Royal Observatory of Belgium




                           Our Dynamic Star



                                          ...
The Sun




Main source of heat and light.

Stability of the Sun – stable Earth conditions at geological scales.

Only for...
Why study the Sun?




The Star presenting all the details of its surface.


Physical laboratory with the conditions impos...
SOHO/EIT

SOHO (Solar and Heliospheric Observatory) — spacecraft to
observe the Sun. Joint ESA-NASa mission.
 launch – 2 d...
SOHO and STEREO


                Continous Extreme Ultraviolet Imaging of the
                  Sun          ORBITS
     ...
SOHO and STEREO

 SOHO and STEREO monitor the solar corona in 4 central
   wavelengths
 corresponding to the different tem...
Outline


Introduction


Presentation of 3 aspects:

   The Sun and “quiet” atmosphere (permanent regime)
   Manifestation...
The Sun: basic characteristics
   Ordinary yellow dwarf , type G2

   Far from the center in the galactic disk of the
   M...
The Multiple solar roles
Gravitational attraction of the planets ( orbits, tides )

Environment determined by solar electr...
The Sun: structure




     The Moving Sun
I
From the core to transition region




             The Moving Sun
Quiet Atmosphere: introduction




Quiet Sun:
   Structures with weak time dependences (weak magnetic fileds)
   Large sol...
The different Faces of the quiet Sun.
4 principal layers:
    Photosphere
    Chromosphere
    Transition region
    Coron...
Quiet photosphere: the granulation
The solar surface is covered by
a pattern constituted by bright
granules separated by t...
Quiet photosphere: the granulation

Developed turbulence:
   At large scales: regime of
   inetrtial convection
   (advect...
Photosphère calme: Points brillants et tubes de flux

Photopspheric Bright Points:

   In the intergranulas
   B concentra...
Magnetic network evolution
  Magnetic fields are in the continuous evolution. Their
  interaction produce coronal heating....
Photosphere: supergranulation

Organisation of the
granulation in the larger
pattern

Mesogranulation:
  Scales: 5000-1000...
Photosphere: faculaes

More hot regions




                          The Moving Sun
The sunspots: proprties
Photospheric dark regions.
Small spots without structure (pores):
    Diameter <2500km
For D >2500...
The sunspots: penumbra
Vertical field in the umbra
Horizontal field in the penumbra
Radial Filaments structure
Continuous ...
Sunspot Dynamics (Dutch Open Telescope)




               The Moving Sun
Sunspots: Magnetic field

Pass point of intensive magnetic
field trough the thin photospheric
layer.
Global dipolar struct...
The sunspots: properties




Lifetime: hours-months
Umbra Temperature: 4000K
   Quiet photosphere (5800K).
Groupes ellonga...
Sunspot Dynamics          (SOHO/MDI)

Intensity




                     The Moving Sun
Magnetic field and sunspots.




The sunspots are associated to intensive magnetic field (black and
white spots on the mag...
The sunspots: Field hierarchy

Young groupes:
    Compact field
Old groupes:
    Dispersive flux
Permanent fields:
    Neu...
Sunspots and activity cycle

The number of sunspots varies with teh
cycle of ~ 11 ans:
   Cycle amplitude (maxima):
      ...
Sunspots and cycle: distribution in latitude (« Batterfly »)

Toward equator during the cycle:
   First spots: at 30° lati...
Solar Dynamo:                     - effect
Ionized solar plasma:
   Plasma movements = large scale currents.
Magnetic fiel...
Solar Dynamo: -effect
Magnetic lines torsion by the solar
rotation, via the Coriolis force.
Convection helicity generates ...
Ascending and torsion of magnetic loops


 B puts pressure on the background medium:
~ B2

Evacuation of plasma in the flu...
The dynamo in movement




        The Moving Sun
Looking at far side of the Sun


       Helio sesimology informs us about the far side of the
       Sun. One can see here...
Waves on the Sun: helioseismology




                   Thousand of acoustic waves parcourent
                   continuo...
Looking IN the Sun




The helioseismology informs us
about Solar interior as well as
about changing structure of
solar ro...
Exterior Atmosphere




 Chromosphere
       and
Transition Region




      The Moving Sun
The chromosphere: general structure

Much more dynamic medium,
that the photosphere

Important spatio/temporal
variations ...
Fine structure fine: the spicules
Surface covered by the vertical spouts (~100 000 on teh
Sun), the spicules:             ...
The chromosphere: heating source
The turbulent photopsheric convection provides energy to heat upper layers.
It produces p...
Atmopsheric Model


Coronal heating problem: why is the corona so hot?




                             Vertical profile o...
Dissipation of magnetic energy & small scales
                                 2 traditional approchaes AC/DC

1. Heating ...
Turbulent cascade to small scales

               Natural mechanism to form small scales

The couplings between waves and ...
Turbulent cascade to small scales
Problems :
   1. Energy flux of waves transformed to particle energy:
                  ...
Experimental Evidence of small scale sources
Krucker & Benz , 1998 (SOHO), Parnell & Jupp, 2000, (TRACE),
Koutchmy et al. ...
Dissipation of magnetic energy & small scales
                                                          DC

     2. Heatin...
Chromosphere: spicules and p-modes

                                                        Swedish 1-m Solar Telescope
  ...
Ejection +30 km/s




     The Moving Sun
The prominences: general properties
Big light draperies suspended above the
surface suspendues:                           ...
The chromosphere: general structure
Observations in H :
     Eruption phenomena
Filaments et prominences:
     Situated in...
The promineces: quiescentes an eruptives
Two evolutionary stage:

 Quiescentes prominence:
     Stable structure during da...
The prominences: eruptions

Eruptions of prominences:
    Associated to flares in AR, can
    occur far from AR.
    Assoc...
The Prominences: formation mechanism
Different configurations are possible with commn points:
    Magnetic arcade above th...
The prominences: strings of twisted fluxes

   3D MHD Model:
       Appearence of twisted strings by
       application of...
Quiet atmosphere: Transition region

Thin layer: thickness < 100km
Extreme T gradient gradient: from 2 x104 up to 1 x106 K...
Transition region: structures

Emission in EUV ( <
120nm):
    Emission lines of strongly
    ionized atoms.
For increasin...
Transition region: structures / temperature




SOHO/SUMER, CIV

                  SOHO/SUMER, SVI

                      ...
Magnetic transition

In the high chromosphere and transition region, a transition in
the relation bewteen magnetic pressur...
Transition region: topology




          The Moving Sun
Transition region: global dynamics

"Blinkers":
    Localized intensity peaks in quiet
    Sun
    Lifetime < 10 min>
    ...
Transition region: global dynamics




             The Moving Sun
Transition region: global dynamics




             The Moving Sun
II
Solar Corona and Heliosphere




           The Moving Sun
The Corona: General Structure
New structure appears
in the coronal emissions
(X-UV)




                           The Mov...
Solar Atmopshere: the Corona

  Most long part of the Solar
  atmosphere
  Before space era, observed
  during eclipces
  ...
Couronne: structures principales

         Jets coronaux (équateur, latitudes
         intermédiaires)
         Condensati...
Corona: limb brightenings



SOHO/SUMER Si VI   SOHO/SUMER C IV

                                     SOHO/EIT Fe XI




 ...
The Solar Cycle



              The Solar activity strongly varies with
              11 years period as sunspot index
  ...
The Solar cycle




     The Moving Sun
The Solar Cycle: magnetic field and X-Ray.




   1992                1999

                                    Yohkoh Sof...
Active Regions dynamic




                                   In the corona, above intensive
                             ...
The corona: bright points

Small compact structures in the quiest
Sun and coronal holes. Environ 300 sur
toute la surface
...
The Corona: Coronal Holes

Less dense zones ( factor 4 -
10) and less hot (1 x106K) :
   No X-Ray emission – hole.
Quit re...
Coronal Loops




                  In the corona,
                  magnetic field lines
                  form loops rem...
The Coronal Loops

                  Basic elemnts of quit and
                  active Corona.
                      Clos...
The Coronal Loops: Dynamics

Strong thermal
conductivity thermique
along B lines.
Weak conductivity in
perpendicular direc...
Coronal loops dynamic




                        TRACE


       The Moving Sun
Coronal Loops




   The Moving Sun
Coronal Loops




   The Moving Sun
Boucles coronales




     The Moving Sun
Boucles coronales




     The Moving Sun
Coronal Loops




   The Moving Sun
Conclusion: quiet atmosphere
The quiet Sun forms the context where the violent transitory events may
occur.
It affects and...
Flares and CMEs




    The Moving Sun
Solar Flares: definition
Sudden and temporary heat of the certain volume of solar
atmosphere, producing plasma > 107 K and...
Solar Flares: Chronologic scenario

Many phases

Precursor:
   Small energy release
   Radio and soft X Ray


Impulsive ph...
Chronology: Pre-eruption phase.

