1. Self-Organized Criticality in Magnetic Substorms Understanding The Mechanics of Space Weather

2. Solar Weather Terms Coronal Mass Ejections (CMEs) Solar Wind Magnetosphere Magnetic Reconnection Van Allen Radiation Belts Ring Current Disturbance Storm Time (DST)

3. Necessity for Understanding DST Ring Current field capable of inducing large currents in power lines, satellites, computer chip factories etc. Source (left): http://optics.org/objects/ole_feat/ Source (right): www.physics.co.il/News.asp

4. Coronal Mass Ejections Solar blob of electrified gas Occurrence: Solar Minimum: ~ 1 CME per week Solar Maximum: 2-3 per day Source: http://www.spacescience.org/ExploringSpace/VirtualExhibit/SpaceIsNotEmpty/

5. Magnetosphere Source (bottom): http://istp.gsfc.nasa.gov/istp/news/img.html Source (top): www.spaceweather.com/aurora/ images/31mar01/haug1.jpg Dipole Magnetic Field Protects earth, deflecting solar activity Causes particles to spiral into atmosphere at poles (aurora)

6. Solar Wind & Magnetosphere Source (above): http://istp.gsfc.nasa.gov/istp/news/img.html Source (left):http://www-istp.gsfc.nasa.gov/Education/wsolwind.html

7. Magnetic Reconnection Occurs during loading phase of cycle (typically 40 minutes) Magnetosphere tail becomes severely stretched Magnetic field lines become aligned anti-parallel Field cancels, energy conserved in several ways including injection of energetic particles Plasmoid drifts off with solar wind

8. Magnetic Reconnection Source: http://istp.gsfc.nasa.gov/istp/news/img.html

9. Magnetic Reconnection Source: http://istp.gsfc.nasa.gov/istp/news/img.html

10. Van Allen Belt & Ring Current Drift of energetic particles Production of “Ring Current” in belt, radius 2R E (Earth Radius) Current produces own field interacting with magnetosphere Source: http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0010420.html

11. DST - Description Disturbance Storm Time index Measures strength of ring current field based on interaction with earth’s magnetosphere Measured in units of nanoTesla (nT)

12. DST – Scatterplot (2001) DST Index value (nT) Time (Hours)

13. DST – Probability Distribution Probability DST Index value (nT)

14. DST – Periodicities Power Spectral Density Peaks Corresponds to 27.12 days

15. Self Organized Criticality (SOC) Statistical analysis, independent of time Event based, critical climax and relaxing Classic example: Avalanches in a sand pile Source: http://www.londontoday.net/photo/industry/v001/images/full/

16. Power Laws in SOC Event Size vs Number of Events; straight line in log-log space lnN(s) = -  * ln(s) N(s) = s -  Events of a bigger size should occur less frequently than events of a smaller size

17. DST – A SOC System ln(size of event) ln(number of occurrences) T=0.6923

18. Use for SOC Model Precursors for magnetic reconnection discovered, severity of substorm can be determined Ability to predict length of an event based on initial size of storm?

19. Source: http://www.spacescience.org/ExploringSpace/VirtualExhibit/SpaceIsNotEmpty/