Abstract Details

Name: Girjesh R Gupta
Affiliation: IUCAA
Conference ID: ASI2017_530
Title : Heating and cooling of coronal loop observed during a micro-flare with IRIS, SDO, and XRT
Authors and Co-Authors : Aveek Sarkar Physical Research Laboratory Ahmadabad, India
Abstract Type : Oral
Abstract Category : Sun and the Solar System
Abstract : Transient brightenings are small intense brightening found near active region. They last just for few minutes. They can be point-like, or multi-loop in nature. They can reach temperature up to 8 MK and can also have signatures in the cooler 1-2 MK lines. We found one such event from the simultaneous observations of IRIS, SDO, and XRT/Hinode. Both the loop footpoints show sudden intense brightening (active region transient brightening, ARTB, commonly called as micro-flare). After the transient event, loop gets brightened up and temperature of the loop reaches about 8 MK. Using the intensity line ratio of O IV 1399.7/1401.2 ËšA, electron density during the event was found to be around 10^11.8 /cm^3 at one of the footpoints. LOS velocity during the transient becomes 15 km/s whereas line width increases from 35 km/s to 60 km/s with respect to pre-event conditions. Micro-flaring event was recorded in almost all the passbands of AIA/SDO and SJI/IRIS whereas loop brightening was observed only in the hotter channels. Brightness (conduction) front moves from loop foot-point to towards loop-top with the speed around 200 km/s, 70 km/s, and 60 km/s as found from AIA 131 ËšA (10 MK), 94 ËšA (7 MK), and 335 ËšA (4 MK) AIA passbands. All the observables are to be compared with 1-D hydrodynamic model of coronal loops. Detailed study of these observations are under progress.