太阳高能粒子事件常伴随太阳耀斑和日冕物质抛射事件(Coronal Mass Ejections,CME)出现,由于太阳高能粒子事件的关键因素是双CME的相互作用,利用SOHO卫星观测的高能粒子强度、耀斑强度以及CME的相对高度与时间,通过高度与时间拟合得到...太阳高能粒子事件常伴随太阳耀斑和日冕物质抛射事件(Coronal Mass Ejections,CME)出现,由于太阳高能粒子事件的关键因素是双CME的相互作用,利用SOHO卫星观测的高能粒子强度、耀斑强度以及CME的相对高度与时间,通过高度与时间拟合得到的速度,分析了2001年4月15日和2005年1月20日的太阳高能粒子事件强度与相关双CME事件的关系,发现这两个太阳高能粒子事件中E≥10 MeV质子的强度与双CME事件无关.因此在这两次太阳高能粒子事件早期,E≥10 MeV质子的强度只与相关太阳耀斑和CME有关.展开更多
We investigated 64 pairs of interacting-CME events identified from simultaneous observations by the SOHO and STEREO spacecraft from January 2010 to August 2014, to examine the relationship between large SEP events in ...We investigated 64 pairs of interacting-CME events identified from simultaneous observations by the SOHO and STEREO spacecraft from January 2010 to August 2014, to examine the relationship between large SEP events in the energy range of ～25 to～60 MeV and properties of the interacting CMEs.We found that during CME interactions, the large SEP events in this study were all generated by CMEs with the presence of enhanced type Ⅱ radio bursts, which also have wider longitudinal distributions compared to events without a type Ⅱ radio burst or its enhancement(almost always associated with small SEP events).It seems that the signature of type Ⅱ radio burst enhancement is a good discriminator between large SEP and small or no SEP event producers during CME interactions. The type Ⅱ radio burst enhancement is more likely to be generated by CME interactions, with the main CME having a larger speed(v), angular width(WD), mass(m) and kinetic energy(Ek), and taking over the preceding CMEs. The preceding CMEs in these instances have higher v, WD, m and Ekthan those in CME pairs missing type Ⅱ radio bursts or enhancements. Generally, the values of these properties in the type-Ⅱ-enhanced events are typically higher than the corresponding non-type-Ⅱ or non-type-Ⅱ-enhanced cases for both the main and preceding CMEs. Our analysis also revealed that the intensities of associated SEP events correlate negatively with the intersection height of the two CMEs. Moreover, the overlap width of two CMEs is typically larger in type-Ⅱ-enhanced events than in non-type-Ⅱ or non-type-Ⅱ-enhanced events. Most type-Ⅱ-enhanced events and SEP events are coincident and are almost always made by the fast and wide main CMEs that sweep fully over relatively slower and narrower preceding CMEs. We suggest that a fast CME with enough energy completely overtaking a relatively narrower preceding CME, especially at low height, can drive a more energetic shock signified by the enhanced type Ⅱ radio bursts. The shock may accelerate ambient particles(likely provided by the preceding CME) and lead to large SEP events more easily.展开更多
1.引言
循环的Cache不命中率分析是编译优化中的关键技术之一.CME(Cache Miss Equation)是美国Princeton大学的S.Ghosh博士提出的循环Cache不命中率分析的计算模型[1],它以循环中数组引用的重用向量分析为基础,根据Cache数据映射的规则...1.引言
循环的Cache不命中率分析是编译优化中的关键技术之一.CME(Cache Miss Equation)是美国Princeton大学的S.Ghosh博士提出的循环Cache不命中率分析的计算模型[1],它以循环中数组引用的重用向量分析为基础,根据Cache数据映射的规则用约束条件下丢番图方程对数组引用在不同重用向量上的Cache冲突情况进行精确的描述(一般为线性约束条件),明确了方程整数解的数目与Cache不命中次数之间的关系,为较为精确地分析循环的Cache不命中率奠定了基础.展开更多
文摘太阳高能粒子事件常伴随太阳耀斑和日冕物质抛射事件(Coronal Mass Ejections,CME)出现,由于太阳高能粒子事件的关键因素是双CME的相互作用,利用SOHO卫星观测的高能粒子强度、耀斑强度以及CME的相对高度与时间,通过高度与时间拟合得到的速度,分析了2001年4月15日和2005年1月20日的太阳高能粒子事件强度与相关双CME事件的关系,发现这两个太阳高能粒子事件中E≥10 MeV质子的强度与双CME事件无关.因此在这两次太阳高能粒子事件早期,E≥10 MeV质子的强度只与相关太阳耀斑和CME有关.
基金supported at NUIST by the National Natural Science Foundation of China (NSFC) (Grant Nos. U1731105 and 41304150)the Natural Science Foundation of Jiangsu Province of China (No. BK20171456)+3 种基金sponsored also by the Qing Lan Project of Jiangsu Province for L.G. Ding (2016)supported by NSFC (Grant Nos.11522328, 11473070 and 11427803)the Youth Innovation Promotion Associationthe specialized research fund from the State Key Laboratory of Space Weather for financial support
文摘We investigated 64 pairs of interacting-CME events identified from simultaneous observations by the SOHO and STEREO spacecraft from January 2010 to August 2014, to examine the relationship between large SEP events in the energy range of ～25 to～60 MeV and properties of the interacting CMEs.We found that during CME interactions, the large SEP events in this study were all generated by CMEs with the presence of enhanced type Ⅱ radio bursts, which also have wider longitudinal distributions compared to events without a type Ⅱ radio burst or its enhancement(almost always associated with small SEP events).It seems that the signature of type Ⅱ radio burst enhancement is a good discriminator between large SEP and small or no SEP event producers during CME interactions. The type Ⅱ radio burst enhancement is more likely to be generated by CME interactions, with the main CME having a larger speed(v), angular width(WD), mass(m) and kinetic energy(Ek), and taking over the preceding CMEs. The preceding CMEs in these instances have higher v, WD, m and Ekthan those in CME pairs missing type Ⅱ radio bursts or enhancements. Generally, the values of these properties in the type-Ⅱ-enhanced events are typically higher than the corresponding non-type-Ⅱ or non-type-Ⅱ-enhanced cases for both the main and preceding CMEs. Our analysis also revealed that the intensities of associated SEP events correlate negatively with the intersection height of the two CMEs. Moreover, the overlap width of two CMEs is typically larger in type-Ⅱ-enhanced events than in non-type-Ⅱ or non-type-Ⅱ-enhanced events. Most type-Ⅱ-enhanced events and SEP events are coincident and are almost always made by the fast and wide main CMEs that sweep fully over relatively slower and narrower preceding CMEs. We suggest that a fast CME with enough energy completely overtaking a relatively narrower preceding CME, especially at low height, can drive a more energetic shock signified by the enhanced type Ⅱ radio bursts. The shock may accelerate ambient particles(likely provided by the preceding CME) and lead to large SEP events more easily.
文摘1.引言
循环的Cache不命中率分析是编译优化中的关键技术之一.CME(Cache Miss Equation)是美国Princeton大学的S.Ghosh博士提出的循环Cache不命中率分析的计算模型[1],它以循环中数组引用的重用向量分析为基础,根据Cache数据映射的规则用约束条件下丢番图方程对数组引用在不同重用向量上的Cache冲突情况进行精确的描述(一般为线性约束条件),明确了方程整数解的数目与Cache不命中次数之间的关系,为较为精确地分析循环的Cache不命中率奠定了基础.
