Hemispheric Distribution of Halo Coronal Mass Ejection Source Locations

Abstract

The hemispheric asymmetry of solar activity is one of the essential physical consequences of the interior dynamo process. However, the hemispheric distribution of halo coronal mass ejection (HCME) source locations has not been investigated in detail. Based on the HCME catalog identified from the Large Angle and Spectrometric Coronagraph Experiment on board the Solar and Heliospheric Observatory, we perform a hemispheric distribution analysis of the HCME source locations from 1996 April to 2022 June. The main results are as follows. (1) The HCME source locations are confined to the active region belt, and there is no “rush to the poles” phenomenon that is unique to large-scale magnetic activity. (2) The HCME source locations exhibit a general hemispheric asymmetry, and autoregressive moving-average model results show that the asymmetry of HCME source locations is significantly different from that of sunspot activity. (3) The hemispheric distribution of cycle 24 is different from that of cycle 23, potentially as a result of the heliospheric dynamic pressure having noticeably decreased after the polarity reversal of cycle 23. Our results contribute to a more comprehensive understanding of the hemispheric asymmetry of energetic magnetic structures and give a new perspective on understanding the geoeffectiveness of HCMEs.