摘要
Abstract
Interplanetary Coronal Massive Ejections (ICME) are major drivers of geo-magnetic storms and have great influence on the space weather environment.ICMEs can be divided into two parts:Magnetic Clouds (MC) and non-Magnetic Clouds (non-MC).MCs have large and smooth rotation in the magnetic fields' angle compared to non-MC,and they can interact with the Earth's magnetosphere more easily and cause severe space weather events.To make an insight into the ongoing Solar Cycle (Solar Cycle 24) and its MCs and non-MCs' characteristic and space weather effect,a statistical research is made on 168 ICMEs during 2008-2015 using the data from observation at 1AU.There are 68 MCs and the MC rate of ICME is 40.48％.The MCs and non-MCs' plasma parameters and their effect on the space weather,relationship with the solar activities,comparison with each other,and different appearance in Solar Cycle 23,24 were analyzed.In Solar Cycle 24,the geo-magnetic storms caused by MCs are usually stronger than those caused by non-MC.The south component of magnetic field is of great importance to cause the storms.MC occurrence has a good correlation with the Sunspot Number (SSN),while non-MC and ICME'correlation coefficient with SSN is smaller,and the number of MC shows different distributions during different solar cycle phases.MCs' magnetic field and south component of magnetic field are stronger than those of non-MC on total,but the difference between their temperature and proton density is very small.The geo-magnetic effect of MCs in Solar Cycle 24 are weaker than those in Solar Cycle 23.This is because of that the maximum south component of magnetic field,the propagation speed and the proton temperature of magnetic clouds in Solar Cycle 24 are smaller.关键词
第24太阳活动周/磁云/非磁云/行星际日冕物质抛射Key words
Solar Cycle 24/Magnetic clouds/Non-magnetic clouds/Interplanetary Coronal Mass Ejections (ICME)分类
天文与地球科学
