Evidence for power-law distributions of total EUV/XUV solar irradiance that correlate with solar activity
نویسندگان
چکیده
The identification of flares in solar datasets implies using a thresholding process which excludes the majority of low-emission regions. In this paper we investigate a different measure of solar emission: the distribution of the total solar irradiance when integrated over the disk, obtained using extreme ultraviolet/soft X-ray observations from the SOHO CELIAS/SEM instrument. We show that during the high activity period 2000 Jan– June, the distribution is consistent with a power-law tail of index aT = 1.5± 0.1, whereas during the low activity period 1996 Jan–June we find aT = 2.9 ± 0.2. These results provide model-independent evidence for changes in the global characteristics of solar irradiance, and complement existing studies of flare intensity distributions.
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