Kink Oscillation of a Flux Rope During a Failed Solar Eruption
Kink Oscillation of a Flux Rope During a Failed Solar Eruption
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DOI：
10.3847/2041-8213/ac6e3e
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发表时间：
2022-06-01
影响因子：
7.9
通讯作者：
Cho, Kyung-Suk
中科院分区：
文献类型：
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作者：
Kumar, Pankaj;Nakariakov, Valery M.;Cho, Kyung-Suk
我们报告了在一次有限的爆发耀斑期间，由太阳动力学天文台的大气成像组件（AIA）在太阳边缘观测到的通量绳的衰减扭结振荡，该装置缺乏可探测的白光日冕物质抛射。喷发的通量绳在事件中经历了扭结、旋转和明显的腿-腿相互作用。在304埃、171埃和193埃的多个AIA通道中同时观察到振荡，表明多热等离子体被夹带在绳索中。磁通绳到达活跃区的上环后，呈现出大振幅、衰减的扭结振荡，初振幅为30 Mm，衰减周期约为16分钟，衰减时间约为17分钟。我们将这些振荡解释为通量绳的一种基本的常扭结模式。振荡极化具有明显的垂直分量，而检测到的波形偏离正弦信号表明振荡可能是圆极化或椭圆极化。估计扭结速度为1080公里每秒（-1），对应于阿尔芬速度约760公里每秒（-1）。这个速度，加上我们从差分发射测量分析中估计的绳子中的电子密度，n (e)近似于（1.5-2.0）x 10(9) cm(-3)，产生的磁场强度约为15g。据我们所知，在受限的爆发耀斑期间，具有非水平极化的通量绳子的衰减扭结振荡尚未有过报道。这些振荡为间接测量失败喷发期间低日冕通量绳中的磁场强度提供了独特的机会。
We report a decaying kink oscillation of a flux rope during a confined eruptive flare, observed off the solar limb by the Solar Dynamics Observatory's Atmospheric Imaging Assembly (AIA), which lacked a detectable white-light coronal mass ejection. The erupting flux rope underwent kinking, rotation, and apparent leg-leg interaction during the event. The oscillations were observed simultaneously in multiple AIA channels at 304, 171, and 193 angstrom, indicating that multithermal plasma was entrained in the rope. After reaching the overlying loops in the active region, the flux rope exhibited large-amplitude, decaying kink oscillations with an apparent initial amplitude of 30 Mm, a period of about 16 minutes, and a decay time of about 17 minutes. We interpret these oscillations as a fundamental standing kink mode of the flux rope. The oscillation polarization has a clear vertical component, while the departure of the detected waveform from a sinusoidal signal suggests that the oscillation could be circularly or elliptically polarized. The estimated kink speed is 1080 km s(-1), corresponding to an Alfven speed of about 760 km s(-1). This speed, together with the estimated electron density in the rope from our differential emission measure analysis, n ( e ) approximate to (1.5-2.0) x 10(9) cm(-3), yields a magnetic-field strength of about 15 G. To the best of our knowledge, decaying kink oscillations of a flux rope with nonhorizontal polarization during a confined eruptive flare have not been reported before. These oscillations provide unique opportunities for indirect measurements of the magnetic-field strength in low-coronal flux ropes during failed eruptions.