caa a22 4500 445346973 CHVBK 20180317142831.0 cr unu---uuuuu 170323e20111201xx s 000 0 eng 10.1007/s11207-011-9755-0 doi (NATIONALLICENCE)springer-10.1007/s11207-011-9755-0 Aschwanden Markus Solar and Astrophysics Laboratory, Dept. ADBS, Lockheed Martin Advanced Technology Center, Bldg.252, 3251 Hanover St., 94304, Palo Alto, CA, USA aut The State of Self-organized Criticality of the Sun During the Last Three Solar Cycles. I. Observations [Elektronische Daten] [Markus Aschwanden] We analyze the occurrence-frequency distributions of peak fluxes [P], total fluxes [E], and durations [T] of solar flares over the last three solar cycles (during 1980 - 2010) from SMM/HXRBS, CGRO/BATSE, and RHESSI hard X-ray data. From the synthesized data we find powerlaw slopes with mean values of α P =1.73±0.07 for the peak flux, α E =1.62±0.12 for the total flux, and α T =1.99±0.35 for flare durations. We find a tendency of an anti-correlation of the powerlaw slope of peak fluxes with the flare rate or sunspot number as a function of the solar cycle. The occurrence powerlaw slope is always steeper by Δα≈0.1 during a solar-cycle minimum compared with the previous solar-cycle maximum, but the relative amplitude varies for each cycle or instrument. Since each solar cycle has been observed with a different instrument, part of the variation could be attributed to instrumental characteristics and different event selection criteria used in generating the event catalogs. The relatively flatter powerlaw slopes during solar maxima could indicate more energetic flares with harder electron-energy spectra, probably due to a higher magnetic complexity of the solar corona. This would imply a non-stationarity (or solar-cycle dependence) of the coronal state of self-organized criticality. Springer Science+Business Media B.V., 2011 Sun: hard X-rays nationallicence Sun: flares nationallicence Solar cycle nationallicence Solar Physics Springer Netherlands 274/1-2(2011-12-01), 99-117 0038-0938 274:1-2<99 2011 274 11207 https://doi.org/10.1007/s11207-011-9755-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11207-011-9755-0 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Aschwanden Markus Solar and Astrophysics Laboratory, Dept. ADBS, Lockheed Martin Advanced Technology Center, Bldg.252, 3251 Hanover St., 94304, Palo Alto, CA, USA aut NATIONALLICENCE 773 0- Solar Physics Springer Netherlands 274/1-2(2011-12-01), 99-117 0038-0938 274:1-2<99 2011 274 11207 Metadata rights reserved Springer special CC-BY-NC licence nationallicence SWISSBIB 445346795 BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer