1. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 1 Advancing Solar Activity Understanding: The Mutual Role of Space Weather Activities M. Messerotti 1,2 and H. Lundstedt 3 1 INAF-Astronomical Observatory of Trieste (Italy) 2 Dept. of Physics, University of Trieste (Italy) 3 Swedish Institute of Space Physics, Lund (Sweden)

2. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 2 Outline of the talk The knowledge on SA relevant to SpW The Sun as a complex system SA as manifestation of coupled multi-scale chaotic processes The characterization of SA Advanced analysis and prediction of SA Conclusions

3. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 3 Solar Drivers M. Messerotti, 2005

4. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 4 Characteristic Time Scales of Solar Drivers M. Messerotti, 2005

5. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 5 Activity Triggers M. Messerotti, 2005

6. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 6 Available Models for Solar Drivers F. Zuccarello, 2005

7. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 7 The Sun as a Complex Plasma System Plasma Global Fluid Motion Global Magnetic Field Differential Fluid Motion Non-axisymmetric Motions Localized Magnetic Fields Global Fluid Motion Large Scale Magnetic Field

8. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 8 Solar Activity: a Manifestation of Coupled Multi-Scale Processes FLUID MOTION MAGNETIC TOPOLOGY MEDIUM SPATIAL SCALE LARGE SPATIAL SCALE SMALL SPATIAL SCALE MEDIUM TIME SCALE LONG TIME SCALE SHORT TIME SCALE

9. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 9 Solar Activity: a Manifestation of Coupled Multi-Scale Chaotic Processes FLUID MOTION MAGNETIC TOPOLOGY MEDIUM SPATIAL SCALE LARGE SPATIAL SCALE SMALL SPATIAL SCALE MEDIUM TIME SCALE LONG TIME SCALE SHORT TIME SCALE

10. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 10 Physical Description of Solar Activity MAGNETIC ENERGY BUILD UP LARGE SPATIAL SCALE SMALL SPATIAL SCALE MHD MHD + KIN MAGNETIC ENERGY RELEASE LARGE SPATIAL SCALE SMALL SPATIAL SCALE

11. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 11 Advanced Physical Description of Solar Activity MAGNETIC ENERGY BUILD UP LARGE SPATIAL SCALE SMALL SPATIAL SCALE MHD MHD + KIN MAGNETIC ENERGY RELEASE LARGE SPATIAL SCALE SMALL SPATIAL SCALE STOCHASTICITY

12. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 12 Observational Description of Solar Activity Descriptor := Observable A = A ( s ; t ; E ) A  |R n with s  |R 3 (spatial variable) t  |R 1 (time variable) E  |R n (energy variable)

13. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 13 Characterizing an Active Region AR Morphology Descriptor M = M ( x, y, z )  Classification Magnetic Topology Descriptor M = M ( x, y, z )  Classification

14. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 14 Characterizing the Evolution of an Active Region AR Formation Process Time evolution of the Morphology Descriptor M = M ( x, y, z ; t ) Time evolution of the Magnetic Topology Descriptor M = M ( x, y, z ; t )

15. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 15 Characterizing the Geoeffectivity of an AR AR Formation Process Morphology Descriptor M = M ( x, y, z ; t )  Precursor(s) Magnetic Topology Descriptor M = M ( x, y, z ; t )  Precursor(s)

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21. ESWW3 16.11.2006 Bruxelles,M. Messerotti & H. Lundstedt 21 Conclusions The complexity of SA is due to: –Stochastic character of processes –Process occurrence at different temporal and spatial scales –Time-space-energy coupling among concurrent physical processes A global model of SA is perhaps impossibile to set up as even localized phenomena occur as outcome of the evolution of the global plasma system One has to rely on the time series analysis of diachronic measurements of descriptors to improve the models for getting reliable forecasts