Analysis of Intermittency in Submillimeter Radio and Hard X-Ray Data During the Impulsive Phase of a Solar Flare
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- 作者：G. Giménez de Castro ; P. J. A. Simões ; J.-P. Raulin ; O. M. Guimarães Jr.
- 关键词：Hard X ; rays ; Solar flares ; Microwave ; Solar flares ; Intermittency ; Avalanche models ; Wavelets
- 刊名：Solar Physics
- 出版年：2016
- 出版时间：August 2016
- 年：2016
- 卷：291
- 期：7
- 页码：2003-2016
- 全文大小：1,647 KB
- 刊物类别：Physics and Astronomy
- 刊物主题：Physics
Astronomy
Extraterrestrial Physics and Space Sciences
Astrophysics - 出版者：Springer Netherlands
- ISSN：1573-093X
- 卷排序：291
文摘
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 \(\mathit{LIM}\). When greater than three, the square \(\mathit{LIM}\) coefficients indicate a local intermittent process. The \(\mathit{LIM}^{2}\) 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.