Analysis of Forbush decreases observed using a muon telescope in Antarctica starting on 21 June 2015
Analysis of Forbush decreases observed using a muon telescope in Antarctica starting on 21 June 2015
复制标题
对 2015 年 6 月 21 日开始使用南极洲 μ 子望远镜观测到的福布什减少的分析
DOI：
10.1088/1674-1137/42/12/125001
复制
发表时间：
2018
影响因子：
3.6
通讯作者：
吕景天
中科院分区：
文献类型：
--
作者：
黄德宏;胡红桥;张吉龙;卢红;张大力;薛炳森;吕景天
宇宙射线μ子望远镜自2014年底以来一直在收集数据，这是在南极中山站建造望远镜后不久。该望远镜是中国科学家在南极建造的第一个观测装置。中山站气压变化很大。压力校正结果的计数率表明，计数率的大变化可能是由压力波动引起的。在2015年6月18日至22日期间，有四次日冕物质抛射（CME）从太阳中喷射出来。这些CME在到达地球时引发了一系列的福布什减少（FD）。我们对FD期间记录的银河宇宙线强度波动进行了全面研究。本研究中使用的强度起伏是由多个站（中山站、麦克默多站、南极站和名古屋站）的宇宙线探测器收集的，太阳风测量是由ACE和WIND收集的。6月22日的FD曲线显示了四步下降。传统的一步或两步FD分类方法不能充分解释FD轮廓结果。应该考虑2015年6月21日发生的更快的CME和前几天的两次缓慢CME之间的相互作用。南极站、麦克默多站和中山站的宇宙线强度具有相似的小时变化，而在极地和非极地位置之间记录的银河宇宙线是不同的。名古屋μ子望远镜（非极地位置）2015年6月22日的FD预增比麦克默多和中山站（极地位置）晚1 h。名古屋μ子望远镜2015年6月22日的FD开始滞后于极地位置的FD开始1小时。
A cosmic-ray muon telescope has been collecting data since the end of 2014, which was shortly after the telescope was built in the Zhongshan Station of Antarctica. The telescope is the first observation device to be built by Chinese scientists in Antarctica. The pressure change is very strong in Zhongshan station. The count rate of the pressure correction results shows that the large variations in the count rate are likely caused by pressure fluctuations. During the period from 18 June to 22 June 2015, four halo coronal mass ejections (CMEs) were ejected from the Sun. These CMEs initiated a series of Forbush decreases (FD) when they reached the Earth. We conducted a comprehensive study of the intensity fluctuations of galactic cosmic rays recorded during FDs. The intensity fluctuations used in this study were collected by cosmic ray detectors of multiple stations (Zhongshan, McMurdo, South Polar, and Nagoya), and the solar wind measurements were collected by ACE and WIND. The profile of the FD of 22 June demonstrated a four-step decrease. The traditional one- or two-step FD classification method does not adequately explain the FD profile results. The interaction between the faster CME that occurred on 21 June 2015 and the two slow CMEs of the earlier few days should be considered. The cosmic ray intensities of the South Pole, McMurdo, and Zhongshan stations have similar hourly variations, whereas the galactic cosmic rays recorded between polar and non-polar locations are distinct. The FD pre-increase of 22 June 2015 for the Nagoya muon telescope (non-polar location) lags those of the McMurdo and Zhongshan stations (polar locations) by 1 h. The FD onset of 22 June 2015 for the Nagoya muon telescope lags those of the polar locations by 1 h.