Solar Orbiter
T.Appourchaux, L.Gizon and the SO / PHI team
derived from M.Velli's and P.Kletzkine's presentations

2nd Solar-C definition meeting, Tokyo, Japan

Content Science Objectives of Solar Orbiter Solar Orbiter mission and status
 Helioseismology, magnetic fields and PHI Solar Orbiter complementarity with other missions
 Conclusion

Why study the Sun-Heliosphere connection?

To answer How does the solar system work? ESAʻs CosmicVision Q2.
Sunʻs magnetized atmosphere and wind define planetary
space environments (CV Q1)
It is the site of universal phenomena which can be studied andunderstood in detail (CV Q3):
magnetic reconnection, collisionless shocks, turbulence
and collective nonlinear effects and energetic particle
acceleration
Science objectives

Solar Orbiter in short

Faster spacecraft
rotation rate
105 kmDynamical
reprocessing
0.2-0.3 AU
1 AU
Science objectives

Solar Orbiter Mission

 Solar Orbiter is the logical and timely next step afterUlysses and SOHO, combining remote sensing and insitu experiments.
 Solar Orbiter carries a dedicated payload of 10
selected remote-sensing and in-situ instruments
measuring from the photosphere into the solar wind.

Science objectives

How does the Sun create andcontrol the Heliosphere ?
Q1) How and where do the solar wind plasma andmagnetic field originate in the corona?
Q2) How do solar transients drive heliospheric variability?
Q3) How do solar eruptions produce energetic particle
radiation that fills the heliosphere?
Q4) How does the solar dynamo work and drive
connections between the Sun and the heliosphere?
Science objectives

Solar Orbiter Mission Overview
High latitude
Observations

Perihelion
Observations

Mission Summary
Launch date:

January 2017

Nominal Mission:

7.5 years

Extended Mission:

2.4 years

Orbit:

Elliptial orbit
0.23 – 0.29 AU (perihelion)
0.75 - 1.2 AU (aphelion)

High latitude
Observations

Mission and status

Out of Ecliptic View:

multiple gravity assists with Venus
to increase inclination out of theecliptic to >25 deg (nominalmission) >34 deg during theextended mission

Co-rotation:

2 periods of near-synchronization
with the Sun’s rotation per orbit,
allowing observations of evolving
structures on the solar surface &heliosphere for almost a complete
solar rotation

Solar Orbiter Mission status Payload selected back in 2008
 Preliminary Payload review held in end 2009-beg. 2010
 Solar Orbiter down selected in February 2010, together
with EUCLID and Plato (SPICA having a special status)
for Phase A/B1
 Two missions to be selected in mid-2011
 Start of Phase B1: early 2011
 Likely start of Phase B2/C/D: mid-2011
Mission and status

Solar Orbiter Payload
Investigation

Collaboration

Measurement

Solar Wind Analyzer (SWA)
PI C. Owen, UK

UK, I, F, Japan, D, CH, USA

SW ion & electron bulk properties, ion composition (1eV- 5keV electrons; 0.2 - 100 keV/q ions)

Energetic Particle Detector (EPD)
J. Rodríguez-Pacheco, Spain

Spain, D, FI, GR, CH, F, Slovakia,USA

Composition, timing, distribution functions of suprathermal energetic particles

Magnetometer (MAG)T. Horbury, UK

UK, A, I, H, D, F, E, DK, USA

DC vector magnetic fields (0 – 64 Hz)

Radio & Plasma Waves (RPW)
M. Maksimovic, France

France, SE, CZ, NO, UK, A, D,GR, AU, I, H, FI, Russia

AC electric and magnetic fields (~DC – 20 MHz)Polarimetric and Helioseismic Imager (PHI)S. Solanki, Germany

Germany, E, F, SE, NO, CH, AU,USA

Vector magnetic field and line-of-sight velocity in thephotosphere

EUV Imager (EUI)
P. Rochus, Belgium

Belgium, UK, F, D, USA

Full-disk EUV and high-resolution EUV and Lyman-αimaging of the solar atmosphere

Spectral Imaging of the Coronal Environment(SPICE) D. Hassler, USA

USA, UK, D, F, N

EUV spectroscopy of the solar disk and corona

X-ray Spectrometer Telescope (STIX)
A. Benz, Switzerland

Switzerland, PL, D, CZ, IRE, A,UK, F, USA

Solar thermal and non-thermal x-ray emission (4 – 150 keV)

Coronagraph (METIS/COR)
E. Antonucci, Italy

Italy, CK,F, D, GR, USA

Visible, UV and EUV imaging of the solar corona

Heliospheric Imager (SolOHI)
R. Howard, USA

USA, Belgium, UK, Germany

White-light imaging of the extended corona

Mission and status

Q4) How does the solar dynamo
work and drive the connections
between the Sun and the heliosphere?

