T. Horbury, 12 Sep 2011 - Solar Orbiter Science Pages

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Solar Orbiter
Exploring the Sun-heliosphere connection
Science questions
Mission overview
Status update
The Sun creates the heliosphere
Why study the Sun-space connection?
• Addresses ESA’s Cosmic Vision question “How does the solar
system work?”
• Study plasma phenomena which occur throughout the
Universe
– Shocks, particle acceleration, magnetic reconnection,
turbulence, etc.
– Also addresses Cosmic Vision question “What are the
fundamental physical laws of the Universe?”
• Solar wind and energetic particles directly affect life on Earth
– Impact on space and ground-based assets
• Builds on European heritage: Ulysses and SoHO
The need for near-Sun observations
Distance
In-situ density
Solar Orbiter
Solar Orbiter
1
2
3
4
Days
5
6
• Solar wind is
variable and
structured
• Originates in
polar coronal hole
complex
magnetic
“carpet”
• Small scale
transient jets
are common
coronal funnel
• Solar Orbiter will measure the spatial and temporal variability
of the solar source and solar wind in unprecedented detail
Tu, Zhou, Marsch et al., Science 2005
How and where do the solar wind plasma
and magnetic field originate in the corona?
Linking Sun and the solar wind
• We need to measure the same
parameter on the Sun and
in space to make the link
– Heavy ion charge states and
composition
– Magnetic polarity
– Energetic particles
• Solar Orbiter will make all of these
measurements with both remote
sensing and in situ instruments
He+
H+
How do solar transients drive heliospheric
variability?
• How are substructures
of coronal mass
ejections related to
interplanetary
transients?
• How are CMEs
processed as they
travel from the Sun?
• Solar Orbiter will
image CMEs and
measure their
evolution in the inner
heliosphere
Coronal mass ejections in space
How do solar eruptions produce energetic
particle radiation?
• Around 10% of coronal
mass ejection energy is
in accelerated particles
• Understanding release
and transport
mechanisms requires
going close to the Sun
• Solar Orbiter will
measure energetic
particles within a mean
free path of their
acceleration site
0.3 AU
1.0 AU
How does the
solar dynamo work?
• The unexplored poles are central
to the operation of the Sun’s
dynamo
• Solar Orbiter will
provide the first
accurate
measurements of
polar flows and
magnetic fields
The Sun has changed
What is required
•
•
•
•
•
Close to the Sun
Out of the ecliptic
Long duration observations of the same region
Remote measurements of the Sun and corona
In situ measurements of fields and particles
• It is this unique combination provided by Solar Orbiter that
makes it possible to address the question of how the Sun
creates and controls the heliosphere
Summary
Carefully optimised payload of ten remote
sensing and in situ instruments
Launch: January 2017
Cruise Phase: 3 years
Nominal Mission: 3.5 years
Extended Mission: 2.5 years
Perihelion: 0.28 – 0.3 AU
Fast perihelion motion: solar features visible
for almost complete rotation
Out of ecliptic: first good view of solar poles
Mission profile
Solar Orbiter spacecraft
• Three-axis stabilised, Sun pointing
• Heatshield at front
• Re-use of BepiColombo
unit designs as practical
• Mass: 1750kg
• Power: 1100W
• Launch: ELV
In situ instruments
SWA
Solar wind analyser
Chris Owen, UK
Sampling protons, electrons and heavy ions in
the solar wind
EPD
Energetic particle detector
Javier RodriguezPacheco, Spain
Measuring timing and distribution functions
of accelerated energetic particles
MAG
Magnetometer
Tim Horbury, UK
High-precision measurements of the
heliospheric magnetic field
RPW
Radio and plasma wave
analyser
Milan Maksimovic,
France
Studying local electromagnetic and
electrostatic waves and solar radio bursts
Remote sensing instruments
PHI
Polarimetric and
heliospheric imager
Sami Solanki,
Germany
Full-disc and high-resolution visible light
imaging of the Sun
EUI
Extreme ultraviolet imager
Pierre Rochus,
Belgium
Studying fine-scale processes and large-scale
eruptions
STIX
Spectrometer/telescope for
imaging X-rays
Arnold Benz,
Switzerland
Studying hot plasmas and accelerated
electrons
METIS
Multi-element telescope for
imaging and spectroscopy
Ester Antonucci, Italy
High-resolution UV and extreme UV
coronagraphy
SoloHI
Solar Orbiter heliospheric
imager
Russ Howard, US
Observing light scattered by the solar wind
over a wide field of view
SPICE
Spectral imaging of the
coronal environment
Facility instrument,
ESA provided
Spectroscopy on the solar disc and corona
SPICE and SIS
• ESA tasked external review committee to study scientific
impact of NASA decision not to support SPICE and SIS
• Committee urged ESA to investigate ways to recover
measurement capabilities of SIS and SPICE
SPICE – UV imaging spectrograph
• Returns 2D high resolution spectral
images
– Intensity, Doppler shift, line width
– Complete temperature coverage from
chromosphere to flaring corona
• Provides remote characterisation of
plasma properties near the Sun
• Map outflow velocities and composition
of surface features to solar wind
structures
SPICE - status
• Proposal exists for provision of SPICE instrument
• Retains Red Book capabilities
– Full on disk capabilities
– Off-limb up to 1.3 solar radii
– METIS augments this with off-limb spectroscopy beyond
1.3 solar radii
• All mission science goals achieved
SIS – Supra-thermal ion spectrograph
• Measures supra-thermal
heavy ions
• Part of EPD suite
• Covers energy range
between solar wind and
energetic particles
• Explores near-Sun ion pool,
plus flares and shocks
SIS - status
• Proposal exists for provision of SIS instrument
• Retains Red Book capability
• All mission science goals achieved
High-latitude
remote sensing
Perihelion
remote sensing
High-latitude
remote sensing
Science windows
• Orbit: 150-168 days
• In situ instruments on at all times
• Three science “windows” of 10
days each
• All remote sensing instruments
operational
• Observing strategies based on
science targets
– Active regions, coronal hole
boundaries, flares, high speed
wind, polar structures
• Autonomous burst mode triggers
for unpredictable events
• Telemetry and mass memory
tailored to return planned
instrument data volumes
Links to Solar Probe Plus
• Many conjunctions will
occur between Solar
Orbiter and Solar Probe
Plus
– Extends science
return from both
msisions
• Solar Probe Plus is not
required for any Solar
Orbiter science goal
Solar Orbiter
• Answers the Cosmic Vision question “How does the solar
system work?”
• Unique combination of orbit and instruments
• Selected payload is optimised answer the most fundamental
questions of solar and heliospheric physics
• Timely, mature and well studied mission with compelling
scientific objectives

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