Thermal Characteristics and the Differential Emission Measure Distribution During a B8.3 Flare on 2009 July 4
Abstract
We investigate the evolution of the differential emission measure distribution (DEM[T]) in various phases of a B8.3 flare which occurred on 2009 July 04. We analyze the soft X-ray (SXR) emission in the 1.6-8.0 keV range, recorded collectively by the Solar Photometer in X-rays (SphinX; Polish) and the Solar X-ray Spectrometer (Indian) instruments. We conduct a comparative investigation of the best-fit DEM[T] distributions derived by employing various inversion schemes, namely, single Gaussian, power-law functions and a Withbroe-Sylwester (W-S) maximum likelihood algorithm. In addition, the SXR spectrum in three different energy bands, that is, 1.6-5.0 keV (low), 5.0-8.0 keV (high), and 1.6-8.0 keV (combined), is analyzed to determine the dependence of the best-fit DEM[T] distribution on the selection of the energy interval. The evolution of the DEM[T] distribution, derived using a W-S algorithm, reveals multi-thermal plasma during the rise to the maximum phase of the flare, and isothermal plasma in the post-maximum phase of the flare. The thermal energy content is estimated by considering the flare plasma to be (1) isothermal and (2) multi-thermal in nature. We find that the energy content during the flare, estimated using the multi-thermal approach, is in good agreement with that derived using the isothermal assumption, except during the flare maximum. Furthermore, the (multi-) thermal energy estimated while employing the low-energy band of the SXR spectrum results in higher values than that derived from the combined energy band. On the contrary, the analysis of the high-energy band of the SXR spectrum leads to lower thermal energy than that estimated from the combined energy band.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2016
- DOI:
- 10.3847/0004-637X/823/2/126
- arXiv:
- arXiv:1604.01935
- Bibcode:
- 2016ApJ...823..126A
- Keywords:
-
- plasmas;
- radiation mechanisms: thermal;
- Sun: corona;
- Sun: flares;
- Sun: X-rays;
- gamma rays;
- techniques: spectroscopic;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Accepted for publication in the ApJ, 12 Figures, 14 Pages