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.