ESWW3 16.11.2006 Bruxelles ,

M. Messerotti & H. Lundstedt 1

Advancing Solar Activity Understanding: The Mutual Role of

Space Weather Activities

M. Messerotti1,2 and H. Lundstedt3

1INAF-Astronomical Observatory of Trieste (Italy)2Dept. of Physics, University of Trieste (Italy)

3Swedish Institute of Space Physics, Lund (Sweden)

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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

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Solar Drivers

M. Messerotti, 2005

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Characteristic Time Scales of Solar Drivers

M. Messerotti, 2005

M. Messerotti, 2005

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Activity Triggers

M. Messerotti, 2005

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Available Modelsfor Solar Drivers

F. Zuccarello, 2005

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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

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Solar Activity: a Manifestation ofCoupled Multi-Scale Processes

FLUIDMOTION

MAGNETICTOPOLOGY

MEDIUMSPATIALSCALE

LARGESPATIALSCALE

SMALLSPATIALSCALE

MEDIUMTIME

SCALE

LONGTIME

SCALE

SHORTTIME

SCALE

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Solar Activity: a Manifestation ofCoupled Multi-Scale Chaotic Processes

FLUIDMOTION

MAGNETICTOPOLOGY

MEDIUMSPATIALSCALE

LARGESPATIALSCALE

SMALLSPATIALSCALE

MEDIUMTIME

SCALE

LONGTIME

SCALE

SHORTTIME

SCALE

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Physical Description of Solar Activity

MAGNETICENERGYBUILD UP

LARGESPATIALSCALE

SMALLSPATIALSCALE

MHD

MHD + KIN

MAGNETICENERGYRELEASE

LARGESPATIALSCALE

SMALLSPATIALSCALE

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Advanced Physical Description of Solar Activity

MAGNETICENERGYBUILD UP

LARGESPATIALSCALE

SMALLSPATIALSCALE

MHD

MHD + KIN

MAGNETICENERGYRELEASE

LARGESPATIALSCALE

SMALLSPATIALSCALE

STOCHASTICITY

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Observational Description of Solar Activity

• Descriptor := Observable

A = A ( s ; t ; E ) A |Rn

with s |R3 (spatial variable)

t |R1 (time variable)

E |Rn (energy variable)

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Characterizing an Active Region

AR

• Morphology Descriptor

M = M ( x, y, z ) Classification

• Magnetic Topology Descriptor

M = M ( x, y, z ) Classification

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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 )

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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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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