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Astrophysics and Solar Physics

Astrophysics and Solar Physics



AACIMP 2009 Summer School lecture by Elena Podladchikova.

AACIMP 2009 Summer School lecture by Elena Podladchikova.



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    Astrophysics and Solar Physics Astrophysics and Solar Physics Presentation Transcript

    • Royal Observatory of Belgium Our Dynamic Star Elena Podladchikova The Moving Sun
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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 solar structures are little variable. Active Sun: Variable phenomena. Brutal local deviations and transitory variations with respect to the quiet Sun. The Moving Sun
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • Photosphere: faculaes More hot regions The Moving Sun
    • 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
    • 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
    • Sunspot Dynamics (Dutch Open Telescope) The Moving Sun
    • 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
    • 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
    • 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 magnetogram at right), that change continuously. The Moving Sun
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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 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
    • 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
    • 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
    • Exterior Atmosphere Chromosphere and Transition Region The Moving Sun
    • 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
    • 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
    • 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
    • Atmopsheric Model Coronal heating problem: why is the corona so hot? Vertical profile of temperature and density in the Solar atmosphere The Moving Sun
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • Ejection +30 km/s The Moving Sun
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • Transition region: structures / temperature SOHO/SUMER, CIV SOHO/SUMER, SVI SOHO/EIT, HeII, 30,4 nm, T= 8 x105 K The Moving Sun
    • 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
    • Transition region: topology The Moving Sun
    • 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
    • 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 Moving Sun
    • 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
    • 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
    • Corona: limb brightenings SOHO/SUMER Si VI SOHO/SUMER C IV SOHO/EIT Fe XI The Moving Sun
    • 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
    • The Solar cycle The Moving Sun
    • The Solar Cycle: magnetic field and X-Ray. 1992 1999 Yohkoh Soft X-ray Kitt Peak magnetograms The Moving Sun
    • 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
    • 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
    • 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
    • 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
    • The Coronal Loops Basic elemnts of quit and active Corona. Closed B. Keeping of coronal plasma. The Moving Sun
    • 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
    • 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 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
    • 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 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
    • 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
    • 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
    • Solar Flares: classification Reference measurment, GOES: The Moving Sun
    • Solar Flares: morphology and et dynamics Mechanism: magnetic reconnection Observed emmisons come from difefernt layers. 16/8/2002, USET, ORB The Moving Sun
    • 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
    • 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
    • Lattice model (since 1991) 92 The Moving Sun
    • 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
    • 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
    • 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
    • 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
    • Intermediate Driving Scales of coronal heating Inverse cascade by – effect 97 The Moving Sun
    • 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
    • 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 near the surface. internal source of magnetic field. Include alpha-effect in the induction equation: 101 The Moving Sun
    • 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
    • Dynamics: chromosphere The Moving Sun
    • Dynamics: chromosphere The Moving Sun
    • Dynamics: chromosphere Frequent appearance and eruption of bright double ribbon and neutral line. The Moving Sun
    • Waves on the Sun A flare trigger a Sunquake SOHO/MDI The Moving Sun
    • Dynamique: chromosphère Fast magnetsonic shock propagation (Moreton wave) Associated to strong flares. V ~ 1000 km/s The Moving Sun
    • 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 The Moving Sun
    • Dynamics: Corona (Extreme UV) Flare sequence d'éruptions Octber -November 2003 SOHO/EIT: 19,5nm, T= 1,5x106K The Moving Sun
    • Dynamics: Corona (X and Rays) RHESSI: first images in X and rays Primary source of heat during impulsive phase. The Moving Sun
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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 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
    • 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
    • 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
    • EIT waves: dimmings Plasma evacuation Magnetic lines opening Arcade post-éruption Association to CME. Double dimmings (tranient coronal holes) The Moving Sun
    • Ondes EIT: déflection (TRACE) 19,5 nm (FeXII) 17,1 nm (FeX) H Ly (121,6 nm) Images Différences The Moving Sun
    • 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
    • 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
    • Trigger by wave front Coronal shocks (Thompson, 1998) 125 Th M vin S n e o g u
    • 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
    • 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
    • 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
    • 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
    • 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
    • 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
    • EIT wave front rotation EC EC front front dimmings dimmings Podladchkova and Berghmans 2005 The Moving Sun
    • 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
    • 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
    • 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
    • Cup of Coffee Analogy High cup borders close from our view the correspondent bottom parts The Moving Sun
    • CMEs 3D Studies Simultanious View STEREO - A STEREO - B The Moving Sun
    • 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
    • WHI STEREO-A DETECTIONS STEREO- 30 March Event of dimming intensity The Moving Sun
    • 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
    • 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
    • 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 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
    • Coronal Mass ejection During Flares, big plasma clouds are often ejected from the Sun, producing Coronal Mass Ejection. SOHO/EIT The Moving Sun
    • Coronal Mass-Ejection (CME) SOHO/LASCO The Moving Sun
    • 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
    • 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
    • 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 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
    • 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
    • ICMEs: Sursauts radio Type II burst (hectometric and kilometric band, 20 - 1000 kHz) Measured only out of terrestrial atmopshere The Moving Sun
    • 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
    • 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
    • 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
    • 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
    • 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
    • CMEs: propagation The Moving Sun
    • 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
    • CMEs: 18 October - 7 november 2003 Periode of very strong activity in 2 active regions (EIT: Fe XII, 19,5 nm) The Moving Sun
    • 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. The Moving Sun
    • 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
    • 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
    • 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
    • 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
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    • 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 perturbations. Frequency (sur base des fréquences globales et des distribution en latitude et en largeur): ~ 15% of all CMEs The Moving Sun
    • 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 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
    • 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
    • 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 ("tether release") 5. To put under the tension of connections (" tether straining") Syntheses of modellng: Low (2001), Wu et al. (2001). The Moving Sun
    • CMEs: modèles Lin et al. 2004 The Moving Sun
    • LASCO as the Comet hunter With the help of LASCO a thousand of new comets are discovered nowadays. SOHO/LASCO The Moving Sun
    • 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
    • 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
    • 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
    • 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
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    • 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 terrestrial magnetic field. The Moving Sun
    • Polar Aurora The CME impact on the Earth trigger very often a geomagnetic storm, that can cause the polar aurora. The Moving Sun
    • Aurores Au passage d'un CME, injection renforcée d'énergie et de particules dans la magnétoqueue. The Moving Sun
    • 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 environment and One of the central research objective for the coming years The Moving Sun
    • 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/day) The Moving Sun
    • SDO: AIA 3 instruments HMI: helioseismology, vector magnetograph EVE: spectro-photometre UV-EUV AIA: telescope EUV 7 wavelength The Moving Sun
    • 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