优先级 80 · 太阳耀斑
Origin of small-scale evaporation flows deep in the chromosphere during a solar flare
太阳耀斑期间色球深处小尺度蒸发流的起源
✉ L. P. Chitta (Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany), H. N. Smitha (Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany), F. A. Iglesias (Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany; Grupo de Estudios en Heliofísica de Mendoza, CONICET, Universidad de Mendoza, Mendoza, Argentina) et al.
原文摘要Abstract
Flares are caused by an abrupt release of magnetic energy in the solar atmosphere. Plasma heated to well over 10 MK filling the post-flare corona originates from a rapid heating and ablation of the cooler chromospheric material. This chromospheric evaporation is thought to be facilitated primarily by nonthermal electrons impinging on to the lower atmosphere. Questions on when and where in the chromosphere these upflows originate, however, are not fully resolved. Here we report on unprecedented high-resolution observations of an M-class flare recorded by the Sunrise Ultraviolet Spectropolarimeter and Imager on board the balloon-borne SUNRISE observatory, that reveal highly structured upflows on spatial scales of ~100 km originating deep in the chromosphere. The flows even precede the onset of nonthermal electrons by about 10 minutes and last through the impulsive phase of the flare. Our observations shed new light on the lower atmospheric heating and mass circulation in flares that are challenging to reconcile with the standard solar flare model.
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AI-generated · 以原文为准
亮点在近衍射极限(约 59 km)尺度上首次把耀斑蒸发流追至色球底部 0.5-1 Mm,并发现前兆蓝移早于非热电子,直接挑战标准耀斑模型的能量输运时序。
脉络与展望太阳耀斑的色球蒸发通常放在标准模型下理解,即日冕磁重联释放能量后由非热电子或热传导向低层大气输运 Carmichael 1964、Sturrock 1966。过去 Fe II 线的耀斑光谱研究多报道红移不对称,并用 RADYN 一维辐射动力学模型解释为凝聚下沉 Kowalski+ 2017、Graham+ 2020;而前兆期过渡区和日冕谱线的蓝移蒸发也有零散报道 Brosius+ 2004、Dudík+ 2016。本文把这一前兆蓝移证据第一次延伸到约 0.5-1 Mm 的色球底部,并显示蓝移与红移在 60-100 km 尺度上高度结构化、早于脉冲相硬 X 射线约 10 分钟,这对标准模型的下层能量注入时序构成挑战。未来结合更高灵敏度的前兆 HXR 观测、黑子/半影型大气辐射动力学模拟以及多层温度覆盖的 UV 光谱诊断,有望区分低层大气局地重联、热传导和阿尔芬波输运等竞争通道。
预印本 2026-08-30 · 接收 2026-08-29 · 刊出 2026-09-10 · 收录 2026-09-01