First large-scale statistical search for evidence of pulsations in solar flares
Abstract
The nature of quasi-periodic pulsations in solar flares remains poorly constrained, and the general prevalence of such signals in solar flares is unknown, due to the lack of large-scale studies. Therefore, we perform the first large-scale, statistically robust search for evidence of signals consistent with quasi-periodic pulsations in solar flares, focusing on the 1 - 300 s timescale. We analyse 684 M- and X-class flares observed by GOES in soft X-rays between 2011 February 1 and 2015 December 31. Additionally, we analyse 210 events in the same time interval observed by Fermi/GBM in hard X-rays. Using a model comparison method, we determine whether there is evidence for a substantial enhancement in the Fourier power spectrum that may be consistent with a QPP signature. From this, we determine the fraction of GOES events and Fermi/GBM events showing signatures consistent with classical descriptions of QPP. A further subset of events, particularly in GOES data, show evidence for very broad enhancements in Fourier power. These latter events may be consistent with signatures where the characteristic timescale is substantially evolving over time, or where complex signal behaviour is present. We also show that, for events where a detection occurred in both Fermi/GBM and GOES datasets, similar characteristic timescales were found with both instruments. We discuss the implications of these results for our understanding of solar flares.
- Publication:
-
AAS/Solar Physics Division Abstracts #47
- Pub Date:
- May 2016
- Bibcode:
- 2016SPD....47.0639I