1. Downflow as a Reconnection Outflow
Ayumi ASAI
Kwasan and Hida Observatories, Kyoto University
The 5th Solar-B Science Meeting Nov ,
Abstract
1. Introduction
Downflow
Yohkoh (SXT) has found downflows above postflare loops
McKenzie and Hudson 1999; McKenzie 2000
velocity: 45–500 km/s
dark feature
often seen in the decay phase of LDEs
Recently TRACE also has found the downflows above postflare loops Innes et al. 2003a; b
 We can examine such TRACE downflows with much higher spatial resolution than before.
We present a detailed examination about the evolution of TRACE downflows (sunward motions) seen above postflare loops. We also propose an observation of downflows by Solar-B.
downflows observed in the 2000 January 21 flare (Yohkoh/SXT)
2. Data
4. Observation of Downflows by Solar-B/EIS
NOAA 0039
Flare
2002-July-23 00:15UT
GOES X4.8
NOAA 0039 (Southeast limb)
Data
EUV…TRACE (195Å)
HXR...RHESSI
microwave…Nobeyama Radioheliograph
Emission Measure
1.  ~ a few×1027 cm-5
FOV & Cadence
near the solar limb,
104~105 km above a flare loop
 depends on the size of a flare
downflows
sun
flare
slit
full disk image (Ha) of the flare (Sartorius Telescope)
example of the observation
FOV
1 slit position (fixed)
red thick line
slit scan (red box)
~ 50 arcsec width
Cadence
5 second or less
~ 60 second
Time slice image
3. Results
slit A
TRACE 195A
Velocity
100 – 250 km/s
~previous results
Time
These TRACE downflows are seen not only in the decay phase but also in the impulsive phase and main phase
Timing
Down flows appear when microwave/HXR bursts occur.
slit A
Resolution
Size of downflows (> 2000 km; 3 arcsec) must be resolved.
Others
Co-observation with XRT is needed (to follow the features of high-temperature plasma region)
Downflows start to be seen 5~10 min after the beginning of a flare.
We can adjust the slit to the proper position just AFTER a flare occurs.
slit B
slit B
NoRH 17GHz
RHESSI keV
GOES flux
NoRH 17GHz
NoRH 34GHz
00:00
01:00
02:00
5. Summary
light curve of the flare
The downflows occurred when strong magnetic energy was released. These results show that they are correlated with the reconnection outflows.
We found that the downflows are seen not only in the decay phase but also in the impulsive and main phases of flares.
We also found that the times when the downflow motions are seen correspond to those of the bursts of nonthermal emissions in hard X-ray and microwave.
The downflows occurred when strong magnetic energy was released and that they are correlated with the reconnection outflows.
The observation of downflows with Solar-B may help to explain what the downflows are.
Temperature & Density
super-hot, low-density plasma…1
(Previous Woks with SXT, SUMER)
T: 0.8~2･107 [K]
n: ~109 [cm-3 ]
(supra-hot plasma …2)
T: >2･107 [K]
plasmoid ejection
downflows
model of the magnetic reconnection