Micro-Flare and High-Speed Down-Flow observed with VTT

1
Micro-Flare and High-Speed Down-Flow observed
with VTT
R. Kano(1), Y. Katsukawa(1), Y. Kitakoshi(2), T.
Shimizu(3), S. Tsuneta(1) and V. Martinez
Pillet(4)
(1) National Astronomical Observatory of Japan,
(2) Institute of Space and Astronautical Science
(3) University of Tokyo, (4) Instituto de
Astrofísica de Canarias
4. Photospheric Line Si 10827A
1. Abstract
It took 100 steps and 20 min for VTT to scan the
width of 30 arcsec. After the B5.4 flare, VTT
stared the scan from the south-east edge at
1317UT, and then the slit position moved to the
nourth-west edge (See Figure 4a). At this time,
two pores with opposite polarity were located at
the north of proceeding spot in NOAA 10789. There
was no significant velocity field at the
photosphere.
In this July, we took the observation time for
solar telescopes (VTT, SST and DOT) in Canary
islands, and carried out the campaign observation
with TRACE and SoHO satellites. On July 9, around
the proceeding spot in NOAA 10789 many transient
brightenings appeared in EIT images. We
continuously observed this spot with
spectropolarimeters in Vacuum Tower Telescope
(VTT), and made a movie of spectrogram. VTT has
two spectropolarimeters, POLIS and TIP2. We
observed Fe-6302/6303A with POLIS, and Si-10827A
and He-10830A with TIP2. At 1314UT, a B5.4 flare
occurred in the field-of-view. There is a small
brightening in EIT image, and small activities in
H-alpha images taken with SST. In He-10830A map
taken with VTT, high speed (about 20km/s)
down-flow transiently appeared near the magnetic
neutral line. It is associated with coronal
activity of the micro-flare. It seems to be a
down-flow in the chromospheric evaporation
process. In future, we will derive the vector
magnetic fields not only at the photosphere by
Si-10827A but also at the chromoshere by
He-10830A.
2. Data
On July 9, we took the following data set for the
analysis around the preceeding spot in NOAA
10789. At 1314UT a B5.4 flare occurred in the
VTT field-of-view (See Figure 1). Here we show
the results from VTT TIP data and EIT 195A data.
(a)
(b)
(c)
Table1 Data set for the proceeding spot in
NOAA10789
Figure4 Si 10827A data. (a) Off line intensity
of Si10827A, (b) Dopplergram from I-profile and
(c) Magnetgram from V-profile. The black lines
are the contours of the TIP continuum image. The
red and blue lines are the contours of
Dopplergram of He 10830A.
Site Inst. Wavelength Observation Time(UT) and Interval

VTT TIP Si10827/He10830 1044 1723, about 20 min interval
VTT POLIS Fe6302/6303 1044 1723, about 20 min interval
STT SOUP Ha-center/wing 1150 1800, about 15 sec interval
DOT No observation due to bad seeing
SoHO EIT 195 171/283/302 1000 1800, about 15 min interval 1 set taken around 1300
SoHO CDS No data due to observing a different target (10786)
TRACE TRACE No data due to observing a different target (10786)
5. Chromospheric Line He 10830A
Figure 6 clearly shows that there were no
significant motion at the photosphere, and that
there were high-speed down-flow (up to 20 km/s)
with/without the rest component. Region-C is
located in the opposite polarity with Region-A
and B. EIT bright boby might be a loop
connecting them.
(a)
(b)
(c)
Figure5 He 10830A data. (a) Line center
intensity, (b) Dopplergram from I-profile and (c)
Magnetgram from V-profile. A, B and C show
the regions with high-speed down-flows.
Region A
Region B
Region C
Figure1 GOES plot for July 09, 2005. Data
coverage of VTT, STT and EIT is shown.
3. Results from EIT data
3. Discussion
Region A
Region B
Region C
V
V
V
I
I
I
17km/s
20km/s
15km/s
Figure6 I-profiles (solid) and V-profiles (dash)
in the regions A, B and C.
(b)
(c)
(a)
6. Summary and Future Work
Table2 Properties of Region with High-Speed
Down-Flow
Figure2 EIT 195A image just after the B5.4
flare. (a) All of the image, (b) zoom-up around
NOAA 10789, and (c) the target of VTT. The black
lines are the contours of the TIP continuum
image. The red and blue lines are the contours of
Dopplergram of He 10830A. The regions of
down-flow of He10830A, A, B C, are
located the edge of an EIT bright body.
Item Value

Velocity of Si10827 No significant motion
Velocity of He10830 15 20 km/s downward with/without rest component.
Life Time ltlt 40 min
Spatial Size 1 5 arcsec
Spatial Location Around the edge of EIT bright body (loop footpoits?)
It is probably the down-flow associated the
chromospheric evaporation, which is simulated by
Fisher et al (1985, ApJ), and already observed by
Teriaca et al. (2003, ApJ). However, we have full
set of IQUV-profiles for both Si-10827A and He
10830A. In future, we will derive the
photospheric and chromospheric vector magnetic
field, and study the connectivity between the
magnetic activities and the coronal activities.
(b)
(a)
Figure3 Time evolution of EIT structure around
VTT field-of-view. (a) Intensity change of two
regions. It is clear that the B5.4 flare at
1314UT occurred in VTT-FOV.