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The observed powerlaw distributions of solar flare parameters can be interpreted in terms of a nonlinear dissipative system in the state of self-organized criticality (SOC). We present a universal analytical model of a SOC process that is…

Solar and Stellar Astrophysics · Physics 2012-01-13 Markus J. Aschwanden

Self-organized criticality describes a class of dynamical systems that maintain themselves in an attractor state with no intrinsic length or time scale. Fundamentally, this theoretical construct requires a mechanism for instability that may…

Solar and Stellar Astrophysics · Physics 2022-02-02 Adina D. Feinstein , Darryl Z. Seligman , Maximilian N. Günther , Fred C. Adams

The original concept of self-organized criticality (Bak et al.~1987), applied to solar flare statistics (Lu and Hamilton 1991), assumed a slow-driven and stationary flaring rate, which warrants time scale separation (between flare durations…

Solar and Stellar Astrophysics · Physics 2020-01-08 Markus J. Aschwanden

Solar flares are an abrupt release of magnetic energy in the Sun's atmosphere due to reconnection of the coronal magnetic field. This occurs in response to turbulent flows at the photosphere which twist the coronal field. Similar to…

Solar and Stellar Astrophysics · Physics 2018-06-06 Nastaran Farhang , Hossein Safari , Michael S. Wheatland

We study the time evolution of Solar Flares activity by looking at the statistics of quiescent times $\tau_{L}$ between successive bursts. The analysis of 20 years of data reveals a power law distribution with exponent $\alpha \simeq 2.4$…

We investigate the transition to Self Organized Criticality in a two-dimensional model of a flux tube with a background flow. The magnetic induction equation, represented by a partial differential equation with a stochastic source term, is…

High Energy Astrophysical Phenomena · Physics 2015-09-16 Bogdan Danila , Tiberiu Harko , Gabriela Mocanu

We investigate the relevance of {\sl self-organized criticality (SOC)} models in previously published empirical datasets, which includes statistical observations in astrophysics, geophysics, biophysics, sociophysics, and informatics. We…

Instrumentation and Methods for Astrophysics · Physics 2025-05-05 Markus J. Aschwanden , Felix Scholkmann

A new cellular automaton (CA) model is presented for the self-organized criticality (SOC) in recurrent bursts of soft gamma repeaters (SGRs), which are interpreted as avalanches of reconnection in the magnetosphere of neutron stars. The…

High Energy Astrophysical Phenomena · Physics 2014-08-25 Ken'ichiro Nakazato

We search for outliers in extreme events of statistical size distributions of astrophysical data sets, motivated by the {\sl Dragon-King hypothesis} of Sornette (2009), which suggests that the most extreme events in a statistical…

Solar and Stellar Astrophysics · Physics 2019-08-07 Markus J. Aschwanden

A simplified one dimensional grid is used to model the evolution of magnetized plasma flow. We implement diffusion laws similar to those so-far used to model magnetic reconnection with Cellular Automata. As a novelty, we also explicitly…

High Energy Astrophysical Phenomena · Physics 2015-09-10 Tiberiu Harko , Gabriela Raluca Mocanu , Nicoleta Stroia

Compact plasmas, that exist near black-hole candidates and in gamma ray burst sources, commonly exhibit self-organized non-linear behavior. A model that simulates the non-linear behavior of compact radiative plasmas is constructed directly…

Astrophysics · Physics 2009-10-30 Ran Sivron

Solar flares and coronal mass ejections (CMEs), especially the larger ones, emanate from active regions (ARs). With the aim to understand the magnetic properties that govern such flares and eruptions, we systematically survey all flare…

Solar and Stellar Astrophysics · Physics 2017-01-11 Shin Toriumi , Carolus J. Schrijver , Louise K. Harra , Hugh Hudson , Kaori Nagashima

We analyzed the soft X-ray light curves from the {\sl Geostationary Operational Environmental Satellites (GOES)} over the last 37 years (1975-2011) and measured with an automated flare detection algorithm over 300,000 solar flare events…

Solar and Stellar Astrophysics · Physics 2012-07-18 Markus J. Aschwanden , Samuel L. Freeland

The formation and evolution of active regions is an inherently complex phenomenon. Magnetic fields generated at the base of the convection zone follow a chaotic evolution before reaching the solar surface. In this article, we use a 2-D…

Astrophysics · Physics 2009-11-07 L. Vlahos , T. Fragos , H. Isliker , M. Georgoulis

A set-up is introduced which can be superimposed onto the existing solar flare cellular automata (CA) models, and which specifies the interpretation of the model's variables. It extends the CA models, yielding the magnetic field, the…

Astrophysics · Physics 2007-05-23 H. Isliker , A. Anastasiadis , L. Vlahos

Self-organised critical avalanche models are a class of cellular automata that, despite their simplicity, can be applied to the modeling of solar (and stellar) flares and generate robust power-law distributions in event size measures.…

Solar and Stellar Astrophysics · Physics 2024-02-05 Henri Lamarre , Paul Charbonneau , Antoine Strugarek

The observed size distributions of solar and stellar flares is found to be consistent with the predictions of the fractal-diffusive self-organized criticality (FD-SOC) model, which predicts power law slopes with universal constants of…

Solar and Stellar Astrophysics · Physics 2025-03-25 Markus J. Aschwanden , Carolus , J. Schrijver

Cellular automata provide a fascinating class of dynamical systems capable of diverse complex behavior. These include simplified models for many phenomena seen in nature. Among other things, they provide insight into self-organized…

High Energy Physics - Lattice · Physics 2008-02-03 Michael Creutz

The precise physical process that triggers solar flares is not currently understood. Here we attempt to capture the signature of this mechanism in solar image data of various wavelengths and use these signatures to predict flaring activity.…

Solar and Stellar Astrophysics · Physics 2018-03-14 Eric Jonas , Monica G. Bobra , Vaishaal Shankar , J. Todd Hoeksema , Benjamin Recht

Intermittent magnetohydrodynamical turbulence is most likely at work in the magnetized solar atmosphere. As a result, an array of scaling and multi-scaling image-processing techniques can be used to measure the expected self-organization of…

Astrophysics · Physics 2007-05-23 Manolis K. Georgoulis
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