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SOLIS: Status and results

SOLIS: Status and results. Alexei A. Pevtsov (National Solar Observatory, USA). SOLIS.

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SOLIS: Status and results

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  1. SOLIS: Status and results Alexei A. Pevtsov (National Solar Observatory, USA)

  2. SOLIS Synoptic Optical Long-term Investigations of the Sun (SOLIS) is a synoptic facility for solar observations over a long time frame that is funded by the National Science Foundation (NSF) and designed and built by the National Solar Observatory (NSO).

  3. SOLIS Instruments • SOLIS is composed of a single equatorial mount carrying three instruments: • the 50 cm Vector Spectromagnetograph (VSM), Fe I 6301-02, Ca II 8542, He I 10830 • the 14 cm Full-Disk Patrol (FDP), and • the 8 mm Integrated Sunlight Spectrometer (ISS). • In operation since 2003, plans for relocation and upgrades

  4. SOLIS/VSM The Vector Spectromagnetograph (VSM) is designed to obtain high- quality magnetic field observations in the photosphere and the chromosphere. V U Q I

  5. Magnetic fields rule!

  6. ISS Ca K and H line Parameters solis.nso.edu

  7. Long-term spectral irradiance SOLIS/ISS CaK Old Sac Peak CaK observations

  8. Recent Improvements • SOLIS/VSM full Stokes profiles are now inverted using VFISV (Very Fast Inversion) code developed by J.M. Borrero et al. (2009) for the Helioseismic and Magnetic Imager (HMI) on NASA's Solar Dynamics Observatory. • SOLIS synoptic maps are produced via same interface as GONG maps . • Synoptic maps of photospheric vector magnetic field (Carrington rotations CR2109-2131).

  9. photosphere chromosphere

  10. NISP/Atmosphere Highlights • Effect of uncertainties in synoptic maps on potential field extrapolation • Sun-as-a-star research (CaK basal profiles) • Vector field synoptic maps and helicity studies • Large-scale NLFFF modeling • Current/magnetic and kinetic helicity

  11. Effect of uncertainties in synoptic maps on potential field extrapolation

  12. CaK Basal Profiles (SOLIS/ISS) • Basal profiles represent non-magnetic chromosphere and thought to be independent of solar cycle • SOLIS/ISS data from Dec 2006 – July 2011 • Deconvolved quiet-Sun and active-Sun profiles and studied their cycle variation Pevtsov et al, 2013

  13. CaK Basal Profiles • Basal profiles originating from the non-magnetic chromosphere may vary slightly between the minimum and rising phase of the sunspot cycle. • This may indicate a possible change in properties of “mean” chromosphere with phase of the solar cycle. • For active-Sun profiles, we see a difference in amplitude between K2R and K2V, which may be related to dependency of flux of acoustic waves on the phase of solar cycle. Reference range “a” Reference range “b” Reference range “c” K3 of basal profile K3 in basal profile vary with solar cycle; three reference ranges (a-c) do not.

  14. Synoptic Vector Maps (SOLIS/VSM) Up-down • Weak photospheric fields systematically deviate from vertical direction • Hemispheric helicity rule is confirmed. • Helicity has opposite sign for strong and weak fields East-West North-South Gosain et al (2013)

  15. Synoptic Vector Maps in NLFFF Global Modeling (SOLIS/VSM) NLFFF global model EIT image Magnetic free energy photosphere • First ever use of synoptic vector maps for NLFFF extrapolation • Magnetic free energy can be used to characterize flare/CME potential of active regions. 80 Mm above photosphere Tadesse et al (2013)

  16. Helicity of subsurface flows and photospheric magnetic fields • Current helicity of photospheric field and kinetic helicity of subphotospheric flows have the same sign • In about 70% of all locations, kinetic helicity follows the hemispheric rule • Amplitude of kinetic helicity is larger in areas of sunspot activity • There is an indication of possible reversal in helicity rule for kinetic helicty early in Cycle 24 in low latitudes. Current helicity (SOLIS/VSM) Kinetic helicity (GONG) Komm et al, 2013

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