INTER-UNIVERSITY  CENTRE  FOR  ASTRONOMY  AND  ASTROPHYSICS
(An Autonomous Institution of the University Grants Commission)

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  SEMINAR

 

DR. DEBI PRASAD CHOUDHARY

California State University, Northridge
 
Photospheric and Chromospheric Properties of the Umbral and Penumbral Fibril Loops
 
 

Mass and energy exchange between the sunspot and its surroundings is not only key in understanding the stability and decay of these objects but also important for detecting the origin of several dynamic events. The two dominant flows that occur around the sunspots are photospheric Evershed flow and chromospheric inverse-Evershed flow along penumbral and super-penumbral loops respectively, that could be governed by siphon-flow or magnetoconvection mechanisms. Our extensive observational study of these phenomena using spectropolarimeters at Dunn Solar Telescope in FeI 630.2 nm, CaI 854.2 nm and He1083 nm, show interesting thermodynamic structure along the loops. Yet, the foot-point properties, that are key to understand the origin of these mass motion, are not known specially due to the limited spatial resolution. Our goal is to use MAST observations of penumbral and super-penumbral loops in photospheric and chromospheric spectral lines at FeI 630.2 nm and Infrared CaI 854.2 nm respectively, spectropolarimeters to measure thermodynamic parameters such as velocity, temperature and also magnetic field of these locations.

 
IUCAA Lecture Hall, Bhaskara 3
July 4, 2018, 16:00 hrs.