1. Downflows and Plasmoid Ejections as a Reconnection Outflow
Ayumi ASAI
Kwasan Observatory, Kyoto University
collaborated with
H. Takasaki, T. Yokoyama, M. Shimojo, and K. Shibata
AOGS 1st Annual Meeting, July 7, 2004

2. What are Downflows?
downward motion was found above post-flare loops by Yohkoh SXT
velocity: 45–500 km/s
dark feature
often seen in the decay phase of LDEs
moving void?
new evidence of magnetic reconnection
McKenzie (2000)

3. TRACE Downflow TRACE has also found downflows above post-flare loops
spectroscopic analyses with SOHO/SUMER
flow of rarefied plasma?
we examine such TRACE downflow motions with higher spatial resolution
Innes et al. (2003)

4. What are Plasmoid Ejections?
X-ray plasmoids are oftern ejected, associated with solar flares
Ohyama & Shibata (1997)
they are accelerated during impulsive phase
we examine the features of downflows and plasmoid ejections, and discuss their relationship with magnetic reconnection
hight
HXR
time

5. Event (1): Downflows Flare 2002-July-23, 00:15UT GOES X4.8
NOAA 0039 (SE limb)
Movie
EUV (TRACE 195A)
This filter is sensitive to
1 MK and 10 MK plasma Ha
Asai et al. (2004)

6. Time Slice Image Time slice image downflow ascending velocity
~ 40 km/s
slit
super hot plasma (10MK)
TRACE 195A
post-flare loop (1MK)
~ 20 km/s
time

7. Velocity of Downflows downflow velocity: 100 – 250 km/s
Time slice image
TRACE 195A
slit A
slit A
slit B
downflow velocity:
100 – 250 km/s
~previous results
slit B

8. Time of Downflows
Time slice image
These TRACE downflows are seen not only in the decay phase but also in the impulsive phase and main phase
GOES
NoRH 17GHz
NoRH 34GHz
00:00
01:00
02:00

9. Timing of Downflows
Time slice image
TRACE 195A
slit A
slit A
slit B
The timings of the down flows correspond to microwave/HXR bursts.
slit B
RHESSI keV

10. Timing of Downflows
Time slice image
TRACE 195A
slit A
slit A
slit B
The timings of the down flows correspond to microwave/HXR bursts.
slit B
NoRH 17GHz

11. Event (2) : Plasmoid Ejections
Flare
2000-Nobember-24 14:50UT
GOES X4.8
NOAA 9236
Data
SXR…Yohkoh/SXT
Takasaki et al. (2004)

12. Multiple Plasmoid Ejections
Yohkoh/SXT
slit
multiple plasmoid ejections
each of them is ejected at the time corresponding to the HXR burst
plasmoid ejections play an important role in energy release process through magnetic reconnection
Takasaki et al. (2004)
Time slice image

13. Reconnection Outflow
plasmoid ejection
Plasmoids (magnetic islands) are formed in a current sheet and are ejected in both directions
upward ejection :
plasmoid ejections
downward ejection :
downflows
Tanuma & Shibata (2001)
downflows

14. Comparison plasmoid ejection downflow velocity 30-500 [km/s]
size (width)
1-10･104 [km]
2-10･103 [km]
density
1-10･109 [cm-3]
~109 [cm-3]
impulsive ph.
Yes
decay ph. No
HXR/m-wave

15. Summary
We studied the features of the TRACE downflows and X-ray plasmoid ejections
They show good correlations with HXR/microwave bursts
downflows are closely related to reconnection outflow
generation and ejection of plasmoid in the current sheet are important process in magnetic reconnection

16. What are Downflows…? propagation of reconnection outflows
Tandokoro & Fujimoto (2003)

17. What are Downflows…?
simulation
observation

18. July 7 … Tanabata !
The star festival: On this day two stars (Altair and Vega) that are usually separated from each other by the milky way, come together.
People hang papers with wishes written on it on a bamboo tree in the hope they become true.