14 pages, 7 figures, an mp4 movie has been included as an ancillary file as a supplement to figure 1, Accepted for publication in the Astrophysical Journal
Images of the solar corona by extreme-ultraviolet (EUV) telescopes reveal elegant arches of glowing plasma that trace the corona's magnetic field. Typically, these loops are preferentially illuminated segments of an arcade of vaulted field lines and such loops are often observed to sway in response to nearby solar flares. A flurry of observational and theoretical effort has been devoted to the exploitation of these oscillations with the grand hope that seismic techniques might be used as probes of the strength and structure of the corona's magnetic field. The commonly accepted viewpoint is that each visible loop oscillates as an independent entity and acts as a one-dimensional (1D) wave cavity for magnetohydrodynamic (MHD) kink waves. We argue that for many events, this generally accepted model for the wave cavity is fundamentally flawed. In particular, the 3D magnetic arcade in which the bright loop resides participates in the oscillation. Thus, the true wave cavity is larger than the individual loop and inherently multidimensional. We derive the skin depth of the near-field response for an oscillating loop and demonstrate that most loops are too close to other magnetic structures to oscillate in isolation. Further, we present a simple model of a loop embedded within an arcade and explore how the eigenmodes of the arcade and the eigenmodes of the loop become coupled. In particular, we discuss how distinguishing between these two types of modes can be difficult when the motions within the arcade are often invisible.
Secondary Waves, and/or the "Reflection" From and "Transmission" Through a Coronal Hole of an EUV Wave Associated With the 2011 February 15 X2.2 Flare Observed With SDO/AIA and STEREO/EUVI
Determining the Polarisation of a Coronal Standing Kink Oscillation Using Spectral Imaging Techniques with the Coronal Multi-channel Polarimeter (CoMP)
University of St Andrews（圣安德鲁斯大学）；School of Mathematics and Statistics, University of St Andrews（圣安德鲁斯大学数学与统计学院）；University of Newcastle（纽卡斯尔大学）；School of Information and Physical Sciences, University of Newcastle（纽卡斯尔大学信息与物理科学学院）；Rosseland Centre for Solar Physics, University of Oslo（奥斯陆大学罗斯兰太阳物理中心）
Observational Signatures of Waves and Flows in the Solar Corona
在扩展的日冕环结构中已经观察到了许多年的扰动，但在慢（传播）磁声波和/或准周期性上升流方面的解释仍然没有得到解决。我们使用前向建模来构建与简单的慢磁声波或周期性流动模型相关的观测签名。观测签名计算的171 Fe ix和193 Fe xii谱线。虽然流动和波浪模型之间存在许多差异，但我们没有发现任何可以孤立使用的明确，可靠的观测特征（即不依赖于模型之间的比较）。对于波模型，发现作为（浅）视线角度的函数的平均线宽的相对快速的变化，而线宽振幅与多普勒速度振幅的比率对于流动模型是相对高的。发现的最稳健的观测特征是，对于流动模型，多普勒速度的平均值与振幅的比率总是高于1。这个比率对于流动来说比对于波来说要高得多，并且对于研究中使用的流动模型来说，在171 Fe ix和193 Fe xii谱线中完全相同。然而，这些潜在的观测特征需要谨慎对待，因为它们可能依赖于模型。
