Probing nanoflare heating with X-ray variability of coronal loops
Abstract
The concept that solar corona is heated by numerous small flare-like events (nanoflares) is considered. Thus, a hot coronal loop is viewed as an ensemble of high temperature elementary filaments created within the coronal magnetic field by random impulsive heating events. The integral parameters of the loop (thermal energy, emission measure, filling factor etc.) obey scaling laws (Vekstein and Katsukawa, 2000), which are determined only by its global energy balance. They are not sensitive to specific details of the heating process such as the energy of an individual heating event, and the energy spectral index of nanoflares. To probe the latter, we analyse variability of the nanoflare heated loops. The aim is to find out how the imposed power-law spectrum of heating events translates into fluctuations in the thermal energy and emission measure of the loop, which can be detected observationally as X-ray and EUV brightenings. It was found that the numerically simulated spectrum of these fluctuations comprises of two separate components. For large intensities the spectral index is close to that imposed for nanoflares, mirroring individual heating events with high energy. At lower intensities fluctuations have a noise-like nature generated by interference of several small nanoflares.
- Publication:
-
Solspa 2001, Proceedings of the Second Solar Cycle and Space Weather Euroconference
- Pub Date:
- March 2002
- Bibcode:
- 2002ESASP.477..123J
- Keywords:
-
- Solar Corona: Heating;
- Solar Coronal Loops