STATISTICAL PROPERTIES OF SOLAR FLARES AND COMPARISON TO OTHER IMPULSIVE ENERGY RELEASE EVENTS

2009 ◽  
Vol 23 (28n29) ◽  
pp. 5609-5618 ◽  
Author(s):  
FABIO LEPRETI ◽  
VLADIMIR G. KOSSOBOKOV ◽  
VINCENZO CARBONE
Keyword(s):  
Solar Flare ◽  
Energy Release ◽  
Solar Flares ◽  
Statistical Properties ◽  
Universal Curve ◽  
Mhd Turbulence ◽  
Natural Systems ◽  
Self Organized ◽  
Self Organized Criticality ◽  
Impulsive Processes

Impulsive energy release events are observed in many natural systems. Solar flares are certainly among the most remarkable examples of such processes. In the last years the study of solar flare statistical properties has received considerable attention in the context of solar flare models based on different approaches, such as Self Organized Criticality (SOC) or magnetohydrodynamic (MHD) turbulence. In this talk the main statistical properties of solar flares will be presented and compared to those of other well known impulsive processes, such as earthquakes and soft γ-ray flashes occurring on neutron stars. It is shown that the these phenomena are characterized by different statistics that cannot be rescaled onto a single, universal curve and that this holds even for the same phenomenon, when observed in different periods or at different locations. Our results indicate apparent complexity of impulsive energy release processes, which neither follow a common behavior nor could be attributed to a universal physical mechanism.

scholarly journals Do the solar flares originating from an individual active region follow a random process or a memory-dependent correlation?

2020 ◽  
Vol 494 (1) ◽  
pp. 975-982
Author(s):  
W H Lei ◽  
C Li ◽  
F Chen ◽  
S J Zhong ◽  
Z G Xu ◽  
...  
Keyword(s):  
Active Region ◽  
Random Process ◽  
Waiting Time ◽  
Solar Flares ◽  
Three Dimensional ◽  
Mhd Turbulence ◽  
Self Organized ◽  
Self Organized Criticality ◽  
Cycle 24 ◽  
Non Linear System

ABSTRACT We investigate the waiting time statistics of solar flares both in a flare-productive active region (AR 12673) of the solar cycle 24 and in a three-dimensional magnetohydrodynamic (MHD) simulated AR. The statistical models of a discrete random process and a continuous memory-dependent process are applied to interpret the waiting time distributions (WTDs) of solar flares. Our results indicate that the occurrence of a solar flare in an individual AR maintains a certain amount of memory, and probably arises from MHD turbulence rather than from intermittent avalanches in a self-organized criticality system. It differs from the occurrence of ‘super flares’ when treating the star/Sun as a single non-linear system.

scholarly journals Associating an Entropy with Power-Law Frequency of Events

Entropy ◽  
2018 ◽  
Vol 20 (12) ◽  
pp. 940 ◽  
Author(s):  
Evaldo Curado ◽  
Fernando Nobre ◽  
Angel Plastino
Keyword(s):  
Information Theory ◽  
Forest Fires ◽  
Ground State ◽  
State Energy ◽  
Power Laws ◽  
Natural Systems ◽  
Self Organized ◽  
Self Organized Criticality ◽  
Isothermal Processes ◽  
Entropic Index

Events occurring with a frequency described by power laws, within a certain range of validity, are very common in natural systems. In many of them, it is possible to associate an energy spectrum and one can show that these types of phenomena are intimately related to Tsallis entropy S q . The relevant parameters become: (i) The entropic index q, which is directly related to the power of the corresponding distribution; (ii) The ground-state energy ε 0 , in terms of which all energies are rescaled. One verifies that the corresponding processes take place at a temperature T q with k T q ∝ ε 0 (i.e., isothermal processes, for a given q), in analogy with those in the class of self-organized criticality, which are known to occur at fixed temperatures. Typical examples are analyzed, like earthquakes, avalanches, and forest fires, and in some of them, the entropic index q and value of T q are estimated. The knowledge of the associated entropic form opens the possibility for a deeper understanding of such phenomena, particularly by using information theory and optimization procedures.

