1. Partially Ionized Plasma Effect in Dynamic Solar Atmosphere Naoki Nakamura 2015/07/05 Solar Seminar

2. 200Mm Asai + (2003) Solar flare Chromospheric jets Hinode CaII H Solar Activity with Emerging flux 20 Mm

3. Solar chromosphere Hinode XRT Hinode SOT

4. Difficulty of observation of chromosphere PhotosphereChromosphereCorona observationContinuum +lineLineEUV line+ X-ray RadiationOptically thick?Optically thin Local thermodynamic equilibrium (LTE) Yes No Association with physical variables Source function is nearly equal to Planck function => Intensity is highly relates to local gas temperature Photospheric radiation field affect excitation states of atoms, which relates to line. => Intensity could not determined by local physical variables EM : is proportional to density squared Line intensity is highly depend on associate ionization degree, which relates to temperature It is difficult to estimate physical variables from chromosphere observation

5. Solar chromosphere Hinode XRT Hinode SOT

6. Chromosphere (partially ionized plasma) Emerging flux activity in solar atmosphere Current sheet Shibata et al. 2007 Corona (fully-ionized plasma) Photosphere (weakly ionized plasma) ・ What height and physics are important ? ・ Reconnection is same in all layer?

7. Plasma and magnetic field Magnetic field Lorentz Force （ gyration) - + Charged Particles Electric field Frozen in Plasma is frozen into magnetic field Plasma - +

8. Break of frozen in - + Plasma pass through field Non-ideal effect

9. Hall Effect Electron gyration Ion no gyration Magnetic field e p ex1:Difference of Larmor radius Ion Larmor radius > Characteristic scale>Electron Larmor radius P n n n ex2:Collisional frequency difference to neutrals (high density partially ionized plasma) Charged particle cannot gyrate if collisional frequency to neutral become large Ion collisional time<gyration time<electron collisional time Collision

10. Ambipolar diffusion n + - + ① ① Charged Particles <= Lorentz force ②neutral Particles <=Collision to charged particles =>momentum transfer ③ [Sufficient collision] neutrals seems to be frozen into magnetic field [Insufficient collision] neutrals are left =>Ambipolar diffusion Collision ② ③

11. Non-ideal effect to magnetic reconnection J Reconnection picture become difference by each effect

12. Solar atmosphere(VAL3c) gravitationally stratified atmosphere => What kind of effect is important for each height?

13. Khomenko et al. 2014 Compare non-ideal MHD effect in partially ionized plasma Left: quiet Sun Right: Sunspot umbra Non-ideal MHD effect in Solar atmosphere -atmospheric model (magnetic field)-

14. Non-ideal MHD effect in Solar atmosphere -atmospheric model (ionization fraction)- Khomenko et al. 2014 Compare non-ideal MHD effect in partially ionized plasma Left: quiet Sun Right: Sunspot umbra

15. Importance of each non-ideal effect Khomenko et al. 2014 [Quiet] Lower atmosphere : Ohmic and Hall  Higher atmosphere( >1000km) Ambipolar [Sunspot] Lower atmosphere: Hall  Higher atmosphere (>300 km) Ambipolar

16. Minimum magnetic structure by non-ideal effect (Quiet Sun) Time and spatial scale comparable to advection term

17. Minimum magnetic structure by non-ideal effect (Sunspot umbra) Time and spatial scale comparable to advection term

18. Discussion From bottom to upper atmosphere Reconnection picture change Sweet-Parker-like (photosphere) Petschek-like (lower chromosphere) Sweet-Parker-like (upper chromosphere) Quiet Sun ?

19. Dynamic atmosphere Solar Atmosphere is not static =>Dynamic Atmosphere! What is a effect of dynamic parameter change in active phenomena? Carlsson & Stein 1995 Temperature change on time

20. Leake & Arber 2006 Left : fully-ionized Right : partially-ionized Ambipolar diffusion effect life up magnetic field more Emerging flux in partially ionized plasma

21. Parameter change in emerging-flux Leake & Arber 2006 Thin Solid: fully ionized case, Dashed :with ambipolar diffusion Plasma parameter greatly change during emerging flux with ambipolar diffusion =>Dynamic atmosphere is necessary to understand chromopheric reconnection

22. Discussion (Dynamic atmosphere) Ambipolar diffusion approximation (single fluid description) assuming ・ plasma pressure and inertia is much less than ・ Local thermodynamic equilibrium (LTE) <=Both assumptions are bad at the top of chromosphere =>Two fluid description is necessary

23. Summary ・ Solar atmosphere is gravitationally stratified partially ionized plasma and dominant source of non-ideal effect is different with height Photosphere: Ohmic diffusion Lower chromosphere : Hall effect Upper chromosphere :ambipolar diffusion ・ Non-ideal effect to magnetic reconnection is difference in Hall and ambipolar effect ・ Non-static atmosphere, plasma parameters is much difference in static atmosphere. =>Full simulation is important to understand such a phenomena

24. Gravitational stratification

25. Two fluid stratification (no-magnetic field)

26. AFR atmosphere equilibrium

27. 2 fluid stratification