Accumulation of accelerated electrons in coronal loops and time delays of solar flare nonthermal emission

• Published in: Geomagnetism and Aeronomy Vol. 55; no. 7; pp. 979 - 982
• Main Authors: Tsap, Yu. T., Stepanov, A. V., Kopylova, Yu. G.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.12.2015; Springer Nature B.V
• Subjects: Computational fluid dynamics; Coronal loops; Diffusion; Earth and Environmental Science; Earth Sciences; Electrons; Flares; Geophysics/Geodesy; Pitch angle; Pulsation; Solar flares; Solar physics; Time delay; Turbulence; X-rays; Flare; Pitch Angle; Coronal Loop; Magnetic Trap; Accelerate Electron
• ISSN: 0016-7932; 1555-645X; 0016-7940
• DOI: 10.1134/S0016793215070269

The mechanisms by which accelerated electrons accumulate in flare loops with regard to the observed time delays between peaks of prolonged (≫1 s) hard X-ray pulses with different energies are considered. The focus is on an analysis of electron pitch-angle scattering by background plasma particles and/or turbulent pulsations in extreme cases of frequent and rare collisions. It was shown that it is difficult to explain the origination of time delays in the scope of a diffusion model when the electron free path length ( l ) in the corona is smaller than the flare loop length ( L ). The accumulation of energetic particles in loops at l > L is related to a trap-plus-precipitation model in which the regime of weak pitch angle diffusion of trapped electrons in the loss cone predominates.