基于多视角观测的SEP事件与twin-CME关系研究

本文联合SOHO和STEREO-A/B（三视角）日冕观测和太阳高能粒子（SEP）观测，分析了2007—2014年间169个快速（速度>900 km·s^-1）、宽角度（>60°）日冕物质抛射（CME）及其先行CME和关联SEP事件.通过相关分析，给出了SOHO/EPHIN 25~53MeV及STEREO/HET 23.8~60 MeV能量范围的大SEP事件通量判断阈值，分别为0.01和0.014（cm²·s·sr·MeV）^-1.三视角CME观测能有效地避免投影效应产生的twin-CME事件误判，统计得到单一视角确定twin-CME事件的误判率一般低于10%，最高不超过15%.基于三视角判断的twin-CME事件及SEP事件峰值强度，得到判断twin-CME事件的时间阈值最短约为9 h（9~13 h）.single-CME产生的SEP事件强度与CME速度、动能的相关性明显高于twin-CME，并且三视角下的相关性结果与单视角类似.结果表明，一个主CME可能存在多个先行CME，依据单卫星观测判断先行CME时有一定的误判几率，但少数单个先行CME的误判并不影响基于单卫星的统计规律或统计结果.

On the relationship between large SEP event and twin-CME with the observations from multiple-vantage spacecraft

In this paper, we investigated 169 fast and wide coronal mass ejection (CME) and their associated solar energetic particle (SEP) events detected by SOHO and STEREO-A/B spacecraft from three-vantage viewpoints from 2007 to 2014. The flux threshold of defining a large SEP event was suggested to be 0.01 and 0.014 (cm²s·sr·MeV)^-1 respectively for SOHO/EPHIN at 25~53 MeV and STEREO/HET at 23.8~60 MeV. The multiple-vantage observations can well rule out some misidentifications of twin-CME events due to the projection effect of CME detection. The results show that the percentage of misidentified twin-CMEs by only one spacecraft SOHO is generally lower than 10%, and not more than 15% ultimately. The time interval threshold of identifying a preceding CME ahead a main CME should be larger than about 9 hours and less than 13 hours from the analysis by three-vantage spacecraft. The correlation between SEP intensity and the speed, kinetic energy of CME is significantly higher for single-CME events than that for twin-CME events. From three-vantage observations, the statistical results is generally consistent with those results only from single-one view. Because one CME usually has more than one preceding CMEs, it seems to be shown that there is no obvious effects on the results from single-view observations in statistical analysis despite of the misidentification of few preceding CMEs.