What Causes Faint Solar Coronal Jets from Emerging Flux Regions in Coronal Holes?
What Causes Faint Solar Coronal Jets from Emerging Flux Regions in Coronal Holes?
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DOI：
10.3847/1538-4357/abee19
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发表时间：
2021-03
期刊：
影响因子：
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通讯作者：
A. Harden;N. Panesar;R. Moore;A. Sterling;M. Adams
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作者：
A. Harden;N. Panesar;R. Moore;A. Sterling;M. Adams
利用太阳动力学天文台的EUV图像和视线磁图，我们研究了8个出现在中心盘冕洞中的双极磁区（BMR），以确定出现的磁拱是否通过与环境开放场的重联直接产生了任何明显的日冕喷流，正如Yokoyama &柴田所模拟的那样。在出现期间，每一个BMR都没有产生明显的正常亮度的极紫外日冕喷流，但每一个都产生了一个或多个微弱的极紫外日冕喷流，这些喷流在AIA 193 BMR的图像中可以分辨出来。这些喷流的尖顶比在安静区域和冕洞中观察到的微灯丝喷发产生的典型EUV喷流要暗得多，通常也要窄得多。对于来自8个新兴BMR的26个微弱射流中的每一个，我们检查微弱的塔尖是否明显是由横山和柴田制造的。我们发现：（1）这些微弱的尖顶中有16个明显起源于相反极性磁通量汇聚的地点，并显示出类似于小型喷发驱动的日冕喷流的底部增亮，（2）其他10个微弱的尖顶可能是由新兴磁拱与周围开放场的外部磁拱建筑重联的爆发造成的，重联直接由拱的出现驱动，但（3）没有一个是明确地由这种紧急驱动的重新连接。因此，对于这八个新兴的BMR，观测表明，新兴的磁拱与周围的开放领域的紧急驱动的外部重连最多产生一个喷流尖顶，比以前报道的要暗得多，更明显的日冕喷流驱动的minifilament爆发。
Using EUV images and line-of-sight magnetograms from Solar Dynamics Observatory, we examine eight emerging bipolar magnetic regions (BMRs) in central-disk coronal holes for whether the emerging magnetic arch made any noticeable coronal jets directly, via reconnection with ambient open field as modeled by Yokoyama & Shibata. During emergence, each BMR produced no obvious EUV coronal jet of normal brightness, but each produced one or more faint EUV coronal jets that are discernible in AIA 193 Å images. The spires of these jets are much fainter and usually narrower than for typical EUV jets that have been observed to be produced by minifilament eruptions in quiet regions and coronal holes. For each of 26 faint jets from the eight emerging BMRs, we examine whether the faint spire was evidently made a la Yokoyama & Shibata. We find that (1) 16 of these faint spires evidently originate from sites of converging opposite-polarity magnetic flux and show base brightenings like those in minifilament-eruption-driven coronal jets, (2) the 10 other faint spires maybe were made by a burst of the external-magnetic-arcade-building reconnection of the emerging magnetic arch with the ambient open field, with reconnection directly driven by the arch's emergence, but (3) none were unambiguously made by such emergence-driven reconnection. Thus, for these eight emerging BMRs, the observations indicate that emergence-driven external reconnection of the emerging magnetic arch with ambient open field at most produces a jet spire that is much fainter than in previously reported, much more obvious coronal jets driven by minifilament eruptions.