Detection of Three-minute Oscillations in Full-disk Lyα Emission during a Solar Flare
Detection of Three-minute Oscillations in Full-disk Lyα Emission during a Solar Flare
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DOI：
10.3847/2041-8213/aa8f3a
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发表时间：
2017-09
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影响因子：
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通讯作者：
R. Milligan;B. Fleck;J. Ireland;L. Fletcher;B. Dennis
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作者：
R. Milligan;B. Fleck;J. Ireland;L. Fletcher;B. Dennis
在这封信中，我们报告的检测色球3分钟振荡盘集成EUV辐照度观测期间的太阳耀斑。对2011年2月15日X级耀斑（SOL 2011 -02- 15 T01：56）的去趋势Lyα（来自GOES/EUVS）和莱曼连续谱（来自太阳动力学天文台（SDO）/EVE）辐射的小波分析显示，在耀斑的主相位期间存在103分钟的周期。这种发射的形成温度将这种辐射定位在耀斑的色球足点，并且在SDO/大气成像组件1600和1700的通道中发现了类似的行为，这些通道由色球连续体主导。这意味着色球层在其声学截止频率下动态地响应能量的脉冲注入。由于在硬X射线（HXR）能量（50-100 keV）下没有发现3分钟的周期，我们可以说这种3分钟的振荡不依赖于非热电子的振荡速率。然而，在HXR和色球光变曲线中发现的120秒的第二个周期与2分钟时间尺度上的偶发电子振荡一致。我们对3分钟振荡的发现表明，色球机械能应该包括在耀斑能量收支中，Lyα线的波动可能会影响高活动期间行星大气的组成和动力学。
In this Letter we report the detection of chromospheric 3-minute oscillations in disk-integrated EUV irradiance observations during a solar flare. A wavelet analysis of detrended Lyα (from GOES/EUVS) and Lyman continuum (from Solar Dynamics Observatory (SDO)/EVE) emission from the 2011 February 15 X-class flare (SOL2011-02-15T01:56) revealed a ∼3 minute period present during the flare’s main phase. The formation temperature of this emission locates this radiation at the flare’s chromospheric footpoints, and similar behavior is found in the SDO/Atmospheric Imaging Assembly 1600 and 1700 Å channels, which are dominated by chromospheric continuum. The implication is that the chromosphere responds dynamically at its acoustic cutoff frequency to an impulsive injection of energy. Since the 3-minute period was not found at hard X-ray (HXR) energies (50–100 keV) in Reuven Ramaty High Energy Solar Spectroscopic Imager data we can state that this 3-minute oscillation does not depend on the rate of energization of non-thermal electrons. However, a second period of 120 s found in both HXR and chromospheric lightcurves is consistent with episodic electron energization on 2-minute timescales. Our finding on the 3-minute oscillation suggests that chromospheric mechanical energy should be included in the flare energy budget, and the fluctuations in the Lyα line may influence the composition and dynamics of planetary atmospheres during periods of high activity.