Download Deriving the detailed structure of EBs using the narrowband

Deriving the detailed structure of EBs using
the narrowband universal tunable filter (UTF)
Yuri Kato1 and Satoshi Nozawa1 and Masaoki Hagino2 and Kenichi Otsuji2
Kiyoshi Ichimoto3 and Satoru Ueno3 and Goichi Kimura3
1
Ibaraki University, 2National Astronomical Observatory of Japan, 3Kyoto University
[email protected]
We report the result of observation on an Ellerman bomb (EB) that occurred near the sunspot of
NOAA12356 in 2015 early June using Ha imaging system of Domeless Solar Telescope (DST) in
Hida observatory, Kyoto University.
EBs are small explosion phenomena that occur in the lower chromosphere. The spectral profile of
EBs has a characteristic structure of an absorption core at the Ha line center and asymmetric wide
emissions in both red and blue wings. EBs generally occur in emerging flux regions, beneath
expanding arch filament systems, at the ends of chromospheric fibrils forming superpenumbra, and
those are occasionally associated with small surges. So far, we performed several observations of EBs
using the horizontal spectrograph of DST. From the obtained data we derived the light curve and the
Doppler shift of core and wing components. As the result, it is conformed that the sporadic
brightenings are associated with upward motion and EBs occur in the lower chromosphere.
In this observation, we set the narrowband universal tunable filter (UTF) which was developed in
Hida observatory to acquire the slit-jaw image of the DST and observed 21 wavelengths by 0.2A step
from the Ha line center in order to investigate the light curves of EBs within the different
chromospheric layers. Herewith, deriving the detailed structure of EBs along the vertical direction
against the solar surface, we will explain the mechanism of energy release, the propagation in the
magnetic reconnection, and the heating of upper chromosphere.