Samanta Tanmoy, Tian Hui, Chen Bin, Reeves Katharine K, Cheung Mark C M, Vourlidas Angelos, Banerjee Dipankar
Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030, USA.
Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA.
Innovation (Camb). 2021 Jan 19;2(1):100083. doi: 10.1016/j.xinn.2021.100083. eCollection 2021 Feb 28.
As one of the most spectacular energy release events in the solar system, solar flares are generally powered by magnetic reconnection in the solar corona. As a result of the re-arrangement of magnetic field topology after the reconnection process, a series of new loop-like magnetic structures are often formed and are known as flare loops. A hot diffuse region, consisting of around 5-10 MK plasma, is also observed above the loops and is called a supra-arcade fan. Often, dark, tadpole-like structures are seen to descend through the bright supra-arcade fans. It remains unclear what role these so-called supra-arcade downflows (SADs) play in heating the flaring coronal plasma. Here we show a unique flare observation, where many SADs collide with the flare loops and strongly heat the loops to a temperature of 10-20 MK. Several of these interactions generate clear signatures of quasi-periodic enhancement in the full-Sun-integrated soft X-ray emission, providing an alternative interpretation for quasi-periodic pulsations that are commonly observed during solar and stellar flares.
作为太阳系中最壮观的能量释放事件之一，太阳耀斑通常由日冕中的磁重联提供能量。磁重联过程后磁场拓扑结构重新排列，常常会形成一系列新的环状磁结构，即耀斑环。在耀斑环上方还观测到一个由约500万至1000万开尔文等离子体组成的热弥散区域，称为超拱廊扇区。通常，可以看到黑暗的、蝌蚪状结构穿过明亮的超拱廊扇区。这些所谓的超拱廊向下流（SADs）在加热耀斑日冕等离子体中扮演什么角色仍不清楚。在此我们展示了一次独特的耀斑观测，其中许多SADs与耀斑环碰撞，并将耀斑环强烈加热到1000万至2000万开尔文的温度。其中一些相互作用在全日面积分软X射线发射中产生了准周期增强的清晰特征，为准周期脉动提供了另一种解释，这种脉动在太阳和恒星耀斑期间普遍被观测到。
