Evolution of H Flare Kernels and Energy Release
Ayumi ASAI
Nobeyama Solar Radio Observatory, NAOJ
6th Solar-B Science MeetingNovember 11, 2005 @Kyoto
2001-Apr-10 flare (Hida Obs.)
What can we learn from Flare Kernels/Ribbons?
magnetic reconnection(Carmichael 1964; Sturrock 1966; Hirayama 1974; Kopp-Pneuman 1976)
Evolution of flare ribbons Information on Magnetic reconnection
chromoshere
corona
What can we learn from Flare Kernels/Ribbons?
• Precipitation of accelerated particles into the chromosphere
HXR emissions and H kernels
Precipitation of nonthermal particles
HXR
bremsstrahlung rapid thermalization
H kernel
H kernels Information on particle acceleration
What kind of information, and how, we can derive from the Ha observations on flare ribbons and kernels?
simultaneously brighten
• 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
?
1. Conjugacy of H Footpoints
red:positive, blue:negative
Asai et al. 2003
Movement of the site of energy release
t
Focus on Each Pair
2. Energy Release Rate
• 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
AvB
dt
dEW in
c
42
2
Reconnection model indicatesAsai et al. 2004
microIIW HXR
Empirically, it is said that
Electric Field
fpinc vBvBE
Energy Release Rate
conservation of magnetic flux
Poynting Flux
fpinc vBvBW 22 I estimate the energy release rate, by using observable values (Bp, vf)
H flare ribbons
Bc
Bp
microwave
HXR
reconnection rate
Poynting flux
An HXR burst occurred on the slit (05:19 UT).
Reconnection Rate and Poynting Flux
B vB2 v
microwave
HXR
reconnection rate
Poynting flux
An HXR burst occurred on the slit (05:26 UT).
Reconnection Rate and Poynting Flux
H image
HXR sourcesflare ribbons
HXR/microwave Emission
Energy Release Rate
microIIW HXR
Quantitative Estimation
E4
E3
E1
W4
W3E2W2
W1 Comparison of Poynting and Electric Field (Reconnection Rate) between the H kernels with HXR sources and those without ones
E2W2
• H line is shifted red-ward red-asymmetry• velocity : 50-100 km/s
H
H spectrumIchimoto & Kurokawa 1984
flare
chromosphere
corona
compression
X-ray
H line
3. H Kernel Spectroscopy
Red-Asymmetry Map
2/)( bluered
bluered
II
II
map
2/)( bluered
bluered
II
II
• H +1.5A, -1.5A• we calculated
as an indicator of r.a.
• all over the flare ribbon, the tendency of r.a. is seen
Scatter Plot (intensity vs RA)in
tens
ity o
f H
ker
nel
redbluestrong asymmetry @outer edges of the flare ribbon2/)( bluered
bluered
II
II
The downflow velocity is roughly about 30 km/s.
Red Asymmetry
Summary
• We can learn from H 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!