Slow accumulation and energy storage in the twisted magnetic
filed:
    Instability trigg...
Solar Flares: classification

Reference measurment, GOES:




                              The Moving Sun
Solar Flares: morphology and et dynamics

Mechanism: magnetic reconnection
Observed emmisons come from difefernt
layers.

...
Model: Motivations



                                                           Energy release associated to solar flares...
Motivations
Traditional approchaes do not work:




 Some limitations of ‘traditional’ simulations
 MHD, Kinetics, PIC sim...
Lattice model (since 1991)




                          92

         The Moving Sun
Part I


Small Scale drivers of different properties

Different mechanisms of current dissipation


             Do they i...
Magnetic field
                                                                       Mechanism of Electric current
  Smal...
Power Law for Flares WTD
      Waiting Time Distribution (WTD) between
    flares is rather robust and easy characteristic...
Power Law for Flares WTD

   Power Laws: Indicator of long-range
     correlations    Turbulence?


   – effect (turbulent...
Intermediate Driving Scales of coronal heating

Inverse cascade by                 – effect




                          ...
Turbulent dynamo: history (1/3)
Origin of solar magnetic field by turbulent dynamo (Moffat 1978, Zeldovitch 1983)
      ef...
Turbulent dynamo: history (2/3)




                              99

             The Moving Sun
Turbulent dynamo: history(3/3)




                             100

            The Moving Sun
Introduction of      -effect in the model
  Dynamo: generation of magnetic field by plasma
turbulence. Can be important ne...
Large and intermediate scale sources
 Spatial structure of the magnetic field, taking into account the    -effect.

      ...
Dynamics: chromosphere




        The Moving Sun
Dynamics: chromosphere




        The Moving Sun
Dynamics: chromosphere

Frequent appearance and eruption
of bright double ribbon and neutral
line.




                   ...
Waves on the Sun




                     A flare trigger a Sunquake




                               SOHO/MDI


    The...
Dynamique: chromosphère

Fast magnetsonic shock
propagation (Moreton wave)
Associated to strong flares.
   V ~ 1000 km/s

...
Dynamics: Corona (Extreme UV)




      TRACE: 19,5nm, T=1,5x106K


             The Moving Sun
Dynamics: Corona (Extreme UV)




Double flare at 15 avril 2001 (sympathetic flares)
           TRACE: 17,1nm, T=1x106K

 ...
Dynamics: Corona (Extreme UV)




Flare sequence d'éruptions Octber -November 2003
         SOHO/EIT: 19,5nm, T= 1,5x106K
...
Dynamics: Corona (X and            Rays)

RHESSI: first images in X and rays
Primary source of heat during impulsive phase...
Dynamics: Corona (X and        Rays)

Thermal emisison in soft X-
Ray (<10 keV) present
along all loop.




Non-Thermal em...
Dynamics: post-eruption arcade
Progressive seperation of arcade
footpoints :
    V : ~10 km/s
   Indication of reconnectio...
Solar Flares: magnetic reconnection




All models reproducing the topology of flare energy release imply
    Very small s...
Solar Flares: magnetic reconnection
Simplest topology (Sweet 1958, Parker 1963): neutral sheet
   Typical X- configuration...
Solar Flares: magnetic reconnection

Petschek Model(1964):
   Slow shock waves production from
   reconenction site.
   Pa...
Solar Flares: unated model.




          The Moving Sun
EIT waves: definition

Bright front visible in the
EUV. It propagates in the
solar corona with the
velocity of 100 km/s fr...
EIT waves: example du 12 mai 1997

Éruption C1.3 flare with
filament eruption and
halo CME.




   SOHO/EIT
  Fe XII, 19,5...
Ondes EIT: exemple du 12 mai 1997


Différences entre images
successives
Vitesse de propagation:
     250 km/s




    SOH...
EIT waves: dimmings


   Plasma evacuation
   Magnetic lines opening               Arcade post-éruption
Association to CME...
Ondes EIT: déflection (TRACE)

                19,5 nm (FeXII) 17,1 nm (FeX) H Ly (121,6 nm)




Images




Différences


...
EIT and Moreton waves

Moreton waves associated to flares
are observed in the chromopshere
Les ondes de Moreton
Inital vel...
EIT and Moreton waves

Cospatiality is still
uncertain:
   Coincidence only near
   eruption cite. (Thompson et
   al. 200...
Trigger by wave front




Coronal shocks (Thompson, 1998)
                                                 125
           ...
Solar Influence Data analysis Center

                              Flares Catalog




               Manual              ...
SIDC Flare Catalog




o Since 01/01/2004 SIDC provide correlation between each
flare and NOAA Active Region. This allows ...
Velocity of Perturbation


                                o We compute the distance along
                 t2   t3       ...
The first consideration of global inter-flaring spatial
                     properties.
      PDF of the speed flare-to-f...
Time-distance coronal seismology ?
                                 JOINT PDF



Inter-flare distance




                ...
EIT waves: modeles

Formation of 2 wave
structures:
   Big wave with flou
   contour is EIT
   wave(250 km/s)
   Shock dri...
EIT wave front rotation




                          EC
                                                   EC
           ...
Attrill et al 2007



12th May 1997 ACW event




                                                 Reverse “S” sigmoid

  ...
CME flux rope eruption




                                   Evolution in two phases:
                                   ...
Schematic View of Coronal Wave


• The highest point of wavefront (point E) is
  percived by both spacecrafts.

• EF: wave...
Cup of Coffee Analogy




High cup borders close from our view the correspondent bottom
                              part...
CMEs 3D Studies
                      Simultanious View


STEREO - A       STEREO - B




                 The Moving Sun
Improving Resolution
                       exist at Micro-Scales




EUV Micro-Erptions                             Extra...
WHI STEREO-A DETECTIONS
           STEREO-
                       30 March Event




of dimming intensity
                ...
WHI STEREO-B DETECTIONS (3/4)
    STEREO-
           Event March 30


                               Violent events
      ...
WHI STEREO-B DETECTIONS
               STEREO-
                                           Event March 25


               ...
Flares




TRACE
                         Big Bear Solar Observatory

        The Moving Sun
Flares




                 TRACE


The Moving Sun
Radiation storms




                        A Flare in “suitable place” can émettre
                        in the Earth ...
Coronal Mass ejection




During Flares, big plasma clouds are
often ejected from the Sun,
producing Coronal Mass Ejection...
Coronal Mass-Ejection (CME)




                           SOHO/LASCO




          The Moving Sun
Eruptive Prominences


                                                  Mauna Loa




                      The prominenc...
Halo CME after Prominence Eruption




When CME is directed toward the
Earth we can see it as the Halo
CME. First o all we...
Halo CME




                 SOHO/LASCO




The Moving Sun
Halo CME




                 SOHO/LASCO




The Moving Sun
cH   B2   0

                                      Solar Activity: CME

              Bright structure of plasma ball that...
CMEs: structure in 3 parts
3 composantes imbriquées :
   Bright front supposing expanding magnetic loop.
   Dark Cavity
  ...
ICMEs: Sursauts radio



    Type II burst (hectometric and kilometric band,
    20 - 1000 kHz)
       Measured only out o...
CMEs: structure

Some structures(jets) can be destructed by CME
passage but CMEE keeps its form during whoel
propagation.
...
ICMEs: magnetic clouds

Ejected Magnetic cloud
transports magnetci field.
Caracterised by:
   Important and progressive
  ...
ICME in CIR: corotation interaction regions

Density, T and B increase
Crusial 180° inversion of the
direction of the azim...
Heliosphere: CIR

Quand un courant de vent rapide suit
un secteur de vent lent, le vent rapide
repousse le vent lent et in...
Heliosphere: propagation of ICMEs and CIR

Simulation of
subsequent CMEs of
Ocober 2003).
Animation of
interplanitary magn...
CMEs: propagation




     The Moving Sun
CMEs: structure

Different morphologies:
    Interaction with solar wind
    and B.
Internal complex
structure:
    Multip...
CMEs: 18 October - 7 november 2003

Periode of very strong activity in 2 active regions   (EIT: Fe XII, 19,5 nm)




     ...
CMEs: 18 october - 7 november 2003




              The Moving Sun
CMEs: sources and precursors

Eruptive filament
evolution on solar disk
EIT (FeXII)
6 h later CME
detected.




