Lessons learned from IMaX spectropolarimeter and future perspectives. The Polarimetric Helioseismic Imager (SO/PHI) for the Solar Orbiter mission

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1 Lessons learned from IMaX spectropolarimeter and future perspectives The Polarimetric Helioseismic Imager (SO/PHI) for the Solar Orbiter mission Dr. Alberto Alvarez-Herrero Área de Cargas Útiles e Instrumentación

2 Introduction IMaX and SO/PHI were planned since 2001 Both projects have their own goals, although IMaX always was thought as an strategic step to acquire Technologic know-how: i.e. First spectropolarimeter in an aerospace mission developed in Europe Innovation: i.e. Polarisation modulators based on LCVRs, LiNbO 3 etalons as filtergraph Scientific excellence: supported by in-house technologic knowledge in order to achieve a privileged position in the SO/PHI development (Co-PI)

3 Introduction IMaX is a very successfully instrument by itself: Quality of scientific observations never achieved before The instrument description in Solar Physics journal is the paper most cited of the SUNRISE technical papers IMaX is the precursor of SO/PHI and it has the heritage of IMaX technology developments carried out by the Spanish Consortium

4 The SUNRISE mission The SUNRISE mission consisted of a stratospheric balloon, with a solar telescope of 1 m aperture onboard. It was successfully launched on June 8 th 2009 in the Artic, within the NASA Long Duration Balloon Program. The flight duration was 5 days and 17 hours The main scientific objective of SUNRISE is the study of the solar magnetic fields with high spatial resolution (100km in the solar surface) Post-focal instruments SUFI: SUNRISE Filter Imager IMaX: Imaging Magnetograph experiment CWS: Correlation Tracker and Wavefront Sensor Quality data and observation time never achieved before 2 nd flight:

5 SUNRISE: international consortium

6 IMaX description (and PHI description) IMaX is a solar magnetograph The spectral line is sensitive to the solar magnetic fields due to the Zeeman effect High sensitive polarimeter (<10-3 ) High resolution spectrometer (<70mÅ) Diffraction limited Imager(<0.14 arcsec)

7 IMaX description (and PHI description) λ (<1Å) t max< <30s Courtesy of J. C. del Toro Iniesta B ur For every pixel λ 1 S λ 2 S λ 3 S λ 4 S λ 5 S λ<0.070 Å

8 IMaX results

9 IMaX results

10 The SUNRISE-IMaX technological challenges The instrument requirements are very restrictive and the use of novel technologies as LCVRs and LiNbO 3 etalons are required. High restriction in the power and the mass budgets. Environmental conditions: Thermal stability: Active and passive thermal control, optical athermalization, thermo-elastic stiffness. Presure conditions: 3-7 mbar: Electrical discharges risk, heat transport mechanism (radiation and conduction, not convection), change of the focal plane position due to absence of atmosphere Mechanical vibrations and shock Automatic system (low telemetry bandwidth) Pointing system (<0.005 arcsec) To maintain the instrument and telescope optical alignment during the flight. Definition of the verification tests to be performed. They shall be resentative of the instrument operation during the flight, And many, many others

11 SUNRISE: El telescopio Carbon fiber based telescope structure with 1m Zerodur light weighted primary mirror (SAGEM, France) Industrial contract (Kayser-Threde,Munich) Gregory configuration (f/25, elliptic secondary) Field of view: 3.4 arcmin(150 Mm on the Sun)

12 IMaX-SUNRISE: description IMaX Imaging Magnetograph experiment ROCLIs M3 M2 etalon LiNbO 3 etalon in double pass configuration F4 Prefilter Beamsplitter Phase Diversity Etalon M1 High spatial resolution magnetograph FoV: 50 x nm Spectral resolution: 60mÅ Full Stokes vector images every 30s; (I,V) every 5s 2 CCDs for crosstalk elimination Phase diversity LCVR CCDs MM X Liquid Crystal Variable Retarders LCVR prefilter

13 IMaX: as built

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18 Lessons learned from IMaX General conclusions The great importance of the AIV phase: more time should be planned and dedicated to AIV phase because it allows a deep knowledge of the instrument. This will be crucial during the operation phase. A deep knowledge of critical and/or novel subsystems is crucial against unforeseen events or conditions: to promote PhD. Thesis in space instrumentation. Over-engineering: budgets with excessive margins are so bad as budgets without margins. Specific technical conclusions Thermal behaviour of etalons Etalons polishing-degree effects on image quality Polarisation efficiencies close to the theoretical maximum ones can be achieved using LCVRs High voltage management at low (but not too low) pressure (3-7mbars)

