Evolution of Ha Flare Kernels and Energy Release Ayumi ASAI Nobeyama Solar Radio Observatory, NAOJ 6th Solar-B Science Meeting November 11, 2005 @Kyoto 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.

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)

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?

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

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

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

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

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

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

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

Quantitative Estimation W1 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

3. Ha Kernel Spectroscopy Ichimoto & Kurokawa 1984 Ha spectrum Ha line is shifted red-ward red-asymmetry velocity : 50-100 km/s flare X-ray corona Ha compression chromosphere Ha line l

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

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

Red Asymmetry l

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

Thank you!