Analysis of Slow Partial Halo CME Events with Velocity of 100-200 km/s: An Observation through CALLISTO System

Abstract

Halo event of coronal mass ejections (CMEs) had been once in a while reported in coronagraph observations of the Sun before the Solar and Heliospheric Observatory (SOHO) mission has been carried out. However, since mid-1996 the SOHO Large Angle Spectrometric Coronagraph (LASCO) instruments have observed numerous or partial-halo CMEs. Partial is when CMEs aimed at Earth which is called as halo because of the way they look in coronagraph images. As the expanding cloud of an Earth-directed CME becomes larger and it appears to envelop the Sun, forming a around our star. Statistical interpretation states that most of the halos CMEs occur at average speed of ~957 km/s. In 2015, eight (8) CMEs events were detected accompanied by slow partial CMEs. Sunspot number, solar radio flux and solar wind involves in interpreting the slow movements of CMEs. In this paper, we study partial CME events with slow velocity and we discussed the slow partial CMEs which is due to the weak magnetic fields affect from low solar radio flux and solar wind fluctuation. The slow CME events were observed through CALLISTO System and compare it with database from CACTUS. As a result, we found that there are slow CMEs occur with velocity as low as 100- 200km/s.