Title: Pinching of ICME Flux Rope: Unprecedented Multipoint Observations of Internal Magnetic Reconnection during Gannon's Superstorm Show Chinese title

Title: ICME通量绳的夹紧：加农超级风暴期间内部磁重联的前所未有的多点观测

Abstract: The extreme solar storm of May 10, 2024, during the 25th solar cycle, which recorded a symmetric H component index (Sym-H) reaching -500 nT, was the strongest since the 2003 Halloween storm. This event offered a unique opportunity for unprecedented multipoint observation of the complex interaction of Interplanetary Coronal Mass Ejections (ICME) from different vantage points. Utilizing NASA's Wind, ACE, DSCOVR, THEMIS-C, STEREO-A, MMS, and ISRO's recently launched Aditya-L1 spacecraft, we comprehensively investigated the spatio-temporal variations in interplanetary plasma and magnetic field parameters. Our study reveals large-scale quasi-steady magnetic reconnection within the interior of the ICME flux rope, possibly triggered by interactions between multiple ICMEs. A current sheet (CS) forms within the flux rope, enabling internal magnetic reconnection between concentric magnetic surfaces, which leads to a sharp reversal of the IMF By component, as observed at the L1 point. Concurrently, reconnection exhaust and enhanced electron and ion fluxes were detected with the CS, extending over 200 RE (1.3 million km) along the GSE-y direction. This finding sheds new light on the role of internal reconnection in ICME evolution, highlighting its pivotal role in modifying the morphology of the ICME magnetic structure and exerting severe space weather effects on Earth. Show Chinese abstract

Abstract: 2024年5月10日的极端太阳风暴发生在第25个太阳周期，记录到对称H分量指数（Sym-H）达到-500 nT，这是自2003年万圣节风暴以来最强的。 这一事件为从不同观测点进行前所未有的行星际日冕物质抛射（ICME）复杂相互作用的多点观测提供了独特的机会。 利用NASA的Wind、ACE、DSCOVR、THEMIS-C、STEREO-A、MMS以及印度空间研究组织最近发射的Aditya-L1航天器，我们全面研究了行星际等离子体和磁场参数的时空变化。 我们的研究揭示了ICME通量绳内部的大尺度准稳态磁重联，可能是由多个ICME之间的相互作用引发的。 在通量绳内部形成一个电流片（CS），使得同心磁面之间的内部磁重联得以发生，导致IMF By分量的急剧反转，如在L1点观测到的那样。 同时，在CS处检测到重联排气以及增强的电子和离子通量，沿着GSE-y方向延伸超过200 RE（130万公里）。 这一发现为内部重联在ICME演化中的作用提供了新的见解，突显了其在改变ICME磁场结构形态和对地球产生严重空间天气效应中的关键作用。