1. Probing Coronal Magnetism with Multi-wavelength Polarimetry Silvano Fineschi INAF-Torino Astrophysical Observatory, Italy 25 May, 2013, Bern (CH)

2. Coronal Magnetism

3. B & resonance scattering from anisotropic source UV (permitted) lines: B los ;  los VIR (forbidden) lines:  pos Scattering and Superradial Doppler-dimming effect UV lines: Effect of B on ions v (i.e., kinetic T  & T // )

4. Beta 1.05 Ro 10 Ro 2 Ro Temp. minimum (photospheric field range: 100-2500 G) Photospheric VIR lines CIV 150 nm MgII h & k 280 nm HI Lyman series, OVI 103.2 nm & Fe IR lines G.A.Gary. 2001 HI Ly-  122 nm

5. Hanle Effect (tutorial)  Larmour  A  P is // or  B If  Larmour >> A (VIR forbidden lines) incident light

6. What is the Hanle effect sensitivity of coronal UV lines to magnetic fields? How many photons are needed to detect the Hanle effect in UV coronal lines?

7. A [10 7 s -1 ] ~ 0.88  g J  B [G] Hanle effect Sensitivity A FeXIII = 14 Hz  B Hanle  0.2-2  G A FeXIII << B corona (“saturated” Hanle effect)

8. Fineschi, van Ballegooijen & Kohl, 1999 HI Lyman , 97.2 nm

9. LOS contribution to the Stokes parameters Fineschi, 1993

10. (Min. Detectable Rot. Angle)  ~  P/P  PP P  P (Min. detectable Polariz.) ~ 1/signal-to-noise ratio P ~ P 0 /(1+Coll/Rad)  [rad] ~ 0.88  g J  B/A

11. OVI 103.2 nm HI Ly-  121.6 nm HI Ly-  103.2 nm HI Ly-  97.2 nm Coronal UV Lines Sensitivities to B

12. Resonance-scattering Polarization

13. 13 OVI 103.7 nm Doppler-dimming; CII pumping (S. Giordano courtesy) Coronal Lines Doppler-dimming

14. Super-radial Doppler-dimming Effect on Resonance Polarization Sahal-Brechot, 1992, 1998

15. UVCS results: solar minimum (1996-1997 ) On-disk profiles: T = 1–3 million K Off-limb profiles: T > 200 million K ! The fastest solar wind flow is expected to come from dim “coronal holes.” In June 1996, the first measurements of heavy ion (e.g., O +5 ) line emission in the extended corona revealed surprisingly wide line profiles...

16. The impact of UVCS Discoveries UVCS has led to new views of the collisionless nature of solar wind acceleration. Key results include: The fast solar wind becomes supersonic much closer to the Sun (~2 R s ) than previously believed. In coronal holes, heavy ions (e.g., O +5 ) both flow faster and are heated hundreds of times (250 MK) more strongly than protons (3 MK) and electrons (1 MK), and have anisotropic temperatures. (e.g., Kohl et al. 1997,1998)

17. Anisotropic temperatures from Ion-cyclotron resonance between Alfven waves and Larmor gyrations of ions +

18. Super-radial Anisotropic Resonance Polarization Fineschi (2001) Raouafi & Solanki (2002)

19. Anisotropic Super-radial Doppler-dimming effect Fineschi (2001) Raouafi & Solanki (2002)

20. 20 Source of the Solar Wind Habbal, Fineschi, et al. ApJ (1997)

21. Anisotropic Super-radial Doppler-dimming effect (OVI 103.2 nm line) Kahn (2012)

22. B & wind speed  0 Solar wind effects on UV Polarization B & wind speed = 0 Khan, Fineschi et al., 2011

23. HI Ly-  Khan (2012)

24. Anisotropic Super-rad Doppler-dimming effect Integration along LOS 2 different electron density models (Cranmer ApJ 2008)

25. HI Ly-  HI Ly-  HI Ly-  Khan, Degl’Innocenti, Fineschi et al. (2011) Effects on Polarization of B, Anisotropic Distributions, Active Regions,

26. (Min. Detectable Rot. Angle)  ~  P/P SNR ~ (P   ) -1 What does it take to measure it?  ~ 5  ~ 10 -1 rad P ~ 10 -1  SNR ~ 10 2

27. UV Spectro-polarimetry Polarimetry UV coronal lines Spectroscopy UV coronal lines + Coronal B effects on plasma (coronal heating mechanisms, solar wind acceleration) Coronal B (B los ;  los ) Hanle effect Coronal plasma parms (N ion, w, T //, T  ) Doppler-dimming -shift, -width Super-radial Doppler -dimming effect

28. SUMER Measurement of Hanle and ASD effects? P=(9  2)%;  = 9  6  Helioctr. Dist. = 1.3 R Wind speed w  40 km/s (Raouafi,1999) Hanle effect: B > 10 G;  B 50 km/s SR Doppler-dim.: B 30  ; w > 50 km/s Anisotr. SR Doppler-dim.: B <<1 G;  B  20  ; w  40 km/s (Fineschi, 2001; Raouafi, 2002; Khan, 2012)

29. SolmeX – COMPASS (ESA M-mission) Peter, et al. Exp. Astron. 2011

30. Coronal UV Spectro-Polarimeter (CUPS)

31. Moses, et al. SPIE 2011 Non-Formation Flying CUPS Telescope externally occulted with multi-stacked apertures

32. The CorMag was operated during the total solar eclipse of July, 11th 2010 on Tatakoto Atoll (French Polynesia) INAF-CorMag – 2010 Eclipse 32

33. UV Spectro-polarimetry Polarimetry UV coronal lines Spectroscopy UV coronal lines + Coronal B effects on plasma (coronal heating mechanisms, solar wind acceleration) Coronal B (B los ;  los ) Hanle effect Coronal plasma parms (N ion, w, T //, T  ) Doppler-dimming -shift, -width Super-radial Doppler -dimming effect