Relationship between speed of Full Halo Coronal Mass Ejections and Cosmic ray intensity

Abstract

Halo and Full Halo CMEs (Coronal Mass Ejections) events observed by Solar and Heliospheric observatory (SOHO) mission are used to study their effects on cosmic ray intensity variations during 2009 to 2012, which correspond to ascending phase of recent solar cycle 24. It is found that the speed of HCMEs (Halo Coronal Mass Ejections) are significantly negative correlated with cosmic ray intensity. All the FHCMEs (Full Halo Coronal Mass Ejections) having the linear speed  1000 km/s produce transient decrease in cosmic ray intensity on short-term basis. The results of analysis indicated that the magnitude of decrease in cosmic ray intensity is large for high speed FHCMEs (Full Halo Coronal Mass Ejections) in comparison with low speed FHCMEs (Full Halo Coronal Mass Ejections).