标题： 由Metis日冕仪观测到的在HI Ly-α中异常明亮发射的爆发事件 显示英文标题

标题： Eruptive events with exceptionally bright emission in HI Ly-alpha observed by the Metis coronagraph

摘要： Solar轨道器上的日冕仪Metis首次同时提供了紫外线HI赖曼α线的日冕成像以及偏振可见光成像，从而提供了大量关于日冕物质抛射（CME）和太阳爆发性质的信息，包括它们的整体动力学、时间演化、质量含量以及向外膨胀的日冕中的流出速度。 在这项工作中，我们分析了Metis在2021年4月至10月期间观测到的六次CME事件，这些事件的特点是非常强烈的HI赖曼α发射。 我们特别研究了这些事件的形态、运动学、以及发射的时间和径向演化，重点关注最亮的紫外线特征。 通过确定Metis天球平面上最亮部分的高度-时间曲线，我们研究了所考虑的爆发事件的动力学。 此外，通过利用来自两个其他日冕仪的共时图像——SOHO上的LASCO/C2和STEREO-A上的COR2，我们确定了CMEs在日球层中的三维位置。 最后，对明亮紫外线特征的辐射校准Metis图像进行了分析，以估算它们的体积和密度。 从运动学和辐射分析中，我们得到了这些事件明亮紫外线核心温度的指示。 对这些与日冕物质抛射相关的强紫外线发射特征的分析表明，当前的空间日冕仪星座——Metis、LASCO/C2和COR2，在提供从起源到数个太阳半径传播阶段的爆发事件结构和动力学完整表征方面的能力。 此外，我们展示了Metis仪器的独特能力，即同时观测HI赖曼α线和偏振可见光辐射，允许对这些事件的热状态进行等离子体诊断。 显示英文摘要

摘要： Metis, the coronagraph on board Solar Orbiter, provides for the first time coronagraphic imaging in the ultraviolet HI Ly-alpha line and, simultaneously, in polarized visible light, thus providing a host of information on the properties of CMEs and solar eruptions like their overall dynamics, time evolution, mass content, and outflow propagation velocity in the expanding corona. We analyzed in this work six CMEs observed by Metis between April and October 2021, which are characterized by a very strong HI Ly-alpha emission. We studied in particular the morphology, kinematics, and the temporal and radial evolution of the emission of such events, focusing on the brightest UV features. The kinematics of the eruptive events under consideration were studied by determining the height-time profiles of the brightest parts on the Metis plane of the sky. Furthermore, the 3D position in the heliosphere of the CMEs were determined by employing co-temporal images from two other coronagraphs: LASCO/C2 onboard SOHO, and COR2 onboard STEREO-A. Finally, the radiometrically calibrated Metis images of the bright UV features were analyzed to provide estimates of their volume and density. From the kinematics and radiometric analyses, we obtained indications of the temperatures of the bright UV cores of these events. The analysis of these strong UV-emitting features associated with coronal mass ejections demonstrates the capabilities of the current constellation of space coronagraphs, Metis, LASCO/C2, and COR2, in providing a complete characterization of the structure and dynamics of eruptive events in their propagation phase from their inception up to several solar radii. Furthermore, we show how the unique capabilities of the Metis instrument to observe these events in both HI Ly-alpha line and polarized VL radiation allow plasma diagnostics on the thermal state of these events.