          ...
CMEs: dimmings EIT

Dark regions after EIT waves
triggered by flares: :
   Eruption mode: opening of magnetic
   field lin...
CMEs: EIT dimmings

   Flows, 30 km/s (SOHO/CDS, Harra & Sterling 2001)
   Disispation during expansion.
   NEMO




SOHO/...
Waves on the Sun




In these images obtained by
substraction of the previous
one, one can better follow the
gigantesque s...
CMEs: velocitis and acceleration

2 classes of CMEs (Sheeley et al. 1999):
   Gradual CME :
      Formed by the prominence...
The Moving Sun
The Moving Sun
The Moving Sun
The Moving Sun
The Moving Sun
The Moving Sun
CMEs: latitude distribution
Minimum (1996)                        Maximum (1999)




                     The Moving Sun
CMEs HALO

The most importnat class for solar
tererstrial relation.
    Shocks source, SEP and geomagnetic
    perturbatio...
CMEs halo




 The Moving Sun
CMEs halo
Progressive differences




                           The Moving Sun
CMEs: modeles
Basic elements to reproduce: the observations imply the shearing/torsion
of magnetic field applyed along the...
CMEs: sources and precursors

Ejected filament is often twisted – helicity
   Energy storage in teh helicity.
   Unrolling...
CMEs: precursors and helicity




         LASCO C2, 2/6/1998, 13h31



            The Moving Sun
CMEs: precursors and helicity




           The Moving Sun
CMEs: modeles
5 categories of modeles:
1. Thermal deflagration
2. Dynamo
3. Mass loading
4. Rupture of connections ("tethe...
CMEs: modèles
Lin et al.
2004




                The Moving Sun
LASCO as the Comet hunter


                              With the help of LASCO a
                              thousand ...
Solar Wind: the first indiexes

First observations suggested the expanding
medium in the solar system 19th century:
   Car...
Solar wind: Velocity Profile

Asymptotique velocity at long
distance as the function of teh
temperatur ein teh low corona ...
Solar wind: acceleration
Heating and acceleration of teh
fast solar wind by MHD waves
by the mechanism of the ion-
cyclotr...
Solar wind: the source localization

SOHO/SUMER: observation –
doppler shift in NeVIII (77,0 nm,
T= 650 000K) (cf. Hassler...
189
The Moving Sun
190
The Moving Sun
SECCHI suite




                    191
   The Moving Sun
HI-1 CME




                  192
 The Moving Sun
HI-1 CME-Venus




                     193
    The Moving Sun
ICME at the Earth




                     When CME achieve the
                     Earth, it perturbs the
              ...
Polar Aurora

                   The CME impact on the Earth
                   trigger very often a geomagnetic
         ...
Aurores

Au passage d'un CME, injection renforcée d'énergie et de particules
dans la magnétoqueue.




                   ...
Impacts sur l’environnement terrestre




               The Moving Sun
END
        That was only a flyover of the Sun,
     an exciting star in direct contact with our
                    envir...
Solar Space projects in near future




             The Moving Sun
SDO: AIA

Central satellite of NASa program
"Living with a Star"
Launch: 2008-9
5 - 10 ans
Orbite: geosynchronous
     (TB...
SDO: AIA

3 instruments
  HMI: helioseismology, vector magnetograph
  EVE: spectro-photometre UV-EUV
  AIA: telescope EUV ...
Solar Orbiter / EUI: Extreme UV Imager
Mission:
   Launch: 2013
   5 - 7 ans
Orbit:
   Distance to Sun: 0,21 AU (32 millio...
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Astrophysics and Solar Physics

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AACIMP 2009 Summer School lecture by Elena Podladchikova.

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Astrophysics and Solar Physics

