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Upcoming Seminar/Colloqium

Topic:

Solar eruptive flares and associated coronal mass ejections: initiation and propagation characteristics

Speaker : Syed Ibrahim
Affiliation : ARIES
Date & Time :
Venue : Auditorium
Abstract :

 

In the presentation, I am going to compare the properties of two coronal mass ejections (CMEs) that show similar source region characteristics but different evolutionary behavior in the later phases. We discuss the two events in terms of their near-Sun evolution, interplanetary evolution, and geo-effectiveness. Many CMEs are erupted before and after these CMEs, but we carefully analyzed the initiation and propagation details of these events to establish the connection of corresponding CMEs-ICMEs and their near Earth consequences. First event was associated with poor geo-magentic storm disturbance index (Dst, -30 nT) value and second event associated with intense Dst value of around -119 nT. Initial sunspot and its earlier evolution are observed by Helioseismic and Magnetic Imager (HMI). Eruption signatures from solar source region are confirmed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) at different wavelength observations and Aryabhatta Research Institute of Observational Sciences (ARIES) Hα filtergrams. For both the CMEs, original eruption were associated with M1.1 class of flares and were followed by moderate speed coronal mass ejections. At the solar source region of the eruptions, we observed circular ribbon flare (CRF) for both the cases, suggesting fan-spine magnetic configuration in the active region corona. The circular ribbons were situated at the leading part of the ARs. The multi-channel SDO observations confirm that the eruptive flares and subsequent CMEs were intimately related to the filament eruption. After the flares, we observed moderate speed CMEs in Large Angle Spectrometric Coronograph (LASCO) field of view (FOV) with linear speed of 671 and 631 km/s , respectively. Same event tracked up to Earth by Solar Terrestrial and Relational Observatory (STEREO) instruments. We find that the source region evolution of CMEs, guided by the large-scale coronal magnetic field configuration, along with near-Sun propagation characteristics, such as, CME-CME interactions, played important roles in deciding the evolution of CMEs in the interplanetary medium and subsequently their geo-effectiveness.

About Speaker :

 

Dr. Syed Ibrahim is a PDF in ARIES.