Self-organized criticality in solar and stellar flares: Are extreme events scale-free ?
Markus J Aschwanden Submitted: 2019-06-13 09:15
We search for outliers in extreme events of statistical
size distributions of astrophysical data sets, motivated
by the Dragon-King hypothesis of Sornette (2009),
which suggests that the most extreme events in a statistical
distribution may belong to a different population, and thus
may be generated by a different phyiscal mechanism, in contrast
to the strict power law behavior of self-organized
criticality (SOC) models. Identifying such disparate outliers
is important for space weather predictions. Possible physical
mechanisms to produce such outliers could be generated by
sympathetic flaring. However, we find that Dragon-King events
are not common in solar and stellar flares, identified in
4 out of 25 solar and stellar flare data sets only.
Consequently, small, large, and extreme flares are essentially
scale-free and can be modeled with a single physical mechanism.
In very large data sets (N > 104) we find significant
deviations from ideal poer laws in almost all data sets.
Neverthess, the fitted power law slopes constrain
physcial scaling laws in terms of flare areas and volumes,
which have the highest nonlinearity in their scaling laws.
Authors: Markus, J. Aschwanden
Publication Status: The Astrophysical Journal (June 13, 2019, accepted), in press
Last Modified: 2019-06-15 17:38