25 Years of Self-Organized Criticality: Solar and Astrophysics

Markus J. Aschwanden, Norma B. Crosby, Michaila Dimitropoulou, Manolis K. Georgoulis, Stefan Hergarten, James McAteer, Alexander V. Milovanov, Shin Mineshige, Laura Morales, Naoto Nishizuka, Gunnar Pruessner, Raul Sanchez, A. Surja Sharma, Antoine Strugarek, Vadim Uritsky

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Shortly after the seminal paper “Self-Organized Criticality: An explanation of 1/fnoise” by Bak et al. (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.
Original languageEnglish
Pages (from-to)47 - 166
Number of pages120
JournalSpace Science Reviews
Issue number1-4
Publication statusPublished - 1 Jan 2016
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Aschwanden, M. J., Crosby, N. B., Dimitropoulou, M., Georgoulis, M. K., Hergarten, S., McAteer, J., Milovanov, A. V., Mineshige, S., Morales, L., Nishizuka, N., Pruessner, G., Sanchez, R., Sharma, A. S., Strugarek, A., & Uritsky, V. (2016). 25 Years of Self-Organized Criticality: Solar and Astrophysics. Space Science Reviews, 198(1-4), 47 - 166. https://doi.org/10.1007/s11214-014-0054-6