  1. 1. Royal Observatory of Belgium Our Dynamic Star Elena Podladchikova The Moving Sun
  2. 2. The Sun Main source of heat and light. Stability of the Sun – stable Earth conditions at geological scales. Only for human eye Sun seems to be stable. In reality solar weather is strongly variable. The Moving Sun
  3. 3. Why study the Sun? The Star presenting all the details of its surface. Physical laboratory with the conditions impossible to reproduce on the Earth. Influence on the terrestrial environment. Activity of this Star produced the life on its planet - unique case. The Moving Sun
  4. 4. SOHO/EIT SOHO (Solar and Heliospheric Observatory) — spacecraft to observe the Sun. Joint ESA-NASa mission. launch – 2 december 1995 start ) May 1996 Has 12 instruments onboard. Information about solar atmopshere, solar inetrior, solar wind and solar corona activity. One of the main instruments: EIT (Extreme ultraviolet Imaging Telescope) The Moving Sun
  5. 5. SOHO and STEREO Continous Extreme Ultraviolet Imaging of the Sun ORBITS STEREO has 2 spacecrafts SOHO is in the L1 Lagrange point The "Ahead" spacecraft is flying completely in the Solar-Terrestrial System away from Earth, and becomes a satellite of the Sun. and goes around the Sun while the "Behind" spacecraft is flying in the simultaneously with the Earth. opposite direction. The Moving Sun
  6. 6. SOHO and STEREO SOHO and STEREO monitor the solar corona in 4 central wavelengths corresponding to the different temperatures PARAMETERS SOHO 171 A 195 A STEREO Temporal Cadence Temporal Cadence 171 A: 1/h - 4/day 171 A: ~2.5 min 195 A: 15 -12 min 195 A: 10 min 284 A: 1/h - 4/day 284 A: 10 min 304 A: 1/h - 4/day 284 A 304 A 304 A: 10 min Spatial Resolution Spatial Resolution 1024 x 1024 pxls 2048 x 2048 pxls The Moving Sun
  7. 7. Outline Introduction Presentation of 3 aspects: The Sun and “quiet” atmosphere (permanent regime) Manifestations of the Solar Activity. Solar influence on the Earth. The Moving Sun
  8. 8. The Sun: basic characteristics Ordinary yellow dwarf , type G2 Far from the center in the galactic disk of the Milky Way. Phase of principal sequence: Since 4,5 milliards years For 5,5 milliards years Stable structure, but luminosity evolution ~ 10 % on many milliards years (A-B). Some Stellar Properties: Absolute magnitude: +4,5 Effective Temperature: 5780 K Masse: 2 x 1030 kg Rayon: 7 x 108 m Gravitational acceleration at the surface: 273,8 m/s2 Critical Ejection velocity: 617,7 km/s Rotation: 25.38 d The Moving Sun
  9. 9. The Multiple solar roles Gravitational attraction of the planets ( orbits, tides ) Environment determined by solar electromagnetic radiation absorption (from gamma ray to infrared) Influence by corpuscular emission (electrons, protons, -particles, etc.): Solar Wind: Mass lost 2 millions tonnes per second Solar neutrinos : No influence, but direct information about nuclear reactions in the core. The Moving Sun
  10. 10. The Sun: structure The Moving Sun
  11. 11. I From the core to transition region The Moving Sun
  12. 12. Quiet Atmosphere: introduction Quiet Sun: Structures with weak time dependences (weak magnetic fileds) Large solar structures are little variable. Active Sun: Variable phenomena. Brutal local deviations and transitory variations with respect to the quiet Sun. The Moving Sun
  13. 13. The different Faces of the quiet Sun. 4 principal layers: Photosphere Chromosphere Transition region Corona (heliosphere) Complete changing of physical conditions trough the layers: The Sun does not appear the same in the different wavelengths. The Moving Sun
  14. 14. Quiet photosphere: the granulation The solar surface is covered by a pattern constituted by bright granules separated by the dark network. Imprint of subphotospheric convective movements. Size: 500 - 1500km (1") Contrast: 10% ( T=150 K) The Moving Sun
  15. 15. Quiet photosphere: the granulation Developed turbulence: At large scales: regime of inetrtial convection (advection of heat dominates) At small scales: regime of inertial conduction (heat diffusion) Velocity field Granulas center: ascending Interagranulas: descending Velocities: 1-2 km/s Lifetime: <4 min> Verticale structure of convective cells The Moving Sun
  16. 16. Photosphère calme: Points brillants et tubes de flux Photopspheric Bright Points: In the intergranulas B concentration in the descending flows Flux tubes: Diameter: <100km Magnetic Induction: 1000 à 1500 G Canals transporting convective energy in the form of magneto-acoustic shocks (Choudhuri, 1993) Exponential growth of the amplitude (Kalkofen 1997) The Moving Sun
  17. 17. Magnetic network evolution Magnetic fields are in the continuous evolution. Their interaction produce coronal heating. Ephemeral Regions Small regions, no specific magnetic orientation. Life time <4.4h> The Moving Sun
  18. 18. Photosphere: supergranulation Organisation of the granulation in the larger pattern Mesogranulation: Scales: 5000-10000 Km Trace of turbulent dynamo at small scales (Cattaneo et al. 2001). Supergranulation (Leighton 1962): Scales: 20 000 – 30 000 Km Lifetime: <12 h> The Moving Sun
  19. 19. Photosphere: faculaes More hot regions The Moving Sun
  20. 20. The sunspots: proprties Photospheric dark regions. Small spots without structure (pores): Diameter <2500km For D >2500km, 2 zones: Umbra : Diameter =10 - 15000km Intensity = 5 - 30% IPhotosphere Penumbra: D: 50000km Intensity = 50 à 70 % IPhotosphere The Moving Sun
  21. 21. The sunspots: penumbra Vertical field in the umbra Horizontal field in the penumbra Radial Filaments structure Continuous flow from the center to the borders: Evershed flow Velocity: 1 - 2 km/s The Moving Sun
  22. 22. Sunspot Dynamics (Dutch Open Telescope) The Moving Sun
  23. 23. Sunspots: Magnetic field Pass point of intensive magnetic field trough the thin photospheric layer. Global dipolar structure: N-S Polarity oriented E-W Inclination with respect to equator: 12° Group traversed by a neutral line Complex topology Intensity: Umbra: 3000 G Penombra: 1000 G The Moving Sun
  24. 24. The sunspots: properties Lifetime: hours-months Umbra Temperature: 4000K Quiet photosphere (5800K). Groupes ellongated in the E-W direction 5 ° - 40° of latitude The Moving Sun
  25. 25. Sunspot Dynamics (SOHO/MDI) Intensity The Moving Sun
  26. 26. Magnetic field and sunspots. The sunspots are associated to intensive magnetic field (black and white spots on the magnetogram at right), that change continuously. The Moving Sun
  27. 27. The sunspots: Field hierarchy Young groupes: Compact field Old groupes: Dispersive flux Permanent fields: Neutre diagonal line Weak global field (10-4 T) that inversed with the Hale cycle (22 ans) The Moving Sun
  28. 28. Sunspots and activity cycle The number of sunspots varies with teh cycle of ~ 11 ans: Cycle amplitude (maxima): 48 in 1817 and 200 in 1958 ~90 years modulation Archive Bruxelles): 30 cycles 3 centuries Daily index since 1850 The Moving Sun
  29. 29. Sunspots and cycle: distribution in latitude (« Batterfly ») Toward equator during the cycle: First spots: at 30° latitude At maximum: at 15° Last cycle spots: at < 5° from lthe equator (at 0°) Spots of 2 cycles coexistent during the activity minimum. The Moving Sun
  30. 30. Solar Dynamo: - effect Ionized solar plasma: Plasma movements = large scale currents. Magnetic field lines are frozen in the plasma under the surface: Poloidal (dipolar) magnetic field is elongated and coiled by the differential rotation -> amplification. Complete process - 8 m. Toroidal field production in the opposite direction The Moving Sun
  31. 31. Solar Dynamo: -effect Magnetic lines torsion by the solar rotation, via the Coriolis force. Convection helicity generates a electromotive force proportional to this helicity and to toroidal magnetic field. The energy of the dynamo comes from kinetic energy of rotation and fluid movement at small scales in the convective zone. The Moving Sun
  32. 32. Ascending and torsion of magnetic loops B puts pressure on the background medium: ~ B2 Evacuation of plasma in the flux tube up to the equilibrium of the pressure with background unmagnetized plasma: The loop, less dense that ambient plasma go up toward the surface: Loop formation in During the rising - rotation by Coriolis: DIpole inclinnation (opposite sens) B helicity During the cycle the emergent loops ar ereformed by the reconnection and fragmentation with global dipolar field: Reconstitution of the initial poloidal field The Moving Sun
  33. 33. The dynamo in movement The Moving Sun
  34. 34. Looking at far side of the Sun Helio sesimology informs us about the far side of the Sun. One can see here how the sunspot group (with intesive magnetic field) can be followed during many solar rottaion. (Here the Sun is fixed and the observer is moving.) SOHO/MDI The Moving Sun
