SOLAR-C mission
Saku Tsuneta (NAOJ/JAXA)SOLAR-C working group
January 31, 2008

Solar physics from space in Japan
Yohkoh (1991- 2001)
With NASA/PPARC

Hinotori(1981-1982)
Hinode (2006-) with NASA/STFC/ESASOLAR-C

2010-192

Tansei(Pathfinder mission)

Solar physics fromspaceinJapan
With NASA, UK
With NASA, UK

Hinotori (ASTRO-A)
188 kg, 1981

Yohkoh (SOLAR-A)
390 kg, 1991

Hinode (SOLAR-B)
Non-thermal acceleration
・Hard-Xray imaging with Non-thermal acceleration ~ 900kg, 2006
and plasma heating
Magnetic fields with corona
rotation modulation
・HXR Fourier telescope (J) ・SOT (Japan, US)collimator 10 arcsec
7 arcsec
0.2 arcsec
・Bragg crystal spectrometer
・Soft X-ray telescope (J/US) ・XRT (US, Japan)
・SXS, HXS
5arcsec2arcsec・Bragg spectrometer
・EIS (UK, US, Japan)(J, US, UK)
2arcsec・WBS
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Solar Physics from Space in Japan• Strong support from X-ray astronomers inHinotori and Yohkoh missions• Heritage of suborbital (sounding rocket andballoon) programs at NAOJ (U. Tokyo)• Merge space and ground-based optical people
to form one team for SOLAR-B• With successful completion of SOLAR-B, solar
physics reached critical mass to implement amajor mission in stand-alone mode if withinternational collaboration.
4Hinode (SOLAR-B) mission objective: systems approach tounderstand generation, transport and ultimate dissipation of solar
magnetic fields with 3 well-coordinated advanced telescopes.
Solar Optical Telescope（SOT） EUV Imaging
0.2 arcsec vector-magneticand photometric images

Spectrometer（EIS）
LOS velocity and turbulence maps
at log T = 4.7, 5.4, 6.0 - 7.3 K,
Sensitivity ~1% of Alfven velocity

X-ray Telescope（XRT）
Sensitive to 1-10MK
1arcsec resolution withhigh cadence

Launched on Sep 23, 2006 by JAXA
Japan-US-UK-ESA project
Mission Lifetime: > 3 years
Orbit: Polar, Sun Synchronous5

Solar-B chronology• 1994-1995 Ad-hoc working group at NAOJ
• 1995
Mission proposal (MUSES-C)• 1996
Mission proposal2 (IR-mission)• 1997
Mission proposal3 (finally won)==parallel activity in US and UK==
• 1998New start with basic research ¥• 1999-2001 Proto-model design/fab./test• 2001-2004 Flight-model design/fab./test• 2005-2006 Final test/launch• 2006
PV Observations start6

SOLAR-B science mission
design（1995-１９９7）• SOT：Modest 50cm diffraction-limited telescope,considering science requirement, technical and costreality.
• Stokes polarimeter is a must instrument (can not fly
only with filter instrument)• Needs velocity maps with EUV imaging spectrometer• Simultaneous observations with high co-alignment
accuracy• XRT: Choice of grazing incidence optics to havetemperature sensitivity in 1-20 MK, while maintaining
high spatial resolution• Once the concept was established, there has been nocompromise during the development.
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Strong international collaborationfor SOLAR-B
3 space agencies, 11 organizations in 4 countries
UK
MSSL(EIS)RAL(EIS)

NorwayUniv. Oslo(EIS)LMSAL (FPP)HAO(FPP)SAO(FPP)ESA

JAXAJapanUSNASANRL (EIS)

NAOJ
NASA GSFC(EIS)(OTA, FPP, XRT, EIS)
NASA MSFC(FPP, XRT, EIS)JAXA(Rocket, Spacecraft,OTA, FPP, XRT, EIS)

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9NAOJ/ATC Clean
Room for space optics
190m2 ,10mHighClass 100
Class 0-10 in the boothSpace-chamber, large opticalflat, fast interferometer, large
Newport table

Heliostat to introduce natural star and sun
light: Beam size 55 cm dia.
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OTA
FPP

OBU

SOT assembly and test at NAOJ/ATC11

Telescope integration andtest at NAOJ/ATC clean room

Telescope assembly

Thermal vacuum testUppershroudOTA

Dummy OBU

干渉計
SupportLower
shroudTelescope inclean room
illuminatedwith 50cm
sun beam

OTA alignment cube

flat mirror

shroudTilt/shift stage

Flat mirror
reference

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Optical performance test in orbit environment

XRT Camera Calibration Facility
at NAOJ/ATCX-ray Monochrometer

Vacuum Chamber

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XRT Camera Calibration Facility

X-ray monochrometer

EUV monochrometer

Shutter

55Fe

SSD

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SOLAR-B Flight model at ISAS

OTA
EIS

FPP

EIS

OTA

FPP

XRT

XRT

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SOLAR-C mission

Parallel investigation• Plan A: Out-of-ecliptic magnetic and helioseismic observations of solar polar region toinvestigate the internal structure and dynamo
mechanism of the Sun.
• Plan B：Higher resolution observations toinvestigate heating and dynamics of solar
atmosphere with UV-enhanced Hinode SOT plus
advanced spectroscopic capabilities• Request mid-2010 launch.
• Launch vehicle JAXA H-IIA.
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Plan A: Investigate the sun as a starthrough exploration of polar regions• Out-of-ecliptic observations on solar polar regions havenever been performed.
• Hinode is providing unprecedented view on the magnetic
landscape of the solar polar regions.
• Observing target includes– Helio-seismic observations on internal acoustic speed, angularrotation speed, meridional flow, and flux tube imaging– Magnetic observations on surface magnetic and velocity fields– Option: reach deep convection zone and tachocline with dual
satellite observations, using the methodology of local helioseismology.
– Option: in-site instruments

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Magnetic and velocity fluctuationsin the Solar Atmosphere
Granular motion
Elemental flux tube
Acoustic waves
Hot coronaSpicules
etc etc….

Rutten, R., ASP-CS, 184, 181, 1999

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Chromosphere more dynamic
than expected!

202006 Dec 17 20:00-21:00 UT CaII H broad band filter images taken with Hinode/SOT

Post-Hinode understanding
on solar atmosphere
Polar kG fields
Chromosphericjets due toreconnection

Waves in prominence

Slow solar windSupersonic downflow
Waves along spicules

Convective collapse

Penumbralmicro-jets

Magnetic velocity
Fluctuation

Ubiquitous
Horizontal fields

High coronalturbulence 21
Rutten, R., ASP-CS, 184, 181, 1999

Plan B：High resolution observations fromphotosphere to corona through interface region ofchromosphere and transition region•••

From imaging to spectroscopy: obtain precise information on dynamics suchas waves, thermal and MHD instabilities, reconnection and on magneticfields
From visible to UV: cover the entire solar atmosphere from photosphere tocorona through chromosphere and transition region
Strawman instruments– Visible-UV telescope （1300-8500Å）＞50cm diffraction-limited telescope （＜0.10.3arcsec） with advanced imaging and spectoscopic instruments– Ultra-high resolution EUV/X-ray telescope （100-1000Å）– Enhance high-resolution spectroscopic capability as compared with Hinode.

•Understanding on coronal and chromospheric heating and dynamics
through observations by combination of spectroscopic and imaging
instruments– Magnetic and velocity fields of photosphere and chromosphere– Wave, turbulence, magnetic reconnection, mode coupling of waves at β～1layer•

Progress on Hinode data analysis would affect the mission concept.
– For instance, remarkable dynamical phenomena of the chromosphere revealedby Hinode intensify interests on the plan B mission.

