Plasma thermodynamics of the inner heliosphere with Solar Orbiter and Parker Solar Probe

天体物理学中最重要的悬而未决的问题之一是：离子和电子是如何在等离子体中变热的，而等离子体实际上没有粒子之间的碰撞？我们可以直接研究加热过程的一种方法是通过测量太阳风来第一手观察天体物理等离子体，太阳风是等离子体从太阳快速热流出的过程。太阳风手有一个有趣的特性，那就是流动中的电子平均比离子热30%。目前尚不清楚这种温差是在太阳风发射到星际空间之前在日冕中产生的，还是由与太阳风本身的湍流消散有关的局部加热过程造成的。无论哪种方式，离子和电子必须与等离子体中的电磁场相互作用才能获得和分配能量。要准确地研究离子、电子和电磁场之间的能量转移机制，需要从理论上理解等离子体动力学和电磁场，并对航天器上的观测数据进行分析。学生将努力回答以下问题：太阳附近的热离子和电子是由什么过程产生的？为什么电子比离子热？太阳风的膨胀如何影响这些加热和加速过程？这名学生将使用新的欧空局太阳轨道器(SO)和美国宇航局帕克太阳探测器(PSP)任务记录的数据来测量与太阳接近的离子、电子和电磁场，这是以前从未研究过的。博士的主要工作将是使用大数据集的统计分析和机器学习或其他大数据分析技术进行数据分析。学生将有机会在国内和国际会议上展示他们的工作，并在领先的科学期刊上发表他们的工作。到博士学位结束时，学生将学会科学写作、数据分析编码、可视化数据的方法、向广大受众展示复杂材料，以及如何管理他们自己的小项目。学生将参加SWA会议，学习为空间科学设计的粒子传感器是如何工作和操作的，并与SO和PSP任务的世界领先科学家合作。

One of the most important unanswered questions in astrophysics is: how do ions and electrons get hot in plasma that effectively has no collisions between particles? One way that we can directly investigate the heating processes is to observe an astrophysical plasma first hand by measuring the solar wind, the hot and fast outflow of plasma from the Sun. The solar wind hand has the interesting property that electrons in the flow are, on average, about 30% hotter than the ions. It is not known whether this difference in temperature is generated in the solar corona before the solar wind is launched into interplanetary space, or caused by local heating processes related to the dissipation of turbulence in the solar wind itself. Either way, the ions and electrons must be interacting with electromagnetic fields in the plasma to gain and distribute energy. To investigate exactly which mechanisms move energy between the ions, electrons, and the electromagnetic fields involves theoretical understanding of kinetic plasma physics and electromagnetism and data analysis of observations taken by spacecraft. The student will work to answer the questions: What processes heat ions and electrons near the Sun? Why are electrons hotter than ions? How does the expansion of the solar wind affect these heating and acceleration processes?The student will use data recorded by the new ESA Solar Orbiter (SO) and NASA Parker Solar Probe (PSP) missions to measure at the ions, electrons and electromagnetic fields closed to the Sun than ever studied before. The primary work of the PhD will be data analysis using statistical analysis of large data sets and machine learning or other big-data analysis techniques.The student will have the opportunity to present their work at national and international conferences and publish work in leading scientific journals. By the end of the PhD, the student will have learned scientific writing, coding for data analysis, methods for visualising data, presenting of complex material to a wide audience, and how to manage their own small projects. The student will participate in SO SWA meetings, learning how particle sensors designed for space science work and are operated, and work with the world-leading scientists of the SO and PSP missions.