP-related+work任务“科学活动计划”中详细说明)，因此将在资助期间开始时根据学生的具体背景和兴趣确定具体的初始项目。例如，已知太阳风电子总数一般由3个组成部分组成：近各向同性的最冷电子的“核”群--可在任何方向探测到给定能量的大致相同通量的电子；“晕”群的能量较高，并且相对于核心显示平均速度略有变化，从而在太阳风中提供“热通量”；最后，“Strahl”群通常被视为沿磁场流动的能量更高的粒子束。这些不同的电子群合在一起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。作为这里可能进行的那种科学研究的另一个例子，该学生可能会研究星际冲击的全球驱动因素和局部性质。激波和其他波锋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。这些激波锋将通过在SWA和其他现场仪器上执行触发模式通过航天器时被捕捉到前所未有的详细信息。这些项目的结果对整个欧空局太阳轨道计划的成功至关重要，因此该学生也将成为MSL科学和科学规划团队不可或缺的一部分。学生还将有机会与我们在法国、意大利和美国的合作伙伴合作，他们为SWA套件提供了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 will 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.The mission is currently baselined for launch in Feb 2020, with a back-up in October 2020. SWA data will be available within a few weeks of the launch, and thus analysis of this new data set can begin within the first year of this PhD program. 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, their variability and their links to the Sun. In the (hopefully short) period between the start of the PhD and launch we will undertake background/ preparatory studies using data from previous missions.Many potential research projects fall within the scope of the mission science plan (as detailed, for example, in the mission 'Science Activity Plan' at https://issues.cosmos.esa.int/solarorbiterwiki/display/SOSP/SAP-related+work generated by the PI's and ESA) and so a specific initial project will be identified at the start of the funded period according to the specific background and interests of the student. As a possible example, it is known that the solar wind electron population in general consists of 3 components: A 'core' population of the coldest electrons which is nearly isotropic - approximately the same flux of electrons of a given energy may be detected in any direction; A 'halo' population occurs at somewhat higher energies, and shows a slight shift in average velocity with respect to the core, and thus provides a 'heat flux' in the solar wind; Finally, a 'strahl' population is often seen as a more energetic beam of particles streaming along the magnetic field. Together these different electron populations 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 further example of the kind of scientific research possible here, the student might undertake studies of both the global drivers and local properties of interplanetary shocks. Shocks and other wave fronts are driven through the solar wind by many forms of solar activity (for example, CME eruption, co-rotating interaction regions). These shock fronts will be captured in unprecedented detail as they pass the spacecraft by the execution of a trigger mode on SWA and other in situ instruments.The results of such projects are critical to the success of the overall ESA Solar Orbiter program, and the student will thus also be an integral part of the MSSL science and science-planning team. The student will also have the opportunity to collaborate with our partners in France, Italy and the USA, who have provided the HIS and PAS sensors for the SWA suite. This project will place the student in a good position to collaborate more generally and to find future positions e.g. within the Solar Orbiter community internationally.