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25 Years of Self-organized Criticality: Concepts and Controversies
Space Science Reviews, (28.05.2015)
DOI: 10.1007/s11214-015-0155-x
Аннотация
Introduced by the late Per Bak and his colleagues, self-organized criticality
(SOC) has been one of the most stimulating concepts to come out of statistical
mechanics and condensed matter theory in the last few decades, and has played a
significant role in the development of complexity science. SOC, and more
generally fractals and power laws, have attacted much comment, ranging from the
very positive to the polemical. The other papers in this special issue
(Aschwanden et al, 2014; McAteer et al, 2014; Sharma et al, 2015) showcase the
considerable body of observations in solar, magnetospheric and fusion plasma
inspired by the SOC idea, and expose the fertile role the new paradigm has
played in approaches to modeling and understanding multiscale plasma
instabilities. This very broad impact, and the necessary process of adapting a
scientific hypothesis to the conditions of a given physical system, has meant
that SOC as studied in these fields has sometimes differed significantly from
the definition originally given by its creators. In Bak's own field of
theoretical physics there are significant observational and theoretical open
questions, even 25 years on (Pruessner, 2012). One aim of the present review is
to address the dichotomy between the great reception SOC has received in some
areas, and its shortcomings, as they became manifest in the controversies it
triggered. Our article tries to clear up what we think are misunderstandings of
SOC in fields more remote from its origins in statistical mechanics, condensed
matter and dynamical systems by revisiting Bak, Tang and Wiesenfeld's original
papers.
