1. Evolution of Ha Flare Kernels and Energy Release
Ayumi ASAI
Nobeyama Solar Radio Observatory, NAOJ
6th Solar-B Science Meeting
November 11,
First of all, I would like the SOCs and the LOCs for inviting me and their kind arrangements.
Today, I would like to present what can we learn from flare ribbon expansion.

2. What can we learn from Flare Kernels/Ribbons?
2001-Apr-10 flare (Hida Obs.)
Evolution of flare ribbons
 Information on Magnetic reconnection
magnetic reconnection
(Carmichael 1964; Sturrock 1966; Hirayama 1974; Kopp-Pneuman 1976)

3. What can we learn from Flare Kernels/Ribbons?
Precipitation of accelerated particles into the chromosphere
HXR emissions and Ha kernels
Precipitation of nonthermal particles
HXR
Ha kernel
corona
Ha kernels  Information on particle acceleration
　chromoshere
bremsstrahlung
rapid thermalization
What kind of information, and how, we can derive from the Ha observations on flare ribbons and kernels?

4. 1. Conjugacy of Ha Footpoints
Asai et al. 2003
Nonthermal particles and thermal conduction bombard the chromospheric plasma at both the footpoints simultaneously
The temporal evolutions of the footpoints are similar to each other
We identify the conjugated pairs of the footpoints which show similar light curves ? N S
simultaneously brighten
red:positive, blue:negative

5. Focus on Each Pair
Movement of the site of energy release t

6. 2. Energy Release Rate
Asai et al. 2004
Reconnection model indicates
estimate of the amount of the released energy, by using observable values to test the reconnection model
compare the derived energy release rate with HXR/microwave light curves
Empirically, it is said that

7. Energy Release Rate Electric Field  conservation of magnetic fluxBc
 conservation of
magnetic flux Bp
Poynting Flux
Ha flare ribbons
I estimate the energy release rate, by using observable values (Bp, vf)

8. Reconnection Rate and Poynting Flux
microwave
HXR
reconnection rate
An HXR burst occurred on
the slit (05:19 UT).
Poynting flux
B v
B2 v

9. Reconnection Rate and Poynting Flux
microwave
HXR
reconnection rate
An HXR burst occurred on
the slit (05:26 UT).
Poynting flux

10. HXR/microwave Emission
HXR sources
flare ribbons
Ha image
Energy Release Rate

11. Quantitative EstimationW1
Comparison of Poynting and Electric Field (Reconnection Rate) between the Ha kernels with HXR sources and those without ones E2 W2 E2 W2 E1 W3 E3 E4 W4

12. 3. Ha Kernel Spectroscopy
Ichimoto & Kurokawa 1984
Ha spectrum
Ha line is shifted red-ward
red-asymmetry
velocity : km/s
flare
X-ray
corona Ha
compression
chromosphere
Ha line l

13. Red-Asymmetry Map Ha +1.5A, -1.5A we calculated
　as an indicator of r.a.
all over the flare ribbon, the tendency of r.a. is seen
map

14. Scatter Plot (intensity vs RA)
intensity of Ha kernel
blue
red
strong edges of the flare ribbon
The downflow velocity is roughly about 30 km/s.

15. Red Asymmetry l

16. Summary We can learn from Ha flare kernels/ ribbons:
Site and timing of energy release by identifying conjugated footpoints
Energy release rate, by using the separation motions of two ribbons and the photospheric magnetic field strengths
Dynamics at the footpoints by the red-asymmetry distribution

17. Thank you!