Flare parameters inferred from a 3D loop model database

Cuambe, V. A., Costa, J.E.R. and Simoes, P.J.A. (2018) Flare parameters inferred from a 3D loop model database. Monthly Notices of the Royal Astronomical Society, 477(2), pp. 1508-1519. (doi: 10.1093/mnras/sty867)

Abstract

We developed a data base of pre-calculated flare images and spectra exploring a set of parameters which describe the physical characteristics of coronal loops and accelerated electron distribution. Due to the large number of parameters involved in describing the geometry and the flaring atmosphere in the model used, we built a large data base of models (∼250 000) to facilitate the flare analysis. The geometry and characteristics of non-thermal electrons are defined on a discrete grid with spatial resolution greater than 4 arcsec. The data base was constructed based on general properties of known solar flares and convolved with instrumental resolution to replicate the observations from the Nobeyama radio polarimeter spectra and Nobeyama radioheliograph (NoRH) brightness maps. Observed spectra and brightness distribution maps are easily compared with the modelled spectra and images in the data base, indicating a possible range of solutions. The parameter search efficiency in this finite data base is discussed. 8 out of 10 parameters analysed for 1000 simulated flare searches were recovered with a relative error of less than 20 per cent on average. In addition, from the analysis of the observed correlation between NoRH flare sizes and intensities at 17 GHz, some statistical properties were derived. From these statistics, the energy spectral index was found to be δ ∼ 3, with non-thermal electron densities showing a peak distribution ⪅107 cm−3, and Bphotosphere ⪆ 2000 G. Some bias for larger loops with heights as great as ∼2.6 × 109 cm, and looptop events were noted. An excellent match of the spectrum and the brightness distribution at 17 and 34 GHz of the 2002 May 31 flare is presented as well.

• Item Type: Articles
• Additional Information: We would like to thank the SKA SA for all their support and the Brazilian agency CAPES for providing financial support for one of the authors (V.A.C). Finally, we are grateful to FAPESP for the partial financial support through the grant 2014/11156-4 for the computing infrastructure.
• Keywords: Space and planetary science, astronomy and astrophysics
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Simoes, Dr Paulo
• Authors: Cuambe, V. A., Costa, J.E.R., and Simoes, P.J.A.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Monthly Notices of the Royal Astronomical Society
• Publisher: Oxford University Press
• ISSN: 0035-8711
• ISSN (Online): 1365-2966
• Published Online: 06 April 2018
• Copyright Holders: Copyright © 2018 The Authors
• First Published: First published in Monthly Notices of the Royal Astronomical Society 477(2):1512-1527
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher