UBIQUITOUS TORSIONAL MOTIONS IN TYPE II SPICULES
UBIQUITOUS TORSIONAL MOTIONS IN TYPE II SPICULES
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DOI：
10.1088/2041-8205/752/1/l12
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发表时间：
2012-05
期刊：
影响因子：
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通讯作者：
B. Pontieu;M. Carlsson;L. R. Voort;R. Rutten;V. Hansteen;H. Watanabe
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文献类型：
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作者：
B. Pontieu;M. Carlsson;L. R. Voort;R. Rutten;V. Hansteen;H. Watanabe
针状体是细长的、高度动态的特征，从太阳边缘无处不在地突出出来。它们控制着色球和日冕之间的界面，并可能为日冕提供大量的质量和能量。我们利用瑞典1m太阳望远镜的高质量观测资料，建立了所谓的II型针状体的特征：(1)50-100公里S−1阶场向流动；(2)15-20公里S−1阶摆动运动；(3)25-30公里S−1阶扭转运动。前两种模式已被详细研究过，但没有扭转运动。我们对许多近肢和离肢光谱以及使用多条谱线的窄带图像的分析得出了强有力的证据，即大多数(如果不是全部)II型针状体经历了大的扭转调制，这些运动，就像针状体的摆动一样，代表着在数百公里处向外传播的阿尔夫尼波S−1。不同运动的综合作用解释了色球线外部红色和蓝色翼中针状丛的相似形态，在解释多普勒运动时需要考虑到，以推导针状物中场向流动的估计，并确定太阳大气中的阿尔夫尼克波能量。我们的结果还表明，大扭转运动是产生II型针状物的一个因素，并且针状物在螺旋度通过太阳大气的传输中起着重要作用。
Spicules are long, thin, highly dynamic features that jut out ubiquitously from the solar limb. They dominate the interface between the chromosphere and corona and may provide significant mass and energy to the corona. We use high-quality observations with the Swedish 1 m Solar Telescope to establish that so-called type II spicules are characterized by the simultaneous action of three different types of motion: (1) field-aligned flows of order 50–100 km s−1, (2) swaying motions of order 15–20 km s−1, and (3) torsional motions of order 25–30 km s−1. The first two modes have been studied in detail before, but not the torsional motions. Our analysis of many near-limb and off-limb spectra and narrowband images using multiple spectral lines yields strong evidence that most, if not all, type II spicules undergo large torsional modulation and that these motions, like spicule swaying, represent Alfvénic waves propagating outward at several hundred km s−1. The combined action of the different motions explains the similar morphology of spicule bushes in the outer red and blue wings of chromospheric lines, and needs to be taken into account when interpreting Doppler motions to derive estimates for field-aligned flows in spicules and determining the Alfvénic wave energy in the solar atmosphere. Our results also suggest that large torsional motion is an ingredient in the production of type II spicules and that spicules play an important role in the transport of helicity through the solar atmosphere.