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Evolution of Magnetic Features Observed Using Spectropolarimetry with IBIS

Explore the advancements in imaging spectropolarimetry of magnetic features using IBIS, including data calibration, analysis of polarization, and wave propagation in magnetized plasma. Discover new analysis tools and unresolved problems in astrophysics.

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Evolution of Magnetic Features Observed Using Spectropolarimetry with IBIS

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  1. Imaging Spectropolarimetry with IBIS: evolution of a magnetic feature. Del Moro D. Berrilli F., Egidi A., Viticchiè B., Stangalini M., Giannattasio F., Vantaggiato M. and the IBIS Team 6 Maggio 2009 Pisa – SAIt 2009

  2. Outline - Spectropolarimetry of Magnetic Features - IBIS a) Vector polarimetry upgrade b) Dual-beam polarimetry - Observations a)AR 11005 b) Dataset c) Data calibration & restoring - Data Analysis a) Total linear and Total circular polarization c) 3 and 5 minutes waves maps d) Correlation between 3min and Linear Polarization - Conclusions

  3. 2D Spectropolarimetry of Magnetic Features Many related unresolved problems: - Monolithic vs “Spaghetti” model Study of umbral dots and Light Bridges - Energy Storage a)Moat Flow b) Moving Magnetic Features - Wave propagation in Magnetized Plasma a)Magnetic Portals b) Magneto-Acoustic Waves

  4. IBIS Interferometric Bidimensional Spectrometer In spectropolarimetric mode, the incoming light to IBIS is modulated by a pair of liquid crystal variable retarders placed in a collimated beam upfront the field stop of the instrument. The light is analyzed by a beam splitter in front of the detector, imaging two orthogonal states onto the same chip thus allowing for dual-beam spectropolarimetry. The modulation is in such a way that at each wavelength position six modulation states I + S (and its orthogonal states I − S) are detected with the following temporal scheme: S = [+Q, +V, -Q, −V, -U, +U].

  5. Observations on October 15, 2008 from 16:34 UT to 17:43 UT NOOA 11005 [25.2N, 10.0W]

  6. Dataset Every 52 s: 147 Broad-band images 147 G-band images 21 point Full-Stokes scan of Fe I 617.3 nm 21 point I-only scan of Ca II 854.2 nm

  7. Data reduction and restoring MFBD for Broad-band images MFBD for G-band images Spectropolarimetric calibration + de-stretching for Full-Stokes scans of Fe I 617.3 nm Spectral calibration + de-stretching for I-only scans of Ca II 854.2 nm

  8. Data Analysis Magnetic Field Vector retrieval Total Linear polarization Circular polarization Magnetic field polarity

  9. Data Analysis 3 and 5 minute waves maps From correlation of Fe I Dopplergrams vs Ca II Dopplergrams

  10. Data Analysis Correlation between 3 minutes and linear polarization Candidate sites for fast magneto-acoustic wave propagation

  11. Conclusions - The spectropolarimetry of Magnetic Features with high time cadence offers new analysis tools to the astrophysics - Some of the results have been already submitted - A new promising dataset is ready for analysis References Brickhouse & Labonte 1988 SoPh, 115: 43 Jefferies et al. 2006 ESA-SP, 624: 16 Louis et al. 2008 SoPh, 252: 43 Rosenthal et al. 2002 ApJ, 564: 508 Solanki & Stenflo 1985 A&A, 148: 123 Tritschler et al. 2004 A&A, 415: 717 Viticchiè et al. 2009 ApJL, submitted Watanabe et al. 2008 PASJ, accepted

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