Brooks David H, Yardley Stephanie L
College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030, USA.
Mullard Space Science Laboratory, University College London, Holmbury St. Mary, RH5 6NT, UK.
Sci Adv. 2021 Mar 3;7(10). doi: 10.1126/sciadv.abf0068. Print 2021 Mar.
Shock waves associated with fast coronal mass ejections (CMEs) accelerate solar energetic particles (SEPs) in the long duration, gradual events that pose hazards to crewed spaceflight and near-Earth technological assets, but the source of the CME shock-accelerated plasma is still debated. Here, we use multi-messenger observations from the Heliophysics System Observatory to identify plasma confined at the footpoints of the hot, core loops of active region 11944 as the source of major gradual SEP events in January 2014. We show that the elemental composition signature detected spectroscopically at the footpoints explains the measurements made by particle counting techniques near Earth. Our results localize the elemental fractionation process to the top of the chromosphere. The plasma confined closest to that region, where the coronal magnetic field strength is high (a few hundred Gauss), develops the SEP composition signature. This source material is continually released from magnetic confinement and accelerated as SEPs following M-, C-, and X-class flares.
与快速日冕物质抛射（CME）相关的激波在长时间的渐进事件中加速太阳高能粒子（SEP），这些事件对载人航天飞行和近地技术资产构成危害，但CME激波加速等离子体的来源仍存在争议。在这里，我们利用日地物理系统天文台的多信使观测，确定了活跃区域11944热核心环足部的受限等离子体是2014年1月主要渐进SEP事件的来源。我们表明，在足部通过光谱检测到的元素组成特征解释了在地球附近通过粒子计数技术所做的测量。我们的结果将元素分馏过程定位到色球层顶部。最接近该区域（日冕磁场强度较高，几百高斯）受限的等离子体形成了SEP组成特征。这种源物质不断从磁约束中释放出来，并在M级、C级和X级耀斑之后作为SEP被加速。
