Author ORCID Identifier
James McAteer:
https://orcid.org/0000-0003-1493-101X
Shaun Bloomfield:
https://orcid.org/0000-0002-4183-9895
Document Type
Journal Article
Journal Article Version
Final Version / Publisher's PDF (peer-reviewed)
Publication Date
10-20-2013
Abstract
We carry out a novel statistical test of the Neupert effect based on multifractal spectra. The multifractal spectrum is the number distribution of the strengths (i.e., the Holder exponents) of bursts in a signal. This is tested on simulations and carried out on RHESSI X-ray data from a well observed GOES X4.8 magnitude flare. The multifractal spectra is ideally suited to quantifying the relative smooth and bursty signals typically found in (thermal) soft X-ray and (non-thermal) hard X-ray data of solar flares. We show that light curves from all energies between 3 keV and 25 keV are statistically similar, suggesting that all these signals are dominated by the same (presumably thermal) emission. Emission lying between 25 keV and 100 keV probably contains some contribution from both thermal and non-thermal sources. The multifractal spectrum of a signal and that of its (cumulative) temporal integration are statistically similar (i.e., low residuals upon subtraction), but shifted by one in the peak Holder exponent. We find the pairs of 3-6 keV and 100-300 keV emissions, the 6-12 keV and 100-300 keV emissions and the 12-25 keV and 100-300 keV emissions are all consistent with the Neupert effect. The best agreement with the Neupert effect is between the 12-25 keV and 100-300 keV pair, although possibly with some secondary source of thermal emission present.
Published in
Astrophysical Journal
DOI
10.1088/0004-637X/776/2/66
Keywords
Sun: activity, Sun: flares, methods: statistical
Department / Organizational Unit
Astronomy
Copyright Notice
© 2013 R. McAteer & D. Bloomfield, reuse allowed according to Creative Commons license.
License for Reuse
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
McAteer, R. T. J., & Bloomfield, D. S. (2013). The bursty nature of solar flare X-ray emission. II. The Neupert effect. Astrophysical Journal, 776(2). https://doi.org/10.1088/0004-637X/776/2/66