冕洞发展及其相关地球空间效应的个例分析

利用出现在2003-2004年的一个大冕洞及其相关太阳风、行星际磁场和地磁资料,分析了冕洞自身演化规律以及对太阳风和重现性地磁暴的影响.研究发现,冕洞发展经历了生长期、成熟期和衰减期三个阶段;成熟期,冕洞高速流中的最大太阳风速度和地磁暴平均强度基本维持在同一个水平上;但地磁暴的持续时间和冕洞高速流的持续时间仍有较大变化,该时间长短主要与冕洞穿越太阳赤道部分所横跨的经度相关.

One Case Study About the Development of Coronal Hole and the Correlative Earth Effects

The evolutionary features of the coronal hole, the interplanetary and geomagnetic field effects were studied in this paper using the data of a significant coronal hole which recurred between 2003 and 2004, and the data of its correlative solar wind, interplanetary magnetic field (IMF) and geomagnetic field. It is found that the development of the coronal hole can be separated into three phases according to the geomagnetic field effects of coronal hole. That is growth phase, maturation phase and decay phase. There are different characters among these three phases. During maturation phase, the maximum solar wind speed of the high speed stream and the average effect to magnetic field maintain a same level. That means the peak of solar wind speed and the corresponding geomagnetic index (average ∑Kp and maximum ∑Kp) are confined. On the other hand, the structure of this coronal high speed stream and the corresponding recurrent geomagnetic storm are studied. Then it is found that the high speed streams have steady structures on the maturation phase, and the durations of recurrent geomagnetic storms were varied with the high-speed streams. Meanwhile the duration of the high speed is related to the shape and development of the coronal hole, especially to the longitudinal extend of the coronal hole in equator.