ASO-S卫星工程LST爆发模式触发和终止方案

The Trigger and Termination Scheme for the Event Mode of the Lyman-alpha Solar Telescope(LST)Onboard the ASO-S Mission

先进天基太阳天文台(ASO-S)是计划于2021年底或2022年上半年发射的中国首颗综合性太阳探测卫星,莱曼阿尔法太阳望远镜(LST)作为ASO-S的有效载荷之一,具体包括莱曼阿尔法全日面成像仪(SDI)、日冕仪(SCI)以及白光望远镜(WST)3台科学仪器和2台导行镜(GT),其主要目标是在多个波段对太阳上的两类剧烈爆发现象(太阳耀斑和日冕物质抛射)进行连续不间断的高分辨率观测.为了实现这一观测目标,LST所有仪器的观测模式中均包含了一种针对爆发事件而设置的爆发模式.该模式下,SCI将以更高的频率进行图像采集,SDI和WST则以更高的频率对爆发所在区域进行图像采集.测试结果表明,观测图像经过中值滤波、像元合并处理后,可以通过监测图像各像元亮度的相对变化提取爆发事件的时间和位置信息.这些信息将为LST观测模式间的相互切换提供重要电子学输入.

The Advanced Space-based Solar Observatory(ASO-S)is the China’sfirst comprehensive solar dedicated satellite,scheduled to be launched around 2022.The Lyman-alpha(Lyα)Solar Telescope(LST)is one of the payloads of the ASO-S,consisting of three scientific instruments and two Guide Telescopes(GTs).The scientific instruments include a Solar Disk Imager(SDI),a White-light Solar Telescope(WST)and a Solar Corona Imager(SCI),which are aimed to observe the whole evolving process of various eruptions on the Sun,including solar flares and coronal mass ejections,in multiwavelengths with high temporal and spatial resolutions.To achieve this goal,all the three instruments have an observation mode dedicated to the event observations,called the event mode.In this mode,the SCI takes full-frame coronal images at a higher cadence,while SDI and WST take partial frame images around the eruption region at a higher cadence.The time and location information of the eruption events can be effectively obtained by monitoring the relative changes of brightness of each pixel after the median filtering and rebinning the onboard images.The obtained information will provide an important electronic input for the automatic switching between different observation modes of LST.