Self-Organized Criticality and Turbulence 1 st ISSI Team Meeting Introduction

1. Self-Organized Criticalityand Turbulence 1st ISSI Team MeetingIntroduction Team Coordinator: Markus J. Aschwanden 2012 October 15-19 International Space Science Institute (ISSI) Hallerstrasse 6, Bern, Switzerland http://www.issibern.ch/teams/s-o-turbulence/index.html

2. Introduction: • SOC ISSI Team Members • Program of Meeting • Interdisciplinary Aspects • Scope and Goal of Meeting

5. Interdisciplinary aspect Solar Physics Social Sciences Astrophysics Self-Organized Criticality Systems Magnetospheric Physics Biophysics Geophysics

6. Interdisciplinary aspects: • SOC occurs in many different physical systems ! • What properties of SOC are common in all physical systems? • Are there statistical aspects that are universal in all systems? • Are there universal parameters (fractal dimensions, powerlaw slopes) ? • Where does the physics play a role (scaling laws of physical parameters)? • Can we come up with a SOC theory that includes both universal • statistical aspects and the physical scaling laws of a particular system?

7. What is Self-Organized Criticality ?

8. Original idea of SOC; • Bak, Tang, & Wiesenfeld (1987) • Norvegian rice pile • Experiment • Powerlaw distribution • of rice avalanche sizes • with slope a=2.04 • (Frette et al. 1996)

9. SOC in Human Activities Zanette 2008 • Urban growth, city sizes • Word frequency in language • Cotton prices • Stock market • Traffic jams • War casualties • Social networks, internet traffic

10. SOC in Biophysics Sepkovski 1993 • Evolution and extinctions • Neuron firing in brain • Neural reverberations of spiking nerve cells • Learning and memory • Breathing in lung, heart rate • Epileptic seizures • Spreads of diseases, measles epidemics • Flying formation of birds

11. SOC in Geophysics Turcotte 1999 • Earthquakes • Landslides • Turbidite depositions • Volcanic eruptions • Snow avalanches • Rainfall, river fluctuations • Cloud formation, climate fluctuations • Forest fires

12. SOC in Magnetospheric Physics • Magnetotail current disruptions • Substorm current disruptions • Bursty bulk flow events • Magnetotail magnetic field fluctuations • Auroral UV and optical images • Auroral electron jet index (AE) Lui et al. 2000

13. SOC in Planetary Physics Cross (1996) – Mare Tranquillitatis (Ranger 8) • Saturn’s rings • Asteroid belt • Lunar craters

14. SOC in Solar Physics Dennis (1985), Crosby et al. (1993) • Solar flare, microflares, nanoflares • Flare gamma rays, hard X-rays, soft X-rays • Flare ultraviolet, EUV, H-alpha • Solar energetic particle events (SEP) • Coronal mass ejections • Solar wind fluctuations

15. SOC in Stellar Physics • Stellar flares (dME stars) • Cataclysmic Variable (CV) stars • Accretion disks • Black holes • Pulsar glitches • Soft gamma repeaters (SGR) Audard et al. (2000)

16. SOC in Galactic Physics and Cosmology • Active galactic nuclei (AGNs) • Blazars • Interstellar medium formation • Galactic spiral structure, elliptical galaxy formation • Interstellar magnetic field, starbursts • Cosmology, big-bang, (multiple ?) inflations

17. 2D Cellular Automaton – Avalanche Event #1628 • Dimension: 2D • Lattice grid: 64 x 64 • Initiation: tSOC=4 x 107 time steps • (to develop SOC state) • Largest avalanche #1628 after tSOC • Starting point: (x=41, y=4) • Duration: T=712 time steps • Peak energy dissipation rate P=2300 • Total energy: E=5 x 105 • Note: • Diffusive boundary increase x(t) • Fractal energy dissipation areas a(t) Aschwanden (2012)

19. Goals identified in our ISSI proposal : • Data analysis of statistical datasets of SOC phenomena, • using new and comprehensive data sets: Can we expect new observational results at 2nd ISSI Team meeting in 2013?

21. Goals and problems identified in our ISSI proposal : • Data analysis of statistical datasets of SOC phenomena, • using new and comprehensive data sets • (2) Improve diagnostics of powerlaw-like distributions: • How to identify scaling and universality in experimental • and computational data? (Finite-size effects, variable drivers?) • (3) How to identify and characterize between SOC and • non-SOC mechanisms? (turbulence? network theory?) • (4) What part of SOC phenomena is captured by lattice models • and is there a route to basic theories and first-principle equations?

23. Metrics of Observables, Statistical Distributions and Physical Processes that need to be defined in order to discriminate SOC from non-SOC processes

24. Metrics of Physical Processes vs. Observational Properties Can we refine the metrics ?

25. The fascination of sandpiles ………………