  35. 35. Waves on the Sun: helioseismology Thousand of acoustic waves parcourent continuously the solar surface. One can hear them accelerated 42000 times. Analysing these waves one can investigate the Solar Interior and deduce for example the sound speed. SOHO/MDI The Moving Sun
  36. 36. Looking IN the Sun The helioseismology informs us about Solar interior as well as about changing structure of solar rotation. One can find the rotation bands more fast (red) and more slow (green and bleu) The Moving Sun
  37. 37. Exterior Atmosphere Chromosphere and Transition Region The Moving Sun
  38. 38. The chromosphere: general structure Much more dynamic medium, that the photosphere Important spatio/temporal variations of the emission. Chromospheric network: Scales corresponds to supergranulation: 20 – 30 000km. Enhanced emission on the granula borders, concentration of strong magnetic field (tubes de flux). Brightenings around AR, correspondance with faculaes. CaII K filtergram, Kitt Peak Obs., USA TRACE, Ly The Moving Sun
  39. 39. Fine structure fine: the spicules Surface covered by the vertical spouts (~100 000 on teh Sun), the spicules: Temperature: 4500K Height: 5 000 – 20 000 km At the limb: bright (spicules) Section: 500 km Disk center: dark (mottles) Ejection speed: 20 km/s Inter-spiculaire space hot (106K) and not dense. Lifetime: 5 à 10 min Mass flux: 100 x the necessary flux to maintain the solat wind. Essential role in the balance of mass flux in the solar wind. The Moving Sun
  40. 40. The chromosphere: heating source The turbulent photopsheric convection provides energy to heat upper layers. It produces propagating acoustic waves: Acoustic waves: In the unmagnetized interior of supergranulas. Excitation by the random vertical movement. Resonance chromopsheric cavity is on the level of cut-off frequency of p- modesaAt 5 mHz (P=3min). MHD modes: Slow and fast Magnetoacoustic, Alfven. Excitation by the footpoints displacement. Transformation in shock waves. Other sources: Macroscopic flows (Spicules) Current dissipation (reconnection magnétique locale) Reviews: Narain & Ulmschneider (1990), Ulmschneider et al. (1991) The Moving Sun
  41. 41. Atmopsheric Model Coronal heating problem: why is the corona so hot? Vertical profile of temperature and density in the Solar atmosphere The Moving Sun
  42. 42. Dissipation of magnetic energy & small scales 2 traditional approchaes AC/DC 1. Heating by MHD waves Dissipation of Alfvén waves (Alfvén 1947) problems: how are they excited? how are they dissipated? how are formed the small dissipative scales? Resonance absorption (Ionson 1978) problems: waves with small periods needed (5 – 300 sec) [Davila, 1987] Phase mixing (Heyvaerts & Priest 1983) Ion cyclotron waves (McKenzie et al. 1995) Turbulent cascade to small scales problems: (next slide) 42 The Moving Sun
  43. 43. Turbulent cascade to small scales Natural mechanism to form small scales The couplings between waves and turbulence are universal mechanism in fluid forming small scale fluctuations: Developed turbulence. Energy cascade from large scales to small ones. (Kolmogorov 1941, Frisch 1995): E(k) ~k - Conducting fluid. + <B> But nT and B2 also dissipate after cascade toward small scales (Iroshnikov et R. Kraichnan), E(k) ~k -3/2 43 The Moving Sun
  44. 44. Turbulent cascade to small scales Problems : 1. Energy flux of waves transformed to particle energy: - Only small part of W diss ~ ( i/ driver) -1 x W total Total Energy dissipates 2. Slow processes (open regions). Distance Lmin ~ Rsol - Spectra forms at very large distance from the Sun 3. Time to form turbulent spectrum: T~ 10 Lmin / Cs - is too long 4. Sources are not only in large scales 44 The Moving Sun
  45. 45. Experimental Evidence of small scale sources Krucker & Benz , 1998 (SOHO), Parnell & Jupp, 2000, (TRACE), Koutchmy et al. , 1997(X-ray) etc… – experimental confirmation of important role of nanoevents in coronal heating. Aschwanden et al. (2000) - quasi-homogeneous spatial distribution of nano-flares.(SOHO, TRACE) Shriver et al. 1998, - (quasi-homogeneous spatial distribution of small scale dipoles) (SOHO) Abramenko et al. 1999 – inverse helicity cascade (Big Bear) Berghmans et al 1999, Benz et al, intracell nanoflares. Krasnoselskikh et al, 2002 - The characteristic scale of magnetic loops which provide energy deposition into the corona is of the same order as the dissipation scale. Observations of magnetic loops of different large scales in EUV 45 The Moving Sun
  46. 46. Dissipation of magnetic energy & small scales DC 2. Heating by dissipation of DC currents dissipation • Anomalous resistivity (Handbook of Plasma Physics, edited by M.N. Rozenbluth and R.Z. Sagdeev, Priest et al, Voitneko et al. ) • Reconnection (Giovanelli,1946) Comment: There is no strong difference between AC and DC mechanisms: They both describe the coronal response to perturbation created by sub-photospheric convection (Heyvaerts,1990). The distinction essentially depends on time scales tA >> tphotosph AC tphotosph>> tA DC Nowadays DC mechanisms are more compatible with coronal observations. 46 The Moving Sun
  47. 47. Chromosphere: spicules and p-modes Swedish 1-m Solar Telescope with adaptative optics. Spatial resolution ~100km (0,15") New result: The spicules are forme at the same point and in phase with oscillation of photopsheric p – modes, with the coherent period of 5 min. (De Pontieu et al. 2004, Nature, Zhugzda et al. 1987, JETP) The Moving Sun
  48. 48. Ejection +30 km/s The Moving Sun
  49. 49. The prominences: general properties Big light draperies suspended above the surface suspendues: , BBSO Cold and dense masses of gaz. Mix Structures: Coronal and chromospheric. Properties: Temperature: 10000 K Density: 1010 à 1011 cm-3 (500 x coronal density) Height: 20 – 100 000 km Width: 10 000 km Lenght: up to 1 Rs TRACE, FeX, 17,1 nm The Moving Sun
  50. 50. The chromosphere: general structure Observations in H : Eruption phenomena Filaments et prominences: Situated in the corona Prominences: off-limb. Filaments: on disk Coronographe, Obs. Pic-Du-Midi filtergram, USET, ROB, Bruxelles Localisation: Above neutral lines of the photopsric B: Often E-W orientation. The basis of coronal jets. The Moving Sun
  51. 51. The promineces: quiescentes an eruptives Two evolutionary stage: Quiescentes prominence: Stable structure during days. Eruptive promineces: Fast ejection ~1 h. SOHO/EIT, HeII, 30,4 nm The Moving Sun
  52. 52. The prominences: eruptions Eruptions of prominences: Associated to flares in AR, can occur far from AR. Association to CME. Vielocity: up to 1000 km/s Magnetic energy liberation during the eruption. The Moving Sun
  53. 53. The Prominences: formation mechanism Different configurations are possible with commn points: Magnetic arcade above the neutral line. Horozontal flux trapped in the arcade The Moving Sun
  54. 54. The prominences: strings of twisted fluxes 3D MHD Model: Appearence of twisted strings by application of convection velocity field at the photospheric level. (Amari, T. et al., ApJ518, 1999; Aly, J.J. & Amari, T. AAp207, 1988, ) The Moving Sun
  55. 55. Quiet atmosphere: Transition region Thin layer: thickness < 100km Extreme T gradient gradient: from 2 x104 up to 1 x106 K Abrupt transition betwen chromopshre and corona. T profile and typical emmission lines in TR. The Moving Sun
  56. 56. Transition region: structures Emission in EUV ( < 120nm): Emission lines of strongly ionized atoms. For increasing T transition transition from chromsopehric structures: Cgromospheric newtork, spicules, prominences To coronal structures: Coronal holes, loops. SOHO/EIT, HeII, 30,4 nm T= 8 x105 K The Moving Sun
  57. 57. Transition region: structures / temperature SOHO/SUMER, CIV SOHO/SUMER, SVI SOHO/EIT, HeII, 30,4 nm, T= 8 x105 K The Moving Sun
  58. 58. Magnetic transition In the high chromosphere and transition region, a transition in the relation bewteen magnetic pressure in the flux tubesand teh kinetic pressure of the gaz. Coefficient du plasma: p B2 2 0 Photosphere and chromosphere: >>1 Filed confined in the thin flux tubes in the intragranulas space. Filed frozen in plasma: turbulent convection disturb the filed. Transition region and Corona: <<1 Magnetic filed expands for whole avaliable volume. Plasma is entrained by its movements. NB: In the solar atmopshere not a lot of regions has 1 The Moving Sun
  59. 59. Transition region: topology The Moving Sun
  60. 60. Transition region: global dynamics "Blinkers": Localized intensity peaks in quiet Sun Lifetime < 10 min> Surface: 100 Mm2 High density Small velocity. Injection of heated chromopsheric plasma (« evaporation »). The Moving Sun
  61. 61. Transition region: global dynamics The Moving Sun
  62. 62. Transition region: global dynamics The Moving Sun