19 First results 4 Mission and Instruments papers SP ApJ Letters 1. Resolved Network Points (kg field) IMaX 2. Zero microtubulence regions IMaX 3. Vortex flows observed in line parameters IMaX 4. Horizontal vortex tubes IMaX 5. Horizontal IN fields lifetime IMaX 6. Supersonic upflows from reconnections IMaX 7. Exploding granules and f-mode oscillations IMaX 8. Far more accoustic power for heating IMaX 9. BP contrast in the nm IMaX & SUFI 10. Granular contrast in the nm SUFI 11. Resolved structure in IN loops IMaX 12. IN points extrapolated to Network points IMaX 13. Introductory letter (mean fluxes) IMaX & SUFI

20 Solar Orbiter mission Solar Dynamics Space Weather Corona heating Magnetic fields Scientific goals: To determine in-situ the properties and dynamics of plasma, fields and particles in the near-sun heliosphere To survey the fine detail of the Sun's magnetised atmosphere To identify the links between activity on the Sun's surface and the resulting evolution of the corona and inner heliosphere, using solar co-rotation passes To observe and characterise the Sun's polar regions and equatorial corona from high latitudes

21 Solar Orbiter mission Technical implementation: ESA-NASA joint mission Launch 2017 (2018) AU Out of the ecliptic (>30º): the poles will be observed Co-rotation with the Sun Total duration (2017): 3612 days (9.9 years) Nominal Science Phase (2017): 1235 days (3.4 years)

22 SO/PHI consortium Germany Germany 49% Spain 41% Spain France Sweden Norway 1% Sweden 1% France 8%

23 SO/PHI organization chart

24 Functional diagram Dual beam + Correlation tracker

25 Spanish key contributions Full Disk Telescope PMP based on LCVRs Electronic box: RTE Etalons space qualification High visibility First time in the space Overall responsibility and innovation First time in the space Presentation SO/PHI, IAA-CSIC - Progress on the electronic inversion of the radiative transfer equation for SO/PHI Posters SO/PHI IDR/UPM - Thermal modeling of the SO/PHI instrument" SO/PHI UV - Software simulator of the SO/PHI instrument: SOPHISM SO/PHI UB - An Image Stabilization System for SO/PHI

26 SO/PHI Optical Unit

27 Full Disk telescope (INTA)

28 PMP based on LCVRs (INTA)

29 Validation of LCVRs for Solar Orbiter (INTA) GOAL: this activity aims at increasing the relevant technology readiness level in Europe from TRL4 Component Validation in Laboratory Environment to TRL5 Component Validation in Relevant Environment by providing a significant step towards full space qualification of high-performance LCVRs for the Solar Orbiter mission. APAN Anti-Parallel Aligned Nematic HAN Hybrid Aligned Nematic Wide Acceptance Angle Anti-Parallel Aligned Nematic Achromatic LCVRs Anti-Parallel Aligned Nematic 4 types 1 type 1 type 1 type 40 cells 10 cells 20 cell 20 cells TOTAL: 8 types, 90 cells 2 years of work SUCCESSFULLY FINISHED on May 2011 ESA contract No.22334/09/NL/SFe Validation of LCVRs for Solar Orbiter PMP

30 Validation of LCVRs for Solar Orbiter (INTA) Spain leads the use of liquid crystals for polarisation measurements in space applications. Other countries/institutions have contacted us to contract our teams for future developments: METIS/COR Spin-off for commercial instruments ESA wants to use the technology for others applications (Earth Observing missions, tunable filters, etc )

31 Conclusions Spain has some of the key technologies for the development of spectropolarimeters thanks to a long-term strategy: from IMaX to SO/PHI. These technology and experience can be utilized in other applications than Solar Physics. These technologies for space instrumentation have been developed in house, at the participating institutes, thanks to the collaboration and excellence of scientific and engineering teams. A technological transfer should be desirable, but it should be pointed out that the Public Institutes have a fundamental task in the innovation due to inherent high risk component. Additionally, they are the key link between scientists and the industry, but basic and applied research and technological development should be carried out there. The SO/PHI team is worried by the future of this work, established on a longterm strategy and currently under question due to the funding problems.

32 Additional slides

33 Spanish organization chart

34 Spanish contribution Alemania 49% España 41% Noruega 1% Suecia 1% Francia 8%

35 Spanish contribution Alemania 49% España 41% Noruega 1% Suecia 1% Francia 8%