Statistical characterisation of full-disk EUV/XUV solar irradiance and correlation with solar activity
Abstract
We investigate the distribution of fluctuations in solar irradiance when integrated over the full disk, obtained using extreme ultraviolet/soft X-ray observations from the SOHO CELIAS/SEM instrument. This time series sums over both the contributions of single distinguishable flares, and of many other processes. By detrending we select events with timescales of less than a few hours such as waves, slow flows, and CMEs. The statistics generated by this range of phenomena can be characterised by power-law-tailed distributions. We show that (i) during the high-activity period 2000 Jan-June the tail exponent a(T)=1.5 +/- 0.1; (ii) during the low-activity period 1996 Jan-June a(T)=3.0 +/- 0.2; and (iii) in general a(T) decreases with increasing activity.
Cite
@article{arxiv.astro-ph/0302277,
title = {Statistical characterisation of full-disk EUV/XUV solar irradiance and correlation with solar activity},
author = {J. Greenhough and S. C. Chapman and R. O. Dendy and V. M. Nakariakov and G. Rowlands},
journal= {arXiv preprint arXiv:astro-ph/0302277},
year = {2009}
}
Comments
4 pages, 5 figures; v.2 R-squared goodness of fits added