  63. 63. II Solar Corona and Heliosphere The Moving Sun
  64. 64. The Corona: General Structure New structure appears in the coronal emissions (X-UV) The Moving Sun
  65. 65. Solar Atmopshere: the Corona Most long part of the Solar atmosphere Before space era, observed during eclipces Continous expansion avec V ~400km/s: solar wind. Extension on many AU: the heliosphere with all solar planets inside. Very inhomogeneous layer structured by magnetic field ( <<1) The Moving Sun
  66. 66. Couronne: structures principales Jets coronaux (équateur, latitudes intermédiaires) Condensations coronales (base des jets, contenant parfois une cavité) Trous coronaux sombres (pôles) Plumes polaires (pôles) Protubérances (chromosphère, H ) Grands écarts de densité: jets 10 x trous The Moving Sun
  67. 67. Corona: limb brightenings SOHO/SUMER Si VI SOHO/SUMER C IV SOHO/EIT Fe XI The Moving Sun
  68. 68. The Solar Cycle The Solar activity strongly varies with 11 years period as sunspot index indicates already ~200 years. The changes are more visible in the corona. The Moving Sun
  69. 69. The Solar cycle The Moving Sun
  70. 70. The Solar Cycle: magnetic field and X-Ray. 1992 1999 Yohkoh Soft X-ray Kitt Peak magnetograms The Moving Sun
  71. 71. Active Regions dynamic In the corona, above intensive magnetic field one can see the Active Regions in the permanent evolution. From times to times they produce magnetic field instabilities that lead to solar flares or eruptions. SOHO/EIT The Moving Sun
  72. 72. The corona: bright points Small compact structures in the quiest Sun and coronal holes. Environ 300 sur toute la surface Ephemeral AR(small loops) Lifetime: 2h – 2 days. High density Modele: magnetic submerging dipole. The Moving Sun
  73. 73. The Corona: Coronal Holes Less dense zones ( factor 4 - 10) and less hot (1 x106K) : No X-Ray emission – hole. Quit region of quiet photopshere. Open B. Plasma escapes. The Moving Sun
  74. 74. Coronal Loops In the corona, magnetic field lines form loops remplished by plasma, as one can see on EIT images. These loops are in permanent movement. The Moving Sun
  75. 75. The Coronal Loops Basic elemnts of quit and active Corona. Closed B. Keeping of coronal plasma. The Moving Sun
  76. 76. The Coronal Loops: Dynamics Strong thermal conductivity thermique along B lines. Weak conductivity in perpendicular direction. Isolated loops with individual evolution. PLAsma transport is possible only along B: Macroscopic flows along the loops (v ~ 100 km/s) = intensive currents. The Moving Sun
  77. 77. Coronal loops dynamic TRACE The Moving Sun
  78. 78. Coronal Loops The Moving Sun
  79. 79. Coronal Loops The Moving Sun
  80. 80. Boucles coronales The Moving Sun
  81. 81. Boucles coronales The Moving Sun
  82. 82. Coronal Loops The Moving Sun
  83. 83. Conclusion: quiet atmosphere The quiet Sun forms the context where the violent transitory events may occur. It affects and modulates the properties of active penomena (Corona and solar wind). It is formed by similar phenomena by at the small scales, weak energies. Multiple of those micro phenomena create « permannet regime » from teh global point of view. The Moving Sun
  84. 84. Flares and CMEs The Moving Sun
  85. 85. Solar Flares: definition Sudden and temporary heat of the certain volume of solar atmosphere, producing plasma > 107 K and associated to fast reconfiguration of magnetic field. First observations in 19 century: White light flares – very rare phenomena. Emissions in: From gamma rays to X – extreme temperature Radio waves: indication of accelerated particles. Most energetic solar explosif phenomena in solar : Energy up to 1032- 1033 ergs in ~ 10 – 103 seconds The Sun is also a power particle accelerator: Electrons: ~100s of electrons 1 MeV: Electrons of energies ~10-100 keV - 50% of whole energy Generation of 1036 electrons/s and currents of 1017 Amps. Ions: ~ 10s of particles 1 GeV : The ions of energies >~1 MeV can transport total energy. The Moving Sun
  86. 86. Solar Flares: Chronologic scenario Many phases Precursor: Small energy release Radio and soft X Ray Impulsive phase: Explosive energy injection Many fast jumps. -rays Principal long phase: Energy release. Gradual evolution Maximum and strat of teh coronal and chromospheric (continuum,H ). The Moving Sun Dulk et al. 1985
  87. 87. Chronology: Pre-eruption phase. Slow accumulation and energy storage in the twisted magnetic filed: Instability trigger after a treshold. External Generation : Emergence of Flux Flux cancelation. Random walk of footpoinst loops and by difeferntial rotation. The Moving Sun
  88. 88. Solar Flares: classification Reference measurment, GOES: The Moving Sun
  89. 89. Solar Flares: morphology and et dynamics Mechanism: magnetic reconnection Observed emmisons come from difefernt layers. 16/8/2002, USET, ORB The Moving Sun
  90. 90. Model: Motivations Energy release associated to solar flares. Power laws, flares, microflares. Power index < 2 for Parker hypothesis. System with large fluctuations (high probability)! No thermodynamic equilibrium. Crosby, Aschwanden & Dennis 1993 flares similarity at different scales and energy? what is the respective role of flares of different scales and their interaction in the heating? 90 The Moving Sun
  91. 91. Motivations Traditional approchaes do not work: Some limitations of ‘traditional’ simulations MHD, Kinetics, PIC simulations may reproduce limited spatio- temporal scales For example, ideal MHD does not describe correctly such dissipative effects as magnetic reconnection or current sheet instabilities. But coronal heating is a complex problem, with a lot of different temporal and spatial scales 91 The Moving Sun
  92. 92. Lattice model (since 1991) 92 The Moving Sun
  93. 93. Part I Small Scale drivers of different properties Different mechanisms of current dissipation Do they influence 1. Large scale observable magnetic field & 2. Global Dissipated Energy? 93 The Moving Sun
  94. 94. Magnetic field Mechanism of Electric current Small-scale sources form magnetic structures: dissipations influence PDF of energy : random source sub-diffusive intermittent source Anomalous Resistivity-Gaussian chaotic source (poor navier-stocks) super-diffusive source Reconnection dissipation – power law deviations Main conclusions. Small-Scale dissipation mechanisms influence electric currents total dissipated Enregy. 94 B-Source influences large scale magnetic field structures. The Moving Sun
  95. 95. Power Law for Flares WTD Waiting Time Distribution (WTD) between flares is rather robust and easy characteristic to compare models and experiment Problems Experimental WTD are in power laws. Waiting Time Distribution for large set of flares (e. g. Crosby 1993,1996; Weathland 2000) WTD from models are different. Nowadays all models including all known SOC, Shell and Lattice models (including all our previous studies ) shows Poissonian or exponential laws (e.g. Carbone 2000). 95 The Moving Sun
  96. 96. Power Law for Flares WTD Power Laws: Indicator of long-range correlations Turbulence? – effect (turbulent dynamo) explains the origin of solar magnetic field. -effect generates structures of larger scales from the small ones. Thus – effect can naturally provide us the “intermediate” and the large scales magnetic structures as magnetic drivers (to avoid direct cascade problems). 96 The Moving Sun
  97. 97. Intermediate Driving Scales of coronal heating Inverse cascade by – effect 97 The Moving Sun
  98. 98. Turbulent dynamo: history (1/3) Origin of solar magnetic field by turbulent dynamo (Moffat 1978, Zeldovitch 1983) effect Parker 1966, Steenbeck et al 1966 The -effect belongs to cinematic dynamos, where the velocity V is imposed. It is therefore a linear problem, whose goal is to show the large scale growth of an initial “seed” of magnetic field. 98 The Moving Sun
  99. 99. Turbulent dynamo: history (2/3) 99 The Moving Sun
  100. 100. Turbulent dynamo: history(3/3) 100 The Moving Sun
  101. 101. Introduction of -effect in the model Dynamo: generation of magnetic field by plasma turbulence. Can be important near the surface. internal source of magnetic field. Include alpha-effect in the induction equation: 101 The Moving Sun
  102. 102. Large and intermediate scale sources Spatial structure of the magnetic field, taking into account the -effect. Size ~0.3 convection cell t= 100 t =700 Source is random (inital image is white noise). Currents are dissipated by reconnection, low instability thresholds. In this run dissipation stabilizes the development of larger structures 102 Stationary state The Moving Sun
  103. 103. Dynamics: chromosphere The Moving Sun
  104. 104. Dynamics: chromosphere The Moving Sun
  105. 105. Dynamics: chromosphere Frequent appearance and eruption of bright double ribbon and neutral line. The Moving Sun
