Energetic Ions and Electrons in Solar Jets

恒星耀斑中的离子和电子加速现象在宇宙中普遍存在，然而，我们的太阳是唯一一个可以同时观测到高能粒子和它们的源耀斑的天体。太阳耀斑的加速机制，极大地增强了（高达一万倍）稀有元素，如3 He和超重核（如197 Au和207 Pb），已经困扰了近50年，并提出了天体物理学中最极端的分馏例子之一。测得的重离子增强，增加离子质量，与最强的增强发生冲突的低质量的3 He元素，表明一个以上的机制参与离子加速。与逃逸的高能粒子相关的耀斑通常以喷流的形式被观察到，这意味着磁重联包括向行星际空间开放的磁力线。该项目旨在促进我们对太阳耀斑中离子增强机制的理解，首次解决高能离子和电子与其太阳源之间的关联。具体而言，该项目解决了1）与只有一种粒子成分占主导地位的来源相比，在具有共同离子和电子检测的事件中太阳源有多大不同，以及2）在何种程度上是注入/传输到行星际空间导致缺乏离子或电子检测。目标1）将通过将喷流结构和底层磁场的前所未有的高分辨率成像观测与高能离子和电子的原位观测特性相关联来解决。目标2）将通过将注入延迟（在低能量电子和高能量电子之间以及在电子和离子之间）与太阳能源特性相关联来解决。

Acceleration of ions and electrons in stellar flares is ubiquitous in the universe, however, our Sun is the only astrophysical object where energetic particles and their source flares can be jointly observed. The acceleration mechanism in solar flares, tremendously enhancing (up to factors of ten thousand) rare elements like 3He and ultra-heavy nuclei (like 197Au and 207Pb), has been puzzling for almost 50 years and presents one of the most extreme fractionation examples in astrophysics. The measured heavy-ion enhancement, increasing with ion mass, conflicts with the strongest enhancement which occurs for low-mass 3He element indicating that more than one mechanism is involved in the ion acceleration. Flares associated with escaping energetic particles have been commonly observed in jet-like forms, implying magnetic reconnection comprising field lines open to interplanetary space. This project aims to advance our understanding of the ion enhancement mechanisms operating in solar flares addressing for the first time the association between the energetic ions and electrons and their solar sources. Specifically, the project resolves 1) how different are solar sources in events with a common ion and electron detection compared to sources where only one particle component is dominant, and 2) to what extent is the injection/transport to/in interplanetary space responsible for lack of ion or electron detection. The objective 1) will be addressed by relating unprecedented high-resolution imaging observations of the jet structure and underlying magnetic fields with the in-situ observed properties of energetic ions and electrons. The objective 2) will be addressed by relating injection delays (between the low and high energy electrons and between electrons and ions) with solar source characteristics.