Search for Rapid Changes in the Visible-Light Corona during the 21 June 2001 Total Solar Eclipse
Search for Rapid Changes in the Visible-Light Corona during the 21 June 2001 Total Solar Eclipse
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寻找 2001 年 6 月 21 日日全食期间可见光日冕的快速变化
DOI：
10.1007/s11207-010-9647-8
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发表时间：
2010
期刊：
影响因子：
2.8
通讯作者：
Rudawy P
中科院分区：
文献类型：
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作者：
Rudawy P
对 2001 年 6 月 21 日全食期间使用位于赞比亚卢萨卡的日食日冕成像系统 (SECIS) 快帧 CCD 相机仪器获得的约 8000 张图像进行了分析，以寻找强度的短周期振荡，这可能是 MHD 波耗散的日冕加热机制的特征。图像是在白光和 Fexivgreen 线 (5303 Å) 通道中拍摄的，历时 205 秒（帧速率 39 s−1），大约是该位置日全食的长度，像素大小为四角秒平方。这些数据的质量比我们在 1999 年 8 月 11 日全食期间获得的数据要好得多（Rudawyet al.:Astron. Astrophys.416, 1179, 2004），因为图像的曝光效果更好，并且所使用的定日镜驱动系统的增强大大提高了图像稳定性。经典傅里叶和小波技术已用于分析 29 518 个位置的发射，其中 10 714 个位置的发射水平相当高，搜索周期在 0.1 – 17 秒范围内的周期性波动（频率 0.06 – 10 Hz）。虽然小波分析中存在许多可能的周期性，但局部亮度曲线中的空间和时间限制的周期性在物理上并不重要。这意味着使用冠状多通道旋光计 (CoMP) 仪器进行旋光观测时普遍存在的阿尔芬波状现象 (Tomczyket al.:Science317, 1192, 2007) 不会引起显着的振荡强度波动。
Some 8000 images obtained with theSolar Eclipse Coronal Imaging System(SECIS) fast-frame CCD camera instrument located at Lusaka, Zambia, during the total eclipse of 21 June 2001 have been analysed to search for short-period oscillations in intensity that could be a signature of solar coronal heating mechanisms by MHD wave dissipation. Images were taken in white-light and Fexivgreen-line (5303 Å) channels over 205 seconds (frame rate 39 s−1), approximately the length of eclipse totality at this location, with a pixel size of four arcseconds square. The data are of considerably better quality than those that we obtained during the 11 August 1999 total eclipse (Rudawyet al.:Astron. Astrophys.416, 1179, 2004), in that the images are much better exposed and enhancements in the drive system of the heliostat used gave a much improved image stability. Classical Fourier and wavelet techniques have been used to analyse the emission at 29 518 locations, of which 10 714 had emission at reasonably high levels, searching for periodic fluctuations with periods in the range 0.1 – 17 seconds (frequencies 0.06 – 10 Hz). While a number of possible periodicities were apparent in the wavelet analysis, none of the spatially and time-limited periodicities in the local brightness curves was found to be physically important. This implies that the pervasive Alfvén wave-like phenomena (Tomczyket al.:Science317, 1192, 2007) using polarimetric observations with theCoronal Multi-Channel Polarimeter(CoMP) instrument do not give rise to significant oscillatory intensity fluctuations.