  106. 106. Waves on the Sun A flare trigger a Sunquake SOHO/MDI The Moving Sun
  107. 107. Dynamique: chromosphère Fast magnetsonic shock propagation (Moreton wave) Associated to strong flares. V ~ 1000 km/s The Moving Sun
  108. 108. Dynamics: Corona (Extreme UV) TRACE: 19,5nm, T=1,5x106K The Moving Sun
  109. 109. Dynamics: Corona (Extreme UV) Double flare at 15 avril 2001 (sympathetic flares) TRACE: 17,1nm, T=1x106K The Moving Sun
  110. 110. Dynamics: Corona (Extreme UV) Flare sequence d'éruptions Octber -November 2003 SOHO/EIT: 19,5nm, T= 1,5x106K The Moving Sun
  111. 111. Dynamics: Corona (X and Rays) RHESSI: first images in X and rays Primary source of heat during impulsive phase. The Moving Sun
  112. 112. Dynamics: Corona (X and Rays) Thermal emisison in soft X- Ray (<10 keV) present along all loop. Non-Thermal emisison (20 - 50 keV) concentrated in 3 regions : Footpoints Top Measurment of time lag bewteen reconnection source and X-Ray source. The Moving Sun
  113. 113. Dynamics: post-eruption arcade Progressive seperation of arcade footpoints : V : ~10 km/s Indication of reconnection propagating more and more high from the neutral line. After hs – reformation of filament into arcade. The Moving Sun
  114. 114. Solar Flares: magnetic reconnection All models reproducing the topology of flare energy release imply Very small scale of disispation Strong increase of local resisitivity The Moving Sun
  115. 115. Solar Flares: magnetic reconnection Simplest topology (Sweet 1958, Parker 1963): neutral sheet Typical X- configuration topology : Elongated: combined effect of Archimede force and solr wind. 2D analytical Model. Strong but unsufficient dissipation. Generation of double plasma flux with Alfven velocity. The Moving Sun
  116. 116. Solar Flares: magnetic reconnection Petschek Model(1964): Slow shock waves production from reconenction site. Particle acecleration. Energy converted into heat and acceleration half by half. Recent Models : + Turbulence Inclusion de la turbulence + 3D Topologies(Brown & Priest 2001) References: Reconenction and shocks models: Kopp & Pneumann 1976, Parker 1979, Priest & Forbes 1986, Priest & Lee 1990. Magnetic energy conversion in thermaland kinetic energy: Syrovatskii 1966, Somov 1994 The Moving Sun
  117. 117. Solar Flares: unated model. The Moving Sun
  118. 118. EIT waves: definition Bright front visible in the EUV. It propagates in the solar corona with the velocity of 100 km/s from ARs after flare: Discovered in 1997 by SOHO/EIT Can travel trough the whole hemisphere during 1h. (SOHO/EIT, 12 mai 1997) The Moving Sun
  119. 119. EIT waves: example du 12 mai 1997 Éruption C1.3 flare with filament eruption and halo CME. SOHO/EIT Fe XII, 19,5 nm T ~1.5 MK The Moving Sun
  120. 120. Ondes EIT: exemple du 12 mai 1997 Différences entre images successives Vitesse de propagation: 250 km/s SOHO/EIT Bande Fe XII, 19,5 nm T ~1.5 MK The Moving Sun
  121. 121. EIT waves: dimmings Plasma evacuation Magnetic lines opening Arcade post-éruption Association to CME. Double dimmings (tranient coronal holes) The Moving Sun
  122. 122. Ondes EIT: déflection (TRACE) 19,5 nm (FeXII) 17,1 nm (FeX) H Ly (121,6 nm) Images Différences The Moving Sun
  123. 123. EIT and Moreton waves Moreton waves associated to flares are observed in the chromopshere Les ondes de Moreton Inital velocities: 750 - 1300 km/s >> vc dans la chromosphère. No possible chromospheric origine Decceléeration Propagation up to 5 x 105km from eruptive site. Images par différences successives en Ha Observatoire solaire de Kanzelhöhe (Pohjolainen et al. 2001) The Moving Sun
  124. 124. EIT and Moreton waves Cospatiality is still uncertain: Coincidence only near eruption cite. (Thompson et al. 2000). No correspondence (Eto et al. 2002). The Moving Sun
  125. 125. Trigger by wave front Coronal shocks (Thompson, 1998) 125 Th M vin S n e o g u
  126. 126. Solar Influence Data analysis Center Flares Catalog Manual NOAA SEC/NOAA Active Region for each flare Flare list, SXI H Flare EIT Flare Other positions positions o Since 01/01/2004 unique spatial information provided by Soft X-ray Imager of GOES satellite. Firstly 84 % of all observed flares are listed with their coordinates. 11% comes from other sources. 126 The Moving Sun
  127. 127. SIDC Flare Catalog o Since 01/01/2004 SIDC provide correlation between each flare and NOAA Active Region. This allows statistically valuable study of time-distance correlation between distant flares. o 01/01/2004 – 01/09/2005: 3447 flares(B-X classes), 95 % with coordinates 127 The Moving Sun
  128. 128. Velocity of Perturbation o We compute the distance along t2 t3 the Sun's surface between all pairs of flares separated in time shorter D1 t1 than tmax=1h,2h, … 20h, assuming that flares separated in t1 D2 time larger than tmax, are uncorrelated. o We introduce the velocity of the propagating perturbation as follows: • This quantity would be meaningful only for flares which are physically connected, if any. 128 The Moving Sun
  129. 129. The first consideration of global inter-flaring spatial properties. PDF of the speed flare-to-flare intercommunication signal PDF Velocity [km/s] 129 The Moving Sun
  130. 130. Time-distance coronal seismology ? JOINT PDF Inter-flare distance Inter-flare time 130 4.817 flares measured with their time and position - complete statistical ensemble The Moving Sun
  131. 131. EIT waves: modeles Formation of 2 wave structures: Big wave with flou contour is EIT wave(250 km/s) Shock driven by the effect of « piston » has velocity 770 km/s Moreton wave vEIT ~ 0.34vfast The Moving Sun
  132. 132. EIT wave front rotation EC EC front front dimmings dimmings Podladchkova and Berghmans 2005 The Moving Sun
  133. 133. Attrill et al 2007 12th May 1997 ACW event Reverse “S” sigmoid ACW rotation Negative Helicity 7th April 1997 CW event Forward “S” Sigmoid CW rotation Positive Helicity The Moving Sun
  134. 134. CME flux rope eruption Evolution in two phases: First a twisted flux rope is created, slow and almost quasi-static; second a disruption, which is confined for a small initial helicity and global for a large initial helicity. Following the evolution of flux rope AND waves in such geometries is computationally difficult. Kink in itself tendentially slow/alfvenic Extended unfolding wave source, might conceivably explain rotation of Amari et al. 2003 wave front The Moving Sun
  135. 135. Schematic View of Coronal Wave • The highest point of wavefront (point E) is percived by both spacecrafts. • EF: wavefront height A (STEREO-A) B (STEREO-B) E D F C The Moving Sun
  136. 136. Cup of Coffee Analogy High cup borders close from our view the correspondent bottom parts The Moving Sun
  137. 137. CMEs 3D Studies Simultanious View STEREO - A STEREO - B The Moving Sun
  138. 138. Improving Resolution exist at Micro-Scales EUV Micro-Erptions Extracted Micro Dimmings Area & Intensity 103 smaller! comparing to previously known events Micro-Eruptions explain Solar Wind Formation near the Sun The Moving Sun
  139. 139. WHI STEREO-A DETECTIONS STEREO- 30 March Event of dimming intensity The Moving Sun
  140. 140. WHI STEREO-B DETECTIONS (3/4) STEREO- Event March 30 Violent events can be observed in EUV corona even during the «quiet» WHI period The Moving Sun
  141. 141. WHI STEREO-B DETECTIONS STEREO- Event March 25 Event begins at Eastren limb, globally propagates trough the eastern Hemisphere, and dissipate (or disappear) near solar center Global events can be observed in EUV corona even during « quiet» WHI period The Moving Sun
  142. 142. Flares TRACE Big Bear Solar Observatory The Moving Sun
  143. 143. Flares TRACE The Moving Sun
  144. 144. Radiation storms A Flare in “suitable place” can émettre in the Earth direction charged particles, that lead in radiation storms. Such storms are the danger for satellites and astronauts. On the animation one can see “the snow” after the flare. SOHO/EIT The Moving Sun
  145. 145. Coronal Mass ejection During Flares, big plasma clouds are often ejected from the Sun, producing Coronal Mass Ejection. SOHO/EIT The Moving Sun
  146. 146. Coronal Mass-Ejection (CME) SOHO/LASCO The Moving Sun
  147. 147. Eruptive Prominences Mauna Loa The prominences that are big clouds of plasma cooler than coronal environment can also become instable and explode. SOHO/EIT The Moving Sun
  148. 148. Halo CME after Prominence Eruption When CME is directed toward the Earth we can see it as the Halo CME. First o all we see the prominence eruption. SOHO/EIT The Moving Sun
  149. 149. Halo CME SOHO/LASCO The Moving Sun
  150. 150. Halo CME SOHO/LASCO The Moving Sun
