On propagation of gradual and impulsive Coronal Mass Ejections (CMEs)

Abstract

Coronal Mass Ejection (CME) is a significant solar activity that releases magnetic field and plasma out of the corona and they are known as the main driver of space weather. In general, CMEs are characterized as gradual and impulsive based on their kinematic properties that include velocity and acceleration. This paper is aimed to analyze the differences in behaviour of gradual and impulsive CME based on recent events (dates) in solar cycle 25 and to justify their characterizations that have been demonstrated a while ago. Data analysis is conducted by studying the height-time, height-velocity and height-acceleration profiles for each event, based on SOHO LASCO Catalogue. Results show that impulsive CME travels a lot faster than gradual CME, with average velocity of 1239 km/s and 503.6 km/s respectively. It is believed that M6.7 flare accompanying the impulsive CME has been the main reason to high velocity due to its ability to contribute more heat energy and enhances the energy conversion during magnetic reconnection. Deceleration is observed in impulsive CME that is caused by the loss of momentum as interacting with the background solar wind and small-scale acceleration is manifested by gradual CME all through the propagation.