2. Solar Physic & upper-Atmosphere Research Group AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Atmospheric seismology with SDO: theory viewpoint R. Erdélyi & B. De Pontieu 1 robertus@sheffield.ac.uk, 2 bdp@lmsal.com 1 SPARG, Department of Applied Mathematics, The University of Sheffield (UK); LMSAL, Palo Alto (USA) http://www.shef.ac.uk/~robertus

3. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Recap… Two basic facts: Photosphere – chromosphere – TR – corona are magnetically coupled. Very highly structured and dynamic Magnetic field 5000 K UV 1600 Å 8000 K Hα 15,000K He EUV 50,000 K Fe VIII/IX EUV 1 MK Fe XI 1.5 MK Fe XIV 3 MK X rays 4-6 MK Credit: www.lmsal/com

4. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Recap… Two basic facts: Photosphere – chromosphere – TR – corona are magnetically coupled. Very highly structured and dynamic Is this environment not too hostile doing atmospheric/coronal seismology (A/CS)? Yes, it is!

5. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Recap… Two basic facts: Photosphere – chromosphere – TR – corona are magnetically coupled. Very highly structured and dynamic Is this environment not too hostile doing atmospheric/coronal seismology (A/CS)? Yes, it is! So, can we actually do A/CS? Not really! At least not in the strict sense of definition of seismology, but…

6. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield A few basic Q’s as far as AIA/SDO is concerned: What is needed to get the full potential of AIA out for A/CS? What do we not understand yet? Where are the stumbling blocks to get full seismological data about the corona? What kinds of tools need to be developed? What kind of software? Some fundamental Q’s…

7. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Solar interior Global oscillations p/f/g-modes Unifying feature of variety of solar atmospheric oscillations Waveguide concept MHD description Solar atmosphere More local oscillations Sunspot oscillations, prominence oscillations, coronal loop oscillations, plume oscillations Moreton & EIT waves Oscillations ubiquitous in Sun Objects: atmospheric oscillations

8. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Solar interior One resonator Numerous modes However, good news for atmosphere Standing + progressive waves Solar atmosphere Numerous resonators Practically 1-2 modes Oscillations ubiquitous in Sun Objects: atmospheric oscillations

9. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Low atmosphere Ph, Ch, possibly TR Isolated flux tubes Effect of stratification Stratification leads to the Klein-Gordon effect Higher atmosphere TR, Corona Magnetic environment vAvA vAvA (Roberts 1981, Rae & Roberts 1982, Erdélyi(2005) Another difficulty: different types of waveguides Atmospheric oscillations (Review: Erdélyi, Roberts, Ruderman, Thompson 2006; Erdélyi 2006)

10. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Seismic scales and elements ¤ Magnetic fields ¤ Flow fields Waveguides in solar atmosphere: Organised flows (steady loops) Random flows (energy bursts- driven flows: RA, MRC) Coherent fields (loops, arcades) Random fields (threads, fine struct’s)

11. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Joint AIA-MHI seismology ¤ Magnetic fields ¤ Flow fields Manifestations of presence of solar atmosphere: Organised flows (meridional; differential rotation, etc.) Random flows (granulation, convection, etc.) Coherent global fields (e.g. canopy) Random fields (magnetic carpet)

12. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Two examples Manifestation of coupling has some exciting & promising aspects: Influence of magnetic atmosphere, e.g. magnetic carpet, on oscillations. Role of photospheric motions (e.g. p modes) in the dynamics of the solar atmosphere!

13. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Example 1: line-widths (GONG) Surface gravity (f) modes Acoustic (p) modes Dziembowski and Goode, ApJ 2005

14. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Ex 1: Simple-minded modelling corona chromospheric transitional layer (L) photosphere x z y g solar interior B(z) canopy (h)

15. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Ex 1: Eigenmodes (L  0, B  0)

16. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield ¤ Three-layer model ¤ Polytrop interior ¤ Magnetic transitional layer  resonances  damping ¤ Isothermal magnetic upper atmosphere ¤ Presence of Alvén/slow continua ¤Tirry et al. 1998, Pintér et al. 1999 Ex 1: Eigenmodes (L  0, B  0)

17. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield ¤ Erdélyi and Pintér 2005 l = 100 L = 2 Mm Δν (μHz) B c (G) p3p3 p8p8 p4p4 f p1p1 p2p2 l = 100 L = 2 Mm Im ν (nHz) Ex 1: Eigenmodes (L  0, B  0)

18. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield ¤ Erdélyi, Pintér & Goossens 2006 Ex 1: Eigenmodes (L  0, B  0) Direction of B

19. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Modelling improvement Gabriel (1976), Phil. Trans. A281, 339 Dowdy et al. (1986) Solar Phys., 105, 35

20. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Possible challenges… ¤ De Pontieu, Tarbell & Erdélyi 2003

21. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Ex 2a: The Klein-Gordon waves Stratified atmosphere (g=const) Webb & Roberts, Sol. Phys, 56, 5 (1978) Ulmschneider and co’s, many papers in A&A Erdélyi & Hargreaves (2006) Equilibrium: Scale height: 1D, sound waves: Introduce Reviews by Roberts (2003), Erdélyi (2006) Progressive atmospheric waves

22. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Erdélyi & James (2004); De Pontieu et al. (2004) Leakage of photospheric motion into LA Sound, slow, Alfvén waves γ=5/3  1 Non-adiabatic plasma Inclination of magnetic wave guides Isothermal atmosphere Photosphere: ν ac = 4.8 mHz  P = 210 s (acoustic cut-off frequency) Corona: ν ac = 0.18 mHz  P = 91.7 min AIA: 2-10 s resolution => Theory needed Non-equilibrium MHD simulations 2-3D MHD Ex 2a: The Klein-Gordon waves

23. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Theory also needs to address Dissipative effects Twisted tubes Tube fine structure Closed tubes  standing waves Ex 2a: The Klein-Gordon waves AIA’s 2-10 s time resolution Not just sound/slow but Alfvén modes to be considered AIA’s wide temperature coverage Allows tracing from 0.8 MK to few MK

24. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Leakage of photospheric motions into the solar atmosphere: driving atmospheric dynamics (spicules and coronal waves) Example 2b:

25. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Ex 2b: Dynamics - Solar spicules Earth Peter & von der Lühe (1999)

26. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Not steady waves but wave trains of finite duration. Oscillations usually last for 32±7 mins or 3 to 7 cycles (just like p-modes): rarely continue for more than 40 min. Ex 2b: LA moss oscillations Oscillations usually suddenly start and stop.

27. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Ex 2b: P-mode driven spicules (and coronal oscillations) Vertical flux tube Inclined flux tube (50°) Chromospheric dynamics in inclined flux tubes are dominated by five minute periods because of significantly increased leakage of photospheric p-modes into the atmosphere

28. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield  = 50° The match between predicted spicule occurrence and observed spicule occurrence is good, especially considering the limitations of the numerical model Ex 2b: P-mode driven spicules (and coronal oscillations)

29. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Two types of observed oscillations can be distinguished 1.Propagating waves (Ofman et al. 1997, DeForest & Gurman 1998, Berghmans & Clette 1999, De Moortel et al. 2000, 2002a,b,c, Robbrecht et al. 2001, King et al. 2003, Marsh et al. 2003) 2.Standing waves SOHO/TRACE examples (mainly TR and higher) i) Standing kink-mode oscillations by TRACE (Aschwanden et al. 1999, 2002, Nakariakov et al. 1999, Schrijver & Brown 2000, Schrijver et al. 2002, ) ii) Standing slow-mode oscillations by SOHO/SUMER (Kliem et al. 2002; Wang et al. 2002, 2003a,b) Reviews by Aschwanden (2003), Wang (2004) Atmospheric oscillations

30. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Ex 2b: P-mode driven (spicules) and coronal oscillations Many observations of intensity oscillations in TRACE 171 Å loops, identified as propagating MAW in 1 MK plasma. TRACE 171 Å From De Moortel et al. (2002)

31. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Ex 2b: P-mode driven (spicules) and coronal oscillations Wavelet power for observations Intensity oscillations from observations Wavelet power for simulations rebinned to emulate resolution of data (30 s, 2 arcsec) Intensity oscillations from simulations (rebinned to emulate resolution of data)

32. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield P-mode driven spicules: 2-D

33. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Numerous examples of waves & osc’s in solar atmosphere structures MHD theory: satisfactory description, but improvements are badly needed (fine structures, radiation issues) Atmospheric seismology provides us information about: magnetic field, transport coefficients, fine structures, etc. Joint AIA-HMI seismology: e.g. photospheric motions (p-modes, granular, etc.) leak to atmosphere & atmosphere has back-reaction on global oscillations Stratification needs to be addressed in theory Summary

34. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield The end

35. Solar Physic & upper-Atmosphere Research Group Robert Erdélyi http://www.shef.ac.uk/~robertus AIA HMI Team Meeting 13-17 February 2006 University of Sheffield Summary ¤ De Pontieu, Tarbell & Erdélyi, ApJ, 590, 502 (2003)