  151. 151. cH B2 0 Solar Activity: CME Bright structure of plasma ball that propagates from low corona toward heliosphere and can interact with planet magnetopsheres. Discovered in 1970 by SKYLAB Most importnat manifestation of solar activity(together with flares) Principal source of geomagnetic storms. 2 aspects of magnetic energy release: Flares: thermal energy production(heat). CME: production of global macroscopic fluxes (kinetic energy), observed by white light. SMM, 14 avril 1980, W. Wagner Syntheses: Kahler (1987, 1992), Hundhausen (1999), Forbes (2000), Klimchuck (2001), Cargill (2001), Low (2001) The Moving Sun
  152. 152. CMEs: structure in 3 parts 3 composantes imbriquées : Bright front supposing expanding magnetic loop. Dark Cavity Interior core: fragments of dense filemanents. In situ measurments show oftehn 4th invisible composante shock wave before the bright front. The Moving Sun
  153. 153. ICMEs: Sursauts radio Type II burst (hectometric and kilometric band, 20 - 1000 kHz) Measured only out of terrestrial atmopshere The Moving Sun
  154. 154. CMEs: structure Some structures(jets) can be destructed by CME passage but CMEE keeps its form during whoel propagation. Strong magnetic conenction to the Sun. Connexion magnétique au Soleil persistante: Desattached plasmoid never clearly observed. The Moving Sun
  155. 155. ICMEs: magnetic clouds Ejected Magnetic cloud transports magnetci field. Caracterised by: Important and progressive rotation of magnetic field. Proton temperature is low with respect to ambient plasma. Dimension at 1UA: ~0,25 AU Transit to the Earth: 1 - 2 days. Produce negative Bz: Strong tererstrial magnetopsheric perturbations. Principales structures that influence Solar-Tererstrial relations. The Moving Sun
  156. 156. ICME in CIR: corotation interaction regions Density, T and B increase Crusial 180° inversion of the direction of the azimutal filed Important deviations of Bz(oscillations) Direct and invers shocks waves. The Moving Sun
  157. 157. Heliosphere: CIR Quand un courant de vent rapide suit un secteur de vent lent, le vent rapide repousse le vent lent et interagit avec lui. Compression: renforcement de la densité. Apparition d'une couche d'interface turbulente. Formation de chocs: Zone d'accélération de particules: une des sources des particules solaires énergétiques (SEP: solar energetic particles). Régions d'interaction en corotation, RIC (CIR: corotating interaction region). The Moving Sun
  158. 158. Heliosphere: propagation of ICMEs and CIR Simulation of subsequent CMEs of Ocober 2003). Animation of interplanitary magnetic field. Red: outoming (positive) Bleu: incoming (negative) Geophysical Institute, University of Alaska, 2004 TheMoving Sun
  159. 159. CMEs: propagation The Moving Sun
  160. 160. CMEs: structure Different morphologies: Interaction with solar wind and B. Internal complex structure: Multiple of loops Obsrevations in teh optically thin corona – ambiguity. The Moving Sun
  161. 161. CMEs: 18 October - 7 november 2003 Periode of very strong activity in 2 active regions (EIT: Fe XII, 19,5 nm) The Moving Sun
  162. 162. CMEs: 18 october - 7 november 2003 The Moving Sun
  163. 163. CMEs: sources and precursors Eruptive filament evolution on solar disk EIT (FeXII) 6 h later CME detected. The Moving Sun
  164. 164. CMEs: dimmings EIT Dark regions after EIT waves triggered by flares: : Eruption mode: opening of magnetic field lines. Assymetry in preexicted magnetic structre. The Moving Sun
  165. 165. CMEs: EIT dimmings Flows, 30 km/s (SOHO/CDS, Harra & Sterling 2001) Disispation during expansion. NEMO SOHO/EIT: 12/5/1997, 19,5nm Diffeernce with initial image Progressive difference: Shows dimmings Show EIT wave The Moving Sun
  166. 166. Waves on the Sun In these images obtained by substraction of the previous one, one can better follow the gigantesque shock wave after a flare. SOHO/EIT The Moving Sun
  167. 167. CMEs: velocitis and acceleration 2 classes of CMEs (Sheeley et al. 1999): Gradual CME : Formed by the prominence and their cavities. Progressive Acceleration below 30 Rs Impulsive CME: Triggerred by the Flares. Associated to EIT waves. High velocity, constante or with deceleration. The Moving Sun
  168. 168. The Moving Sun
  169. 169. The Moving Sun
  170. 170. The Moving Sun
  171. 171. The Moving Sun
  172. 172. The Moving Sun
  173. 173. The Moving Sun
  174. 174. CMEs: latitude distribution Minimum (1996) Maximum (1999) The Moving Sun
  175. 175. CMEs HALO The most importnat class for solar tererstrial relation. Shocks source, SEP and geomagnetic perturbations. Frequency (sur base des fréquences globales et des distribution en latitude et en largeur): ~ 15% of all CMEs The Moving Sun
  176. 176. CMEs halo The Moving Sun
  177. 177. CMEs halo Progressive differences The Moving Sun
  178. 178. CMEs: modeles Basic elements to reproduce: the observations imply the shearing/torsion of magnetic field applyed along the neutral line on the photopsheric level, « carrying wrapping instability » (kink instability). 2 types of models: Analytical models: Quantittaive information about physical mechanisms. Difficult to reproduce observed morphology. Numerical Modles : Better reproduction of observations. Initial conditions must be known with high pression. Models in 2 parts: Fine grid for for the Corona (trigger) The Grid less dense for reproduction of propagation in the heliosphere. The Moving Sun
  179. 179. CMEs: sources and precursors Ejected filament is often twisted – helicity Energy storage in teh helicity. Unrolling of magnetic line during the propagation. (magnetic energy release). The Moving Sun
  180. 180. CMEs: precursors and helicity LASCO C2, 2/6/1998, 13h31 The Moving Sun
  181. 181. CMEs: precursors and helicity The Moving Sun
  182. 182. CMEs: modeles 5 categories of modeles: 1. Thermal deflagration 2. Dynamo 3. Mass loading 4. Rupture of connections ("tether release") 5. To put under the tension of connections (" tether straining") Syntheses of modellng: Low (2001), Wu et al. (2001). The Moving Sun
  183. 183. CMEs: modèles Lin et al. 2004 The Moving Sun
  184. 184. LASCO as the Comet hunter With the help of LASCO a thousand of new comets are discovered nowadays. SOHO/LASCO The Moving Sun
  185. 185. Solar Wind: the first indiexes First observations suggested the expanding medium in the solar system 19th century: Carrington (1879): correlation between whit elight flare and magnetic field measuremnt 2 days later.. Comet observation: gaz and dust tails always in out Sun direction (Biermann 1951). The Moving Sun
  186. 186. Solar wind: Velocity Profile Asymptotique velocity at long distance as the function of teh temperatur ein teh low corona : 200km/s at T= 0,5 x106 K 400 km/s at T= 1 x106 K 650 km/s at T= 2 x106 K It strats at 3 Rs (LASCO) Sheeley et al. 1998 The Moving Sun
  187. 187. Solar wind: acceleration Heating and acceleration of teh fast solar wind by MHD waves by the mechanism of the ion- cyclotron resonance. Different for slow wind (plasma confined in the closed field): Continous emergence continue of magnetic flux and opening by reconenction on teh top of the large scale loops. The Moving Sun
  188. 188. Solar wind: the source localization SOHO/SUMER: observation – doppler shift in NeVIII (77,0 nm, T= 650 000K) (cf. Hassler et al. 1997, 1999) Flux up l'extérieur (décalage vers la bleu shift ) dominating in the coronal holes. Maximum flux – on the trace of the border of the chromospheric network Correspondance with the underlying magnetic field structure. The Moving Sun
  189. 189. 189 The Moving Sun
  190. 190. 190 The Moving Sun
  191. 191. SECCHI suite 191 The Moving Sun
  192. 192. HI-1 CME 192 The Moving Sun
  193. 193. HI-1 CME-Venus 193 The Moving Sun
  194. 194. ICME at the Earth When CME achieve the Earth, it perturbs the terrestrial magnetic field. The Moving Sun
  195. 195. Polar Aurora The CME impact on the Earth trigger very often a geomagnetic storm, that can cause the polar aurora. The Moving Sun
  196. 196. Aurores Au passage d'un CME, injection renforcée d'énergie et de particules dans la magnétoqueue. The Moving Sun
  197. 197. Impacts sur l’environnement terrestre The Moving Sun
  198. 198. END That was only a flyover of the Sun, an exciting star in direct contact with our environment and One of the central research objective for the coming years The Moving Sun
  199. 199. Solar Space projects in near future The Moving Sun
  200. 200. SDO: AIA Central satellite of NASa program "Living with a Star" Launch: 2008-9 5 - 10 ans Orbite: geosynchronous (TB/day) The Moving Sun
  201. 201. SDO: AIA 3 instruments HMI: helioseismology, vector magnetograph EVE: spectro-photometre UV-EUV AIA: telescope EUV 7 wavelength The Moving Sun
  202. 202. Solar Orbiter / EUI: Extreme UV Imager Mission: Launch: 2013 5 - 7 ans Orbit: Distance to Sun: 0,21 AU (32 millions km, 45 Rs) Partially heliosynchronous Inclinaison: 30° Spatial resolution : 200 km The Moving Sun

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