4.1) How is magnetic flux transported to andreprocessed at high solar latitude?
4.2) What are the properties of the magnetic fieldat high solar latitudes?
4.3) How does the solar dynamo work?
Helioseismology and magnetic field4.1) How is magnetic flux
transported to and reprocessedat high solar latitude?
?

 Detect flows at and below
the solar surface, inparticular at high latitudes
 Most important flows are:
 Differential rotation
 Meridional circulation

Helioseismology and magnetic field4.2) What are the propertiesof magnetic fields at high solar
latitudes?

At 27o magnetic measurement is far improved. Granulation tracking can now follow largescale flows.
Helioseismology and magnetic field4.3) How does the solar dynamo work?
 SO can probe the tachocline at low / medium latitudes
 Solar-cycle variations at high latitudes
 Joint observations with SDO, GONG (long time series) : probe
deep interior; very high potential with Plan-A !

Helioseismology and magnetic fieldSO/PHI: Polarimetry and helioseismology

 Provide B to EUV imagers and spectrometer (linkage science) First proper view of magnetic and velocity field at the poles Stereoscopic helioseismology to probe the deep interior
 Stereoscopy of the photosphere Provide magnetic context for Solar Probe plus S/C ressources: 30 kg, 31 W, 20 kbps
Helioseismology and magnetic fieldSO/PHI instrument concept
 Solar radial velocity and vector magnetic field (absorption line) High Resolution Telescope (HRT): FOV: 16.8 arcmin, 1" arcsec resolution (0.5" pixel, 95 kms at
0.28 AU) Full Disk Telescope (FDT): FOV: 2.6 deg, 9.3" arcsec resolution (4.6" pixel, 930 kms at
0.28 AU) FDT and HRT used in sequence on different part of the orbit
SO / PHI

SO/PHI sub-systems
 Entrance window (14-cm diameter)
 HRT / FDT
 Off-pointing mechanisms
 Image Stabilization System (to 0.02 arcsec rms)
 Polarization Modulation Package
 Feed select (HRT or FDT) Filtergraph (Fabry-Perot) Focal Plane Assembly E-box
SO / PHISO / PHISO / PHI

Potential Synergy with Other Missions:
Solar Probe Plus
Joint NASA-ESA Solar Orbiter Solar Probe Assessment ʻ09

Enhanced science from mutual context / alignments

Solar Orbiter complementarity
Inclination(deg)Minimum
distance(AU)Duration above
30 deg per orbit(days)

Velocity

Magnetic fieldResolution(kms)

SOIYesLongitudinal300070.920GOLF

YesLongitudinalNone

70.920

BFI

Yes

Vector14070.970

NFI

Yes

Vector210

70.970SDO

HMI

Yes

Vector750

70.970SOLO

PHI (HRT)

Yes

Vector190

350.28~15 (perihelie)

PHI (FDT)

Yes

Vector1800

350.28~40MAG

N/A

Yes

N/A

35

0.28~40

Plan-A

DSI

Yes

Vector750> 40

1150

Solar probe +In-situ

N/A

Yes

N/A

3.4

0.040Mission
SOHO

HinodeInstruments

 High resolution velocity and magnetic field of the poles with SO / PHI Solar Orbiter has both in-situ and remote sensing instruments
 Ideal for linking with any in-situ only mission or remote-sensing only mission

Conclusion
Solar Orbiter answers the Cosmic Vision question"How does the solar system work?" : Exemplified by the theme of Sun-Heliosphere Connection: Solar
Orbiter will reveal how the Sun creates and drives the heliosphere.
 The selected payload is optimized to answer the mostfundamental science questions of solar and heliospheric physics
 Solar Orbiter will be launched in 2017, in synergy with Solar
Probe Plus, and hopefully Plan-A Plan-A ideal for 3-D stereoscopic helioseismology !