THE PERIOD RATIO FOR STANDING KINK AND SAUSAGE MODES IN SOLAR STRUCTURES WITH SIPHON FLOW. I. MAGNETIZED SLABS
THE PERIOD RATIO FOR STANDING KINK AND SAUSAGE MODES IN SOLAR STRUCTURES WITH SIPHON FLOW. I. MAGNETIZED SLABS
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DOI：
10.1088/0004-637x/767/2/169
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发表时间：
2013-03
期刊：
影响因子：
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通讯作者：
Bo Li;S. Habbal;Yan-Jun Chen
中科院分区：
文献类型：
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作者：
Bo Li;S. Habbal;Yan-Jun Chen
在太阳磁震学的应用中，基模周期与其第一泛音周期的两倍之比P1/2P2起着重要的作用。我们研究如何场对准流影响的色散特性，因此，在太阳大气中的磁板支持的常设模式的周期比。我们数值求解色散关系，并设计了一个图形的方法来构建驻波模。对于日冕板块，我们发现，流动的影响是显着的快速扭结和香肠模式一样。对于扭折的，他们可能会减少P1/2P2高达23%相比，静态的情况下，和最小允许P1/2P2可以下降到静态板解析推导的下限以下。对于香肠模式，虽然引入流相对于静态情况通常将P1/2P2减小了约5%，但它显著增加了阈值纵横比，仅在该阈值纵横比以上可以支持站立的香肠模式，这意味着它们的可检测性被限制到甚至更宽的板。在光球板块的情况下，流动效应没有那么强。然而，站立模式是不同的冠状面的情况下，站立扭结模式显示P1/2P2，偏离统一，即使是零宽度板，而站立香肠模式不再遭受阈值纵横比。我们的结论是横向结构等离子体密度和流速应考虑在地震学应用的多周期性太阳大气结构。
In the applications of solar magneto-seismology, the ratio of the period of the fundamental mode to twice the period of its first overtone, P1/2P2, plays an important role. We examine how field-aligned flows affect the dispersion properties, and hence the period ratios, of standing modes supported by magnetic slabs in the solar atmosphere. We numerically solve the dispersion relations and devise a graphic means to construct standing modes. For coronal slabs, we find that the flow effects are significant for the fast kink and sausage modes alike. For the kink ones, they may reduce P1/2P2 by up to 23% compared with the static case, and the minimum allowed P1/2P2 can fall below the lower limit analytically derived for static slabs. For the sausage modes, while introducing the flow reduces P1/2P2 by typically ≲ 5% relative to the static case, it significantly increases the threshold aspect ratio only above which standing sausage modes can be supported, meaning that their detectability is restricted to even wider slabs. In the case of photospheric slabs, the flow effect is not as strong. However, standing modes are distinct from the coronal case in that standing kink modes show a P1/2P2 that deviates from unity even for a zero-width slab, while standing sausage modes no longer suffer from a threshold aspect ratio. We conclude that transverse structuring in plasma density and flow speed should be considered in seismological applications of multiple periodicities to solar atmospheric structures.