SDO/HMI survey of emerging active regions for helioseismology
SDO/HMI survey of emerging active regions for helioseismology
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SDO/HMI 日震学新兴活跃区域调查
DOI：
10.1051/0004-6361/201628388
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
L. Gizon
中科院分区：
文献类型：
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作者：
H. Schunker;D. Braun;A. Birch;R. Burston;L. Gizon
太阳动力学观测站（SDO）的观测有可能对数百个活动区域的形成进行日震研究，这将使我们能够进行统计分析。我们的目标是整理出一套统一的数据集，这些数据集是由SDO/HMI仪器观测到的，适用于日震分析，最长可达7天。我们将样本限制在连续体中可见的活跃区域，并出现在安静的太阳中，很大程度上避免了先前存在的磁性区域。作为参考数据集，我们将一个具有相同纬度和距离中心子午线距离的控制区（CR）与每个新出现的活跃区（EAR）配对。我们称这些数据集为SDO日震新活跃区（SDO/HEAR）调查，这些数据集目前由2010年5月至2012年11月观测到的105个新活跃区组成。为了证明大量新出现的活跃区域数据集的实用性，我们在出现后的第一天从视线磁图中测量了前后极性的相对东西速度。所有ear的纬向平均视距磁场显示，相对于卡灵顿旋转速率，平均而言，第一天的前（后）极性以121 +/- 22 m/s （-70 +/- 13 m/s）的速度向正（逆行）方向移动。然而，相对于表面等离子体的微分旋转，东西速度是对称的，平均为95 +/- 13 m/s。SDO/HEAR数据集不仅可用于日震研究，还可用于研究其他特征，如大型ear样本的表面磁场演化。
Observations from the Solar Dynamics Observatory (SDO) have the potential for allowing the helioseismic study of the formation of hundreds of active regions, which would enable us to perform statistical analyses. Our goal is to collate a uniform data set of emerging active regions observed by the SDO/HMI instrument suitable for helioseismic analysis up to seven days before emergence. We restricted the sample to active regions that were visible in the continuum and emerged into quiet Sun largely avoiding pre-existing magnetic regions. As a reference data set we paired a control region (CR), with the same latitude and distance from central meridian, with each emerging active region (EAR). We call this data set, which is currently comprised of 105 emerging active regions observed between May 2010 and November 2012, the SDO Helioseismic Emerging Active Region (SDO/HEAR) survey. To demonstrate the utility of a data set of a large number of emerging active regions, we measure the relative east-west velocity of the leading and trailing polarities from the line-of-sight magnetogram maps during the first day after emergence. The latitudinally averaged line-of-sight magnetic field of all the EARs shows that, on average, the leading (trailing) polarity moves in a prograde (retrograde) direction with a speed of 121 +/- 22 m/s (-70 +/- 13 m/s) relative to the Carrington rotation rate in the first day. However, relative to the differential rotation of the surface plasma, the east-west velocity is symmetric, with a mean of 95 +/- 13 m/s. The SDO/HEAR data set will not only be useful for helioseismic studies, but will also be useful to study other features such as the surface magnetic field evolution of a large sample of EARs.