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arXiv 2109.14736astro-ph.SR
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IRIS观测到的小尺度增亮的多波长分析

A multi-wavelength analysis of small-scale brightenings observed by IRIS

Llŷr Dafydd Humphries, Huw Morgan

摘要:

太阳大气观测中的小尺度增亮是加热和/或能量传输事件的表现。我们通过应用于1330、1400和2796 Å IRIS斜颌图像时间序列的新检测方法呈现了亮度的统计特征。共记录了2377个事件,这些事件在所有三个通道中共存,使人们高度相信它们是真实的。这些中的$\approx$ 1800是空间相干的,等于在34.5分钟内$90\arcsec\times100\arcsec$ FOV内的$\sim9.7\times10^{-5}$ arcsec $^{-2}$ s $^{-1}$的事件密度。确定总亮度($2.78<α<3.71$)、最大亮度($3.84<α<4.70$)和平均面积($4.31<α<5.70$)分布的幂律指数估计。持续时间和速度分布不服从幂律。事件的空间碎片化,面积和持续时间之间的相关性,以及与总亮度的弱关系,表明更大/更长的持续时间的事件更有可能在其生命周期中的碎片。速度分布显示所有事件都处于运动中,平均速度为$\sim7$ \kms。这些事件的空间轨迹表明,较冷的2796次事件倾向于稍晚出现,并占据与较热通道结果不同的位置/轨迹。这表明,其中许多是由重连引起的脉冲事件,随后迅速冷却,或者触发事件发生在TR附近,随后传播到较冷的大气层的扰动。事件的空间分布并不均匀,广泛的区域没有事件。空间分布与其他大气层的属性的比较表明,高磁场强度,日冕的多热性,高IRIS增亮活动之间的初步联系。

英文摘要:

Small-scale brightenings in solar atmospheric observations are a manifestation of heating and/or energy transport events. We present statistical characteristics of brightenings from a new detection method applied to 1330, 1400, and 2796 Å IRIS slitjaw image time series. 2377 events are recorded which coexist in all three channels, giving high confidence that they are real. $\approx$1800 of these are spatially coherent, equating to event densities of $\sim9.7\times10^{-5}$arcsec$^{-2}$s$^{-1}$ within a $90\arcsec\times100\arcsec$ FOV over 34.5 minutes. Power Law indices estimates are determined for total brightness ($2.78<α<3.71$), maximum brightness ($3.84<α<4.70$), and average area ($4.31<α<5.70$) distributions. Duration and speed distributions do not obey a power law. A correlation is found between the events' spatial fragmentation, area, and duration, and a weak relationship with total brightness, showing that larger/longer-lasting events are more likely to fragment during their lifetime. Speed distributions show that all events are in motion, with an average speed of $\sim7$\kms. The events' spatial trajectories suggest that cooler 2796 Å events tend to appear slightly later, and occupy a different position/trajectory to the hotter channel results. This suggests that either many of these are impulsive events caused by reconnection, with subsequent rapid cooling, or that the triggering event occurs near the TR, with a subsequent propagating disturbance to cooler atmospheric layers. The spatial distribution of events is not uniform, with broad regions devoid of events. A comparison of spatial distribution with properties of other atmospheric layers shows a tentative connection between high magnetic field strength, the corona's multithermality, and high IRIS brightening activity.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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