Vol 22, No 3

Temperature Analysis of Flaring (AR 11283) and Non-flaring (AR 12194) Coronal Loops

Narges Fathalian, Seyedeh Somayeh Hosseini Rad, Nasibeh Alipour, Hossein Safari


Abstract Here, we study the temperature structure of flaring and non-flaring coronal loops, using extracted loops from images taken in six extreme ultraviolet channels recorded by Atmospheric Imaging Assembly/Solar Dynamics Observatory. We use data for loops of an X2.1-class-flaring active region (AR 11283) during 22:10 UT until 23:00 UT, on 2011 September 6; and a non-flaring active region (AR 12194) during 08:00:00 UT until 09:00:00 UT on 2014 October 26. By using the spatially synthesized Gaussian differential emission measure (DEM) forward-fitting method, we calculate the peak temperatures for each strip of the loops. We apply the Lomb–Scargle method to compute the oscillation periods for the temperature series of each strip. The periods of the temperature oscillations for the flaring loops ranged from 7 to 28.4 minutes. These temperature oscillations show very close behavior to the slow-mode oscillation. We observe that the temperature oscillations in the flaring loops started at least around 10 minutes before the transverse oscillations and continue for a long time duration even after the transverse oscillations ended. The temperature amplitudes increased during the flaring time (20 minutes) in the flaring loops. The periods of the temperatures obtained for the non-flaring loops ranged from 8.5 to 30 minutes, but their significances are less (below 0.5) in comparison with the flaring ones (near to one). Hence the detected temperature periods for the non-flaring loops’ strips are less probable in comparison with the flaring ones, and maybe they are just fluctuations. Based on our confined observations, it seems that the flaring loops’ periods show more diversity and their temperatures have wider ranges of variation than the non-flaring ones. More accurate commentary in this respect requires more extensive statistical research and broader observations.


Keywords Sun: flares – Sun: corona – Sun: oscillations – stars: imaging – stars: solar-type

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