European and French solar physics from space

Jean ARNAUDLaboratoire FIZEAU

Observatoire de la côte d’AzurUniversité de Nice Sophia Antipolis

Introduction

Space Solar Physics is a very active field of research in many countries including the US, Europe and Japan.

A strong tradition of international cooperation exist here.

Observing programs can be proposed by scientists world while on almost all solar physics missions and data generally

become public domain very soon.

I will present major missions the European community is largely involved in, like SoHO, STEREO, HINODE and SDO and two

smaller missons: PICARD and SMESE

Solar and Heliospheric Observatory (SoHO)

Main goals of the SOHO mission: study the internal structure and outer atmosphere of the Sun, as well as the origin of the solar wind.

12 Instruments for the study of:-Corona and solar wind -Helioseismology- Solar constant- In situ particules measurements

an ESA/NASA Observatory launch on December 2 1995Still working very well after 12 years of mission

SoHO 12 Instruments Acronym

Coronal Diagnostics Spectrometer CDS

Charge, Element, and Isotope Analysis System CELIAS

Comprehensive Suprathermal and Energetic Particle Analyzer COSTEP

Extreme ultraviolet Imaging Telescope EIT

Energetic and Relativistic Nuclei and Electron experiment ERNE

Global Oscillations at Low Frequencies GOLF

Large Angle and Spectrometric Coronagraph LASCO

Michelson Doppler Imager/Solar Oscillations Investigation MDI/SOI

Solar Ultraviolet Measurements of Emitted Radiation SUMER

Solar Wind Anisotropies SWAN

Ultraviolet Coronagraph Spectrometer UVCS

Variability of Solar Irradiance and Gravity Oscillations VIRGO

CDS monochromatic imagesChromosphere and Corona

Loops at different temperatures in the same solar atmosphere region observed by CDS

• SUMER Observation of a coronal hole

10 000 K C I 124.9 nm

30 000 K S II 125 nm

190 000 K N V 123.8 nm

250 000 K O V 62.9 nm

1 100 000 K Mg X 62.4nm

1 400 000 K Fe XII 124nm

VIRGO complements 3 solar cycles of solar

irradiance measurements

Tornado in the Fe XI corona

(about 1 million K), EIT Observation

Wave propagating in the 1.4 MKlow corona

observed in Fe XII

Post flare waves propagating in

the photosphere (MDI observation)

The magnetic carpetdriven by near solar surface dynamos

Thousands of magnetic field loops over the photosphere, enough energy to heat the corona

Coronal Masses Ejections (CMEs)

• CMEs are linked to flares (energetic particules events) and eruptives prominences for at least 75% of them.

• CMEs are triggered by magnetic field instabilites.• Waves in the low corona can be associated to CMEs

(EIT)• Most CMEs originate from the chromosphere (EIT and

LASCO)• SoHO (UVCS) demonstrated that the CME is colder than

the corona (prominence material).

. Flux cancellation creates twisted flux ropes (Amari et al., 2007)

SoHO/LASCO C2 Active corona and CMEs

SoHO/LASCO C3 CMEs and protons shower

Open questions concerning CMEs

• CMEs result from magnetic field instabilities but we do not know the precise mechanisms which trigger and accelerate CMEs.

• We do not know why and how CMEs are linked to flares and prominences.

• We do not know the actual 3D geometry of CMEs

MDI deep interior of the Sun speed of sound determination

In red sound travels faster than theoretical prediction, implying higher temperaturesthan expected; in blue lowerthan expeted temperatures.

The shear layer between the radiative and the convection zones, where most of the solar magnetic field is generated, ishotter than expected.The solar core is 0.1% cooler than the standard model Sun.

MDI determination of the solar interior rotation rate

Subsurface structure above a sunspot as derived from MDI measurements

Upper convectionzone mapped from MDI observations

HINODE Solar ObservatoryLaunch in September 2006

• Hinode is a japanese mission with important US and UK participation.

Hinode (Solar-B) is equipped with three advanced solar telescopes.

Its solar optical telescope (SOT) has an unprecedented 0.2 arcsec resolution for the observation of solar magnetic fields.

The X-ray telescope (XRT) image the corona with a resolution of three times as high as Yohkoh (Solar-A).