•Key technology for >50cm diffraction-limited telescope available due to
Hinode heritage22

End-to-end observations on
5000km-thick layer exhibiting
4000K-to-a few MK change
Hinode imaging observations
100万遷移層密 度

温度

Hinode imaging
observations reveal
unexpected highly
dynamic chromosphere・Chromosphere needs
x10 heating energy.
(K)・Not static atmosphere・Coronal heating may beclosely related to theinterface region between
the magneticphotosphere and thedissipative corona.

XRT
温 度

SOT

EIS

光 球

彩Gバンド

CaII H線

層コロナ

温 度

Spectroscopic observations with SOLAR-Ｃ

密 度

温度最低層
高さ (km)23

Plans A and B• JAXA SOLAR-C WG investigates science,technology, and other constraints withinternational teams for decision.
• Tradeoff and figure-of-merit for decision making– Science merit is always the major driver.
• Importance of deepening the Hinode science analysis– Feasibility of plan-A spacecraft and orbit critical– Technical feasibility for science instruments underconstraints– Consistency and synergy with NASA and ESA plans
24SOLAR-C and other ongoing missions
2010

2020

Solar maximum

CY

Solar maximum

HINODESOLAR-C
ATST（NSF)
SDO（NASA)
Solar Orbiter（ESA)

B案

2015 Feb.

A案

2015 Feb. Orbit trans2014
2008 Dec 08.
2015 May▲▲
2018 summer 2021 summer
reach obs-deck Helio-lat. 15 degree

Note１：Plan A orbit trans. period not accurate, being studied.
Note２：NASA decadal plan beyond SDO not available.
Note３：ESA SOLAR ORBITER reach 0.22AU on summer of 2018.

▲2022-23
Helio-lat. 35degree25

SOLAR-C launch opportunity(Not authorized by JAXA)• PLANET-Ｃ ２０１０
• HAYABUSA-II ２０１１
• ASTRO-G ２０１２
• NEXT 2013
• SOLAR-C 201426

Justification for mid-2010 launch• Plan A satellite has to reach a observing point around2018 to be ready for the solar maximum and polar fieldreversal.
• Joint observations with highly complementary missions– NASA SDO (whole sun field of view)– ESA Solar Orbiter• Continuity in solar physics research in Japan requires
mission approximately every 10 years– Hinode launched in 2006.
– Hinode science and data continue to be first grade upto solarmaximum around 2011.

• Avoid vacuum in solar physics: No similar mission yet
defined in NASA and ESA(?)
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SOLAR－C development schedule(under review by SOLAR-C WG andnot authorized by JAXA)• FY2014• FY201４• FY2012～13• FY2010～11• FY2009• FY2008• FY2007

Lauch〔2015 February〕
S/C tests
Flight modelProto model
JAXA phase-A
Select plan A or B
JAXA SOLAR-C WG
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SOLAR-C near-term calendar• 2007 October 16– Meeting with NASA HQ personnel (Washington D.C.)• 2007 December 18– Meeting with NASA HQ delegation led by Dr. Alan Stern (ISAS).

• 2007 December 27– SOLAR-C working group approved at ISAS space sciencesteering committee with recommendation to present one mission
again in one year

• 2008 Jan 30ーFeb 1– SOLAR-C－ESA Solar Orbiter science meeting in Lindau

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SOLAR-C Summary• Solar physics community in Japan has so far
developed 3 solar missions over past 25 years.
• Success of Hinode and Yohkoh is due to strong
US and European supports.
• Solar physics community and related-disciplines
in Japan strongly desire and endorse theSOLAR-C mission concept to be realized in mid2010.
• The JAXA SOLAR-C working group invites US
and ESA participation to the SOLAR-C program,following our remarkable history of collaboration.
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SOLAR-C organization• JAXA/ISAS working group– Chair Tsuneta– Vice chair Sakao, Shimizu, Watanabe• NAOJ SOLAR-C project office (proposed)– Head Hara
– Vice head Katsukawa

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