Evolution of the photospheric magnetic field in the source regions of coronal mass ejections

Durgesh Tripathi

EIT (Extreme-ultraviolet Imaging Telescope), LASCO (Large Angle Spectrometric Coronagraph) and MDI (Michelson Doppler Imager) on board SoHO (Solar and Heliospheric Observatory) provide and unprecedented opportunity to study the source regions of coronal mass ejections (CMEs) in the low corona as well as in the Photosphere. Here we present a study of association of post-eruptive arcades (PEAs) observed on the solar disk by EIT at 195 with CMEs. We found that each and every PEAs observed by EIT have an associated CME. Therefore EUV PEAs can be considered as the reliable tracers of CME source regions on the solar disk. Further, we selected 7 PEA events associated with filaments in order to study the magnetic field in the source region based on the MDI magnetograms. Based on these observations, for two events evidence for magnetic flux cancellation was detected. For other two events one of the foot-points of the filament was rooted close to a near by evolving active region. However in three cases emergence of new flux was seen. Therefore, we conclude that different varieties of evolutions in the Photospheric magnetic field can lead to CME eruptions. The upcoming missions like SOLAR-B will help us understand the evolution of Photospheric magnetic field in terms of CME eruptions.

Correspondence

Durgesh Tripathi, Department of Applied Mathematics and Theoretical Physics

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