scholarly journals Preface

1991 ◽  
Vol 336 (1643) ◽  
pp. 323-323
Keyword(s):  
Solar Flare ◽  
Energy Release ◽  
Gamma Rays ◽  
Solar Flares ◽  
Solar Maximum ◽  
Interplanetary Space ◽  
Release Site ◽  
Solar Maximum Mission ◽  
New Information ◽  
Three Space

During the period of the 1980 solar maximum three space missions (P78-1, Solar Maximum Mission and Hinotori ) carried out extensive studies of solar flares. In their different ways all of these missions contributed significant new information to our understanding of the solar flare phenomenon. In this volume the contribution made by these three spacecraft to the study of the energy release and the related creation of high-tem perature plasma, the transport of energy from the primary release site, the production of gamma-rays at energies up to 10 MeV and the ejection of solar matter into interplanetary space are reviewed.

Alfvénic Fronts and the turning-off of the Energy Release in Solar Flares

1994 ◽  
Vol 11 (1) ◽  
pp. 25-27 ◽  
Author(s):  
M. S. Wheatland ◽  
D. B. Melrose
Keyword(s):  
Solar Flare ◽  
Energy Release ◽  
Flux Tube ◽  
Solar Flares ◽  
Impedance Matching ◽  
Energy Propagation

AbstractThe effect of impulsively turning off the dissipation in an existing model for energy propagation through Alfvénic fronts into the coronal site of energy release in a solar flare is examined. In the optimum case of impedance matching, the flux tube re-stresses on a much longer timescale than it relaxes, suggesting an explanation for the timescales observed in homologous flares.

Self‐organized Criticality from Separator Reconnection in Solar Flares

2000 ◽  
Vol 542 (2) ◽  
pp. 1088-1099 ◽  
Author(s):  
D. W. Longcope ◽  
E. J. Noonan
Keyword(s):  
Solar Flares ◽  
Self Organized ◽  
Self Organized Criticality

scholarly journals Predicting large solar flares with data assimilation

2015 ◽  
Vol 11 (A29B) ◽  
pp. 734-734
Author(s):  
Antoine Strugarek ◽  
Paul Charbonneau
Keyword(s):  
Data Assimilation ◽  
Solar Flares ◽  
Self Organized ◽  
Self Organized Criticality ◽  
Sandpile Models

AbstractWe propose to use a deterministically-driven class of self-organized criticality sandpile models to carry out predictions of the largest, most dangerous, and hardest to predict solar flares.

scholarly journals Self-organized criticality in solar flares: a cellular automata approach

2010 ◽  
Vol 17 (4) ◽  
pp. 339-344 ◽  
Author(s):  
L. F. Morales ◽  
P. Charbonneau
Keyword(s):  
Solar Flares ◽  
Electrical Current ◽  
Power Law Distribution ◽  
Additional Energy ◽  
Self Organized ◽  
Anisotropic Lattice ◽  
Self Organized Criticality ◽  
Released Energy ◽  
The Mean ◽  
Electrical Current Density

Abstract. We give an overview of a novel lattice-based avalanche model that reproduces well a number of observed statistical properties of solar flares. The anisotropic lattice is defined as a network of vertically-connected nodes subjected to horizontal random displacements mimicking the kinks introduced by random motions of the photospheric footpoints of magnetic fieldlines forming a coronal loop. We focus here on asymmetrical driving displacements, which under our geometrical interpretation of the lattice correspond to a net direction of twist of the magnetic fieldlines about the loop axis. We show that a net vertical electrical current density does build up in our lattice, as one would expect from systematic twisting of a loop-like magnetic structure, and that the presence of this net current has a profound impact on avalanche dynamics. The presence of an additional energy reservoir tends to increase the mean energy released by avalanches, and yield a probability distribution of released energy in better agreement with observational inferences than in its absence. Symmetrical driving displacements are in better conceptual agreement with a random shuffling of photospheric footpoint, and yield a power-law distribution of energy release with exponent larger than 2, as required in Parker's nanoflare model of coronal heating. On the other hand, moderate asymmetrical driving generate energy distribution exponents that are similar to those obtained from SOHO EUV observations.

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