Analysis of intermittency in submillimeter radio and hard x-ray data during the impulsive phase of a solar flare

Giménez de Castro, G., Simões, P.J.A. , Raulin, J.-P. and Guimarães Jr., O.M. (2016) Analysis of intermittency in submillimeter radio and hard x-ray data during the impulsive phase of a solar flare. Solar Physics, 291(7), pp. 2003-2016. (doi: 10.1007/s11207-016-0949-3)

Abstract

We present an analysis of intermittent processes occurring during the impulsive phase of the flare SOL2012-03-13, using hard X-rays and submillimeter radio data. Intermittency is a key characteristic in turbulent plasmas and has so far only been analyzed for hard X-ray data. Since in a typical flare the same accelerated electron population is believed to produce both hard X-rays and gyrosynchrotron radiation, we compare the two time profiles by searching for intermittency signatures. For this, we define a cross-wavelet power spectrum, which is used to obtain the local intermittency measure, or LIMLIM. When greater than three, the square LIMLIM coefficients indicate a local intermittent process. The LIM2LIM2 coefficient distribution in time and scale helps to identify avalanche or cascade energy release processes. We find two different and well-separated intermittent behaviors in the submillimeter data: for scales greater than 20 s, a broad distribution during the rising and maximum phases of the emission seems to favor a cascade process; for scales below 1 s, short pulses centered on the peak time are representative of avalanches. When applying the same analysis to hard X-rays, we find that only the scales above 10 s produce a distribution related to a cascade energy fragmentation. Our results suggest that different acceleration mechanisms are responsible for tens of keV and MeV energy ranges of electrons.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Simoes, Dr Paulo
• Authors: Giménez de Castro, G., Simões, P.J.A., Raulin, J.-P., and Guimarães Jr., O.M.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Solar Physics
• Publisher: Springer
• ISSN: 0038-0938
• ISSN (Online): 1573-093X
• Published Online: 19 July 2016
• Copyright Holders: Copyright © 2016 Springer Science+Business Media
• First Published: First published in Solar Physics 291(7): 2003-2016
• Publisher Policy: Reproduced in accordance with the publisher copyright policy