The EUV imaging spectrometer (EIS) has very high sensitivity

SOT G-Band (420 nm) movie

Movie made from SOT images showing prominences above an active region at the limb. Detailed analysis of those high-resolution (0.25 arcsec) images in the visible attributes the waving motion of

a prominence to Alfvén waves in the corona.

Hinode X-Ray telescope observation of soft X-ray corona for one solar rotation

X-ray corona and G band photosphere

STEREO MISSIONLaunch in October 2006

• This two-year mission employs two nearly identical space-based observatories - one ahead of Earth in its orbit, the other trailing behind - to provide the first-ever stereoscopic measurements to study the Sun and the nature of its coronal mass ejections, or CMEs.

• STEREO's scientific objectives are to:• Understand the causes and mechanisms of coronal mass ejection

(CME) initiation. • Characterize the propagation of CMEs through the heliosphere. • Discover the mechanisms and sites of energetic particle

acceleration in the low corona and the interplanetary medium. • Improve the determination of the structure of the ambient solar wind.

                                

Sun Earth Connection Coronal and Heliospheric Investigation(SECCHI)   

four instruments  mounted on each of the two STEREO spacecraft

- an extreme ultraviolet imager (EUVI)- two white-light coronagraphs COR1: Inner Coronagraph and COR2: Outer Coronagraph - a heliospheric imager (HI)

These instruments will study the 3-D evolution of CME's from birth at the Sun's surface through the corona and interplanetary medium to its eventual impact at Earth.

The Heliospheric imager

• The HI-1 and HI-2 telescopes are set to 13.98 and 53.68 degrees from the Sun, along the ecliptic line, with fields of view of 20 and 70 degrees, respectively. This provides on overlap of about 5 degrees.

Stereo COR2 vision of a CME a CME early phase seen both edge & face-on

A. Vourlidas

COR2 A and B 2 to 15 solar raduis field

CMEs and waves in the fields of vue of COR2, HI-1 and HI-2

Solar Dynamics ObservatoryTo be launched in August 2008

NASA Mission with international participation

• HMI (Helioseismic and Magnetic Imager) – The Helioseismic and Magnetic Imager will extend the capabilities of the

SOHO/MDI instrument with continuous full-disk coverage at higher spatial resolution.

• AIA (Atmospheric Imaging Assembly)

– The Atmospheric Imaging Assembly will image the solar atmosphere in multiple wavelengths to link changes in the surface to interior changes. Data will include images of the Sun in 10 wavelengths every 10 seconds. Will extend the capabilities of TRACE: same spatial resolution,larger field.

• EVE (Extreme Ultraviolet Variablity Experiment) – The Extreme Ultraviolet Variablity Experiment will measure the solar

extreme-ultraviolet (EUV) irradiance with unprecedented spectral resolution, temporal cadence, and precision. Measures the solar extreme ultraviolet (EUV) spectral irradiance to understand variations on the timescales which influence Earth's climate and near-Earth space.

THE PICARD satelliteA CNES (French space agency) mission

with Belgium and Swiss participationTo be launched in June 2009

  Three instruments SODISM measures the solar shape and diameter. SOVAP measures the total solar irradiance.   PREMOS measures irradiance in four spectral domains and the total solar l'irradiance.   

  

1999

Début

Doraysol

959,20

959,40

959,60

959,80

2000 4000 6000 8000 10000 12000 14000 16000

SUNSPOT(Ech. arbitraire)

DEMI-DIAMETRE Obs.: F. LACLARE (40 Mesures au znith)

ACTIVITE PREVISIONNELLE

DATE JJ :(2440000 +)

ASTROLABE SOLAIRE CALERN: (1978 - 2006)

1980 1985 199O 1995 2000 2005 2010

30 years of ground based solar diameter measurements

Authors Location Cycle Amplitude (mas)

duration Meth./Inst.

