25 Years of Self-Organized Criticality: Solar and Astrophysics

• DOI: 10.1007/s11214-014-0054-6
• Publication Date: 2014-07-14T06:36:02Z
• Authors: Markus J. Aschwanden; Norma B. Crosby; Michaila Dimitrop...; Manolis K. Georgo...; Stefan Hergarten; James McAteer; Alexander V. Milo...; Shin Mineshige; Laura Morales; Naoto Nishizuka; Gunnar Pruessner; Raul Sanchez; A. Surja Sharma; Antoine Strugarek; Vadim Uritsky
• Keywords: Self-organized Criticality; Heliosphere

Shortly after the seminal paper {\sl "Self-Organized Criticality: An explanation of 1/f noise"} by Bak, Tang, and Wiesenfeld (1987), idea has been applied to solar physics, in "Avalanches Distribution Solar Flares"} Lu Hamilton (1991). In following years, an inspiring cross-fertilization from complexity theory astrophysics took place, where SOC concept was initially flares, stellar magnetospheric substorms, later extended radiation belt, heliosphere, lunar craters, asteroid Saturn ring, pulsar glitches, soft X-ray repeaters, blazars, black-hole objects, cosmic rays, boson clouds. The application concepts performed numerical cellular automaton simulations, analytical calculations statistical (powerlaw-like) distributions based on physical scaling laws, observational tests theoretically predicted size waiting time distributions. Attempts have undertaken import models into toy models, such as discretization magneto-hydrodynamics (MHD) processes. novel applications stimulated also vigorous debates about discrimination between SOC-like, non-SOC processes, phase transitions, turbulence, random-walk diffusion, percolation, branching network theory, chaos fractality, multi-scale, other phenomena. We review studies last 25 years highlight new trends, open questions, future challenges, discussed during two recent ISSI workshops this theme.