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The Dynamic Chromosphere

The Dynamic Chromosphere. Mats Carlsson Institute of Theoretical Astrophysics, University of Oslo JAXA, November 20 2008. Semi-empirical model. VAL3C. Ca II H-line intensity. 1D NLTE hydrodynamic modelling. SUMER observations. Carlsson, Judge, Wilhelm 1997. Ca H timeseries from Hinode.

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The Dynamic Chromosphere

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  1. The Dynamic Chromosphere Mats Carlsson Institute of Theoretical Astrophysics, University of Oslo JAXA, November 20 2008

  2. Semi-empirical model VAL3C

  3. Ca II H-line intensity

  4. 1D NLTE hydrodynamic modelling

  5. SUMER observations Carlsson, Judge, Wilhelm 1997

  6. Ca H timeseries from Hinode

  7. Broad band filter contains too much photospheric signal for chromospheric diagnostics on-disk

  8. 3D models from convection zone to corona Hansteen 2004, Hansteen, Carlsson, Gudiksen 2007, Sykora, Hansteen, Carlsson 2008 • 16x8x16 Mm (2 Mm below, 14 Mm above z=0) • Open boundaries • Detailed radiative transfer along 48 rays • Multi-group opacities (4 bins) with scattering • NLTE radiative losses in chromosphere (CaII, H) • Optically thin losses in corona • Conduction along field-lines • Various initial magnetic field configurations • No imposed driving (selfconsistent convection)

  9. Ca H timeseries from Hinode

  10. Ca-H timeseries from model

  11. Red field lines Coloring is temperature (red=chromosphere green/blue= TR) Carlsson & Hansteen

  12. Heating of the middle chromosphere

  13. Chromosphere highly dynamic and filamentary • Hot and cool gas coexist • Non-magnetic chromosphere may be wholly dynamic • Magnetic fields crucial for the understanding of chromospheric heating, dynamics and connection with upper layers • Network chromosphere and internetwork mid-upper chromosphere magnetically heated • Whole zoo of wavemodes

  14. Ca emission at the limb

  15. What can be done from the ground? • Limb: scattering in atmosphere, difficult with adaptive optics • Spectroscopy: Image restorations difficult • Fabry-Perot: Hα, CaII 8542, photosphere Examples taken from Oslo-group observations at the Swedish 1m Solar Telescope (SST) on La Palma

  16. Hα blue wing at SST, Aug 10, 2007

  17. Spectroscopy SST: CaII 866.2 Red Blue

  18. Fabry-Perot • Swedish 1m Solar Telescope on La Palma • CRISP • Ca II 854.2 nm, spectral resolution 90 mÅ • 29 line positions -1900 mÅ to +1900 mÅ, step 100-200 mÅ, 11s cadence (full scan) • 24 line positions -900 mÅ to +190 mÅ, step 50 mÅ, 9s cadence (full scan), 33 min timeseries • diffraction limited (0.21”) (after MOMFBD restoration), 0.071”/pixel, FOV 66”x67” • June 13-15 2008

  19. Hα observations with SST • June 15th 2008 • CRISP Fabry-Perot • 25 line positions -1800mÅ to +800mÅ, step 100mÅ, spectral resolution 60mÅ • 6.7s cadence (full scan), 30 minutes timeseries • diffraction limited (0.16”), 0.071”/pixel, FOV 66”x67”

  20. Hα line center

  21. -800 mÅ

  22. +800 mÅ

  23. Why space? • UV gives much better diagnostics for the chromosphere (91.2-152 nm, Mg II 280 nm) • spectroscopy • observing across β=1 • coupling to transition region-corona • consistent time-series of any target

  24. What do we need? • UV • High spatial and temporal resolution • 0.2”, 1-10s • Spectroscopic capability • line shapes, 1 km/s • Polarimetry • 3D radiation-MHD combined with 3D NLTE modelling • 20 km resolution: 10243 : 4 months on 1000 cores

  25. Conclusions • Chromosphere is very dynamic and structured with small scales • Absolutely essential to have diagnostics from chromospheric plasmas together with higher temperature plasmas • Need 3D radiation-MHD modelling • Need mission like Solar-C plan B

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