C6.2 class flare parameters inferred with a 3D geometry of flare database

We analysed a GOES C6.2 class solar flare that occurred on 27 October 2003 at the heliographic position S20E29. Utilising a database developed from a simplified 3D magnetic loop model, we inferred a set of geometric and physical parameters to characterise the flare.
This model, based on general properties of known solar flares and adjusted for instrument resolution, was used to replicate observations from the Nobeyama Radio Polarimeter (NoRP) spectra and the Nobeyama Radioheliograph (NoRH) brightness maps. We identified a possible range of parameters by comparing observed spectra and brightness distribution maps with modelled counterparts. The analysis involved computing a weighted mean of the one hundred best-fit model parameters, ranked by increasing χ2 values.Across six discrete time intervals representing the gradual, impulsive, and decay phases of the flare, we observed slight variations in values for ten analysed parameters, with notable exceptions at the burst maxima, including an energy spectral index of approximately 2,34, a photospheric magnetic field strength of around 2 308G, and a non-thermal electron density of about 10^7,11 cm³. In general, our results replicated the soft-hard-soft behaviour in the gradual-peak-decay phases of a solar flare. Therefore, we infer that the physical parameters (magnetic field strength, energy spectral index, and non-thermal electron density) were accurately recovered. However, fitting geometric parameters such as inclination, asymmetry, azimuth, loop radius, loop height, and footpoint separation proved challenging due to the limited resolution of the instruments, which affects the precise determination of loop-like flare geometries.

V. Cuambe[1], J. Costa[2], P. Simões[2]

Type Article

Keywords Sun; Radio radiation; Flares; Magnetic fields; Catalogues

DOI 10.1016/j.asr.2024.06.075

[1] Estação RAEGE de Santa Maria, Associação RAEGE Açores, Santa Maria – Azores, Portugal

[2] Instituto de Pesquisas Espaciais, São José dos Campos-Brasil

[3] Universidade Persbeteriana de Mackenzie, São Paulo – Brasil

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