日珥爆发期间的日冕绿线辐射：其与EUV晚相相对应的光谱证据
Coronal Green-Line Emission During a Solar Prominence Eruption: Spectroscopic Evidence of Its Correspondence with the EUV Late Phase
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中文总结 AI 辅助
本研究通过Aditya-L1的VELC光谱观测，发现日珥爆发中5303 Å绿线辐射与EUV晚相相对应，线宽减小表明其源于等离子体冷却，为ELP起源提供首个空间光谱证据。
中文摘要 AI 辅助
我们报告了2025年10月9日太阳西边缘一次日珥爆发期间的光谱观测，该事件与一次于12:11 UT开始的M2.0级耀斑相关。此次事件由Aditya-L1卫星上的可见发射线日冕仪（VELC）以凝视模式捕获，提供了Fe XIV 5303 Å日冕绿线的连续观测。空间平均的绿线辐射与多个SDO/AIA通道中观测到的EUV晚相（ELP）辐射表现出清晰的对应关系。特别地，在15:24 UT出现的增强的5303 Å发射峰值与AIA 211、171、193和335 Å波段的次级峰值同时发生，出现在X射线峰值之后约173分钟。5303 Å线宽信息为ELP的机制提供了重要约束。线宽在ELP峰值前逐渐减小约28%，与耀斑后日冕环的冷却大体一致。这种行为表明ELP主要与等离子体冷却相关，磁重联提供的额外能量输入相对较弱，未产生显著的线宽增强。估算的非热速度从脉冲相期间的约36 km/s降至渐变相期间的约21 km/s，表明湍流等离子体运动减弱。多普勒速度从爆发上升阶段以正值为主演变为后期渐变阶段的负值，暗示了等离子体先向上后向下的运动。据我们所知，这项研究提供了首个基于空间的光谱证据，将日冕绿线辐射与ELP及其在太阳耀斑期间的起源联系起来。
英文摘要
We report spectroscopic observations during a prominence eruption on 9 October 2025 from the Sun's west limb, associated with an M2.0 flare that commenced at 12:11 UT. The event was captured in sit-and-stare mode by the Visible Emission Line Coronagraph (VELC) onboard Aditya-L1, providing continuous observations of the Fe XIV 5303 Åcoronal greenline. The spatially averaged green-line emission exhibits a clear correspondence with the EUV late-phase (ELP) emission observed in multiple SDO/AIA channels. In particular, an enhanced 5303 Åemission peak at 15:24 UT coincides with secondary peaks in the AIA 211, 171, 193, and 335 Åpassbands, occurring $\sim173$ minutes after the X-ray peak. The 5303 Åline-width information provides important constraints on the mechanism responsible for the ELP. The line-width decreases progressively by about 28\% toward the ELP peak, broadly consistent with the cooling of post-flare coronal loops. This behavior suggests that the ELP is predominantly associated with plasma cooling, with relatively weak additional energy input from magnetic reconnection, which does not produce a significant enhancement in line-widths. The estimated non-thermal velocity decreases from $\sim$36 km s$^{-1}$ during the impulsive phase to $\sim$21 km s$^{-1}$ during the gradual phase, indicating a reduction in turbulent plasma motions. And doppler velocities evolve from predominantly positive values during the eruptive rise phase to negative values during the later gradual phase, implying upward and subsequent downward plasma motions. To our knowledge, this study provides the first space-based spectroscopic evidence linking coronal green-line emission with the ELP and its origin during a solar flare.
发表机构
- Indian Institute of Astrophysics（印度天体物理研究所）
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