1. Sparkling EUV bright dots observed with Hi-C
- Author
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Regnier, S., Alexander, C. E., Walsh, R. W., Winebarger, A. R., Cirtain, J., Golub, L., Korreck, K. E., Mitchell, N., Platt, S., Weber, M., De Pontieu, B., Title, A., Kobayashi, K., Kuzin, S., and DeForest, C. E.
- Subjects
Astrophysics - Solar and Stellar Astrophysics - Abstract
Observing the Sun at high time and spatial scales is a step towards understanding the finest and fundamental scales of heating events in the solar corona. The Hi-C instrument has provided the highest spatial and temporal resolution images of the solar corona in the EUV wavelength range to date. Hi-C observed an active region on 11 July 2012, which exhibits several interesting features in the EUV line at 193\AA: one of them is the existence of short, small brightenings ``sparkling" at the edge of the active region; we call these EUV Bright Dots (EBDs). Individual EBDs have a characteristic duration of 25s with a characteristic length of 680 km. These brightenings are not fully resolved by the SDO/AIA instrument at the same wavelength, however, they can be identified with respect to the Hi-C location of the EBDs. In addition, EBDs are seen in other chromospheric/coronal channels of SDO/AIA suggesting a temperature between 0.5 and 1.5 MK. Based on their frequency in the Hi-C time series, we define four different categories of EBDs: single peak, double peak, long duration, and bursty EBDs. Based on a potential field extrapolation from an SDO/HMI magnetogram, the EBDs appear at the footpoints of large-scale trans-equatorial coronal loops. The Hi-C observations provide the first evidence of small-scale EUV heating events at the base of these coronal loops, which have a free magnetic energy of the order of 10$^{26}$ erg., Comment: 10 pages, 13 figures (figure 1 at low resolution), in press
- Published
- 2014
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