Ulrich, 1995 Mt Wilson In phase 400 1982-1995 Scanning

Penna et al, 2002 Rio - 0 1998-2000 Astrolabe

Noel, 2003 Santiago In Phase 1000 1991-2002 Astrolabe

Sveshnikov, 2004 In Phase 500 1631-1973 Transit de Mercure

Delmas, 2002 Calern Opposition 200 1978-2004 Astrolabe

Sofia et al., 1985 Opposition 470 1925/1979 Eclipses

Brown, 1998 HAO - 0 1981-1987 Méridien

Wittmann, 2003 Tenerife - <50 1990-1992 Méridien

G. Thuillier

Ground based solar radius measurements situation

Lack of constitency between results due to:

- Diameter definition

- Quality of measurements

- Spectral domains (Fraunhofer lines)

- Data processing

- Atmospheric (seeing) effects

SODISM (SOlar Diameter Imager and Surface Mapper) is a telescope, inside a temperature stabilized carbone-carbone structure, 11 cm in diameter, a filter system and a 2048 x 2048 CCD. SODISM will measure the solar diameter in three spectral regions at 535, 607 and 782 nm free of Fraunhofer lines.

SODISM Optical design

4 prisms in a ring at the telescope entrance give 4 auxiliary solar images usedfor guiding and for calibration of the telescope focal length.The aim of SODISM is to get a precision of about 1 milliarcsec on the diameter measurement. This mean that the focal length has to be know with a relativeprecision of 10-6.

PICARD scientific objectives

- Precise measurement of the solar diameter and of its variations (if any) with the solar cycle phase and determine if solar diameter

variations are linked to the solar activity.

- Determine with the help of PicardSol (a SODISM copy + a atmospheric monitor on ground) if the solar diameter can be monitor

using groung based instruments.

- Help to understand the effect of solar activity on climate. The Maunder minimum (1645–1715) of solar activity did correspond to a ‘little ice age” in Europe and America. Jean Picard (1620-1682) measured the solar diameter. It was 1 arc sec larger than its present value.

The Small Explorer for Solar Eruptions (SMESE)

A French-Chinese cooperation in solar PhysicsTo be launched in 2013

China: PMO : Purple Mountain Observatory, CAS

NJU : Nanjing University CSSAR : Center for Space Science and Applied Research

(Beijing)NAOC : National Astronomical Observatory, CAS (Beijing)

CNSA : Chinese National Space Agency

France : LESIA/OP : Laboratoire d’Etudes Spatiales et d’Instrumentation

en Astrophysique (Paris Observatory)IAS : Institut d‘Astrophysique Spatiale (Orsay)

CNES : Centre National d‘Etudes Spatiales

Collaborations with other Institutes (LAM, LPCE, MPS, Torino/Firenze, CSL, Brazil, ...)

SMESE Instrumentation

- LYOT: LYman imaging Orbiting TelescopeA Ly coronagraph & disk imager with high

cadence (~10 s), high sensitivity and polarimetric capability

- DESIR: Detection of Eruptive Solar InfraRed emission A Far IR telescope performing photometry and

source localisation to catch synchrotron (particles) and thermal (chromosphere) radiations : a first

- HEBS: High Energy Burst Spectrometer A HXR & gamma-ray spectrograph over an

unprecedented energy range, going well above the RHESSI limit (10 MeV) : 10 keV – 600 MeV

Conclusion• Solar Physics from Space is a very active area of research • SoHO and succeeding missions are giving a new vision of the Sun,

demonstrating how active is its atmosphere and how its influences the earth environment. They are giving new insights on the solar interior and its rotation, on the solar wind acceleration, on flares and CMEs, on the origins of the magnetic field among many other things.

• Those missions also emphasized the importance of the magnetic field for heating the solar corona, accelerating the solar wind, triggering flares and CMEs ejections. Even if we still miss the detailed mechanisms at the origin of a large part of those phenomenon, progress in solar physics are very important.

• Improving spatial resolution and determining the magnetic field in the full solar atmosphere are keys for further improvements in understanding the physics of our star.

The Milky Way in the HI 1 A

field

Field of 14 degres

centered 20 degres from

the Sun

A very active Sun

CMEs impact the magnetosphere (CLUSTER)

SOT observation of a prominence

A movie of a coronal active region above the Sun « surface », close to an equatorial coronal hole. Looking to the left of center in the sequence of

images, an outflow of material (plasma) was measured to be movinng at 10 km/s. Material outflow in regions like this one, is thought to be a source of the

low-speed solar wind.

High-speed solar wind has speeds of 600-800 km/s.

Soft X-Ray active region followed 12 days

Hinode Soft X-Rays telescope

Mercury as seen by the two COR1 telescopes

The planet Mercury as seen by the two COR1 telescopes on May 3, 2007.Also shown is the calculated position and size of

the solar disk.

Heliospheric imager (HI) Optical flow observation