Long-period oscillations in solar coronal bright points

被引：0

作者：

Tian, H. ^{[1
,2
]}

Xia, L.-D. ^{[3
]}

Li, S. ^{[2
,4
]}

机构：

[1] Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany

[2] Department of Geophysics, Peking University, Beijing, China

[3] School of Space Science and Physics, Shandong Univ. at Weihai, Weihai, Shandong, China

[4] Department of Physics, Stanford University, Stanford, CA 94305, United States

来源：

Astronomy and Astrophysics | 2008年 / 489卷 / 02期

关键词：

Aims. By analyzing TRACE (Transition Region and Coronal Explorer) data; we investigate intensity oscillations in coronal bright points (BPs) as well as the underlying chromosphere.Methods. A Fourier analysis is applied to a sequence of images observed in the 195 Aand 1216 A passbands of TRACE. We produce images of Fourier power in three different period ranges (4-16 min; 20-40; min; 42-75 min). The presence of periodic oscillations are further checked by applying a wavelet analysis to a selected rectangular region in each of the three BPs. Results. We find a clear signature of oscillations with different periods dominating in different strands of BP loops in the 195 A passband. The oscillatory power is stronger in BPs than in the surrounding quiet Sun. In the chromospheric 1216 A passband; oscillations in these period ranges are found mainly above the magnetic network elements; which are not necessarily associated with the coronal BPs. The wavelet analyses reveal that oscillations with periods ranging from 8 to 64 min can last for several cycles in both the BPs and the underlying chromosphere.Conclusions. It is still unclear whether these oscillations are caused by propagating magneto-acoustic waves in loop systems associated with the BPs; or result from recurrent magnetic reconnection powering the BPs. © 2008 ESO;

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摘要：

Journal article (JA)

引用

页码：741 / 745