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Upcoming Seminar/Colloqium

Topic:

Insights from studying 3D evolution of CMEs in the inner and outer corona and imprint of source regions

Speaker : Satabdwa Majumdar
Affiliation : Indian Institute of Astrophysics, Bangalore
Date & Time :
Venue : Zoom meeting space
Abstract :

Despite studying Coronal Mass Ejections (CMEs) for several years, we are yet to have a clear understanding of their kinematics, especially in the inner corona (< 3R_Sun). Major shortcomings in our present understanding of CME kinematics are due to lack of information in the inner corona, discrepancies due to projection effects and inconsistencies arising from combining white light and Extreme ultra-Violet observations. We stitch together these missing links in our understanding and study the 3D kinematic profiles of 59 slow and fast CMEs by implementing the GraduatedCylindrical Shell (GCS) model to the pair of COR-1 and COR-2 coronagraph images on-board STEREO-A/B. By combining the 3D acceleration and angular width evolution profiles, we found observational evidence on the fact that it is Lorentz force that is responsible for both translating and expanding a CME in its initial heights. Further, we find that the height of influence of the Lorentz force, statistically tend to lie in the range of 2.5-3 RSun. A distribution of peak 3D speeds and accelerations showed that the long tail towards high speeds and accelerations are predominantly contributed by the CMEs coming from ARs. Also, from a study of the acceleration magnitude and the acceleration duration, besides finding a clear anti-correlation between the two quantities, we also found clear signatures of CMEs connected to quiescent prominences (PEs) to be mostly gradual events whereas the ones connected to ARs are mostly impulsive events.

About Speaker :

Satabdwa Majumdar is senior research fellow in the Indian Institute of Astrophysics, working under the guidance of Prof. Dipankar Banerjee.