1. Magnetic connection between the photosphere and the corona
S. Kamio
Solar Seminar

2. Introduction
Magnetic field must play an important role in the connection between photosphere and corona
may be related to surge, macro spicule, or EUV blinker?
Handy and Schrijver, 2001, ApJ, 547, 1100.
Schrijver and Title, 2003, ApJL, 597, 165.
De Pontieu et al., 2003, ApJL, 595, 63.

3. Observation Observation campaign in Aug 1997 Long period of 85hr
EIT/SOHO Fe XII 195Å (peak sensitivity at 1.6x106 K) FOV 660”x 660” (2.5” / pixel) cadence of 17 min
MDI/SOHO High resolution magnetogram FOV 620”x 387” (0.6” / pixel) cadence of 1 min
Handy and Schrijver (2001)

4. Data Processing
Raster: EIT, Contour: MDI
Remove diffuse haze in EIT data by high-pass filter  enhancing small scale structures
MDI images are averaged over 7 min

5. Emerging flux
Emerging flux larger than 1018Mx are associated with an EIT bright feature.
When footpoint separation reached about 14Mm, which is comparable to super-granule size, coronal loop reconnect to more distant flux concentrations.
14Mm (most frequent)

6. Reconnection
flux merging in the super-granular cell boundary (about 30hr)
In the course of the merging, positive flux reconnected to the negative flux of distant active region (110Mm apart).
30hr

7. Flux vs. separation
Correlation between footpoint separation and magnetic flux in the footpoint
Flux must exceed 3x1018Mx to appear bright in EIT image
EIT resolution limit

8. Flux vs. intensity
Correlation between magnetic flux in footpoint and integrated loop intensity
Extension of the relation between large scale field and 1MK corona (Schrijver 1990)

9. Spatial autocorrelation
Anisotropy in NS and EW
Isotropy
East-west
North-south
Anisotropy is due to large scale loops connecting active regions.
There is no preferred orientation of small scale loops

10. Lifetime
Lifetime is defined as the time when correlation amplitude drops to 1/e.
Nominally 14-20hr for quiet corona(1MK).

11. Field line (1) Potential field approximation
Field lines starting from 7Mm above the photosphere are displayed.
Classical network canopy model
Schrijver and Title (2003)

12. Field line (2)
Field line starting from network concentration of 3x1018Mx
In this case, a half of flux fall back to internetwork region.
Contribution of internetwork field is ignored in classical canopy model.

13. Intensity oscillation
Intensity oscillation in active region plage
Crosses mark the location of oscillation
Periods s
TRACE 171Å Hα(SVST)
De Pontieu et al.(2003)

14. Light curves
Light curves and wavelet power of oscillating points

15. Correlation
Significant correlation between upper chromosphere and transition region.
Less clear correlation between photosphere and transition region, delay of 150s
Propagating wave?

16. Template
Contents