25 Years of Self-Organized Criticality: Solar and Astrophysics
Markus J. Aschwanden Submitted: 2014-03-25 16:18
Shortly after the seminal paper ``Self-Organized
Criticality: An explanation of 1/f noise'' by Bak, Tang, and Wiesenfeld
(1987), the idea has been applied to solar physics, in``Avalanches
and the Distribution of Solar Flares'' by Lu and Hamilton (1991).
In the following years, an inspiring cross-fertilization from complexity
theory to solar and astrophysics took place, where the SOC concept was
initially applied to solar flares, stellar flares, and magnetospheric
substorms, and later extended to the radiation belt, the heliosphere,
lunar craters, the asteroid belt, the Saturn ring,
pulsar glitches, soft X-ray repeaters, blazars, black-hole
objects, cosmic rays, and boson clouds. The application of SOC concepts
has been performed by numerical cellular automaton simulations, by
analytical calculations of statistical (powerlaw-like) distributions
based on physical scaling laws, and by observational tests of theoretically
predicted size distributions and waiting time distributions. Attempts have been
undertaken to import physical models into the numerical SOC toy models,
such as the discretization of magneto-hydrodynamics (MHD) processes.
The novel applications stimulated also vigorous debates about the
discrimination between SOC models, SOC-like, and non-SOC processes,
such as phase transitions, turbulence, random-walk diffusion,
percolation, branching processes, network theory, chaos theory,
fractality, multi-scale, and other complexity phenomena.
We review SOC studies from the last 25 years and highlight new trends,
open questions, and future challenges, as discussed during two recent
ISSI workshops on this theme.
Authors: Aschwanden, M.J., Crosby, N., Dimitropoulou, M., Geogoulis, M.K., Hergarten, S., McAteer, J., Milovanov, A.V., Mineshige, S., Morales, L., Nishizuka, N., Pruessner, G., Sanchez, R., Sharma, S., Strugarek, A., and Uritsky, V.
Publication Status: Space Science Reviews (subm. March 24, 2014)
Last Modified: 2014-03-26 12:35