We performed coordinated observations of AR 12205 , which produced a C-class flare on 2014 November 11 , with the Interface Region Imaging Spectrograph ( IRIS ) and the Domeless Solar Telescope ( DST ) at Hida Observatory .
Using spectral data in the Si \emissiontype IV 1403 Å , C \emissiontype II 1335 Å , and Mg \emissiontype II h and k lines from IRIS and the Ca \emissiontype II K , Ca \emissiontype II 8542 Å , and H \alpha lines from DST , we investigated a moving flare kernel during the flare .
In the Mg \emissiontype II h line , the leading edge of the flare kernel showed the intensity enhancement in the blue wing , and the smaller intensity of the blue-side peak ( h2v ) than that of the red-side one ( h2r ) .
The blueshift lasted for 9–48 s with a typical speed of 10.1 \pm 2.6 km s ^ { -1 } and it was followed by the high intensity and the large redshift with a speed of up to 51 km s ^ { -1 } detected in the Mg \emissiontype II h line .
The large redshift was a common property for all six lines but the blueshift prior to it was found only in the Mg \emissiontype II lines .
A cloud modeling of the Mg \emissiontype II h line suggests that the blue wing enhancement with such peak difference can be caused by a chromospheric-temperature ( cool ) upflow .
We discuss a scenario in which an upflow of cool plasma is lifted up by expanding hot plasma owing to the deep penetration of non-thermal electrons into the chromosphere .
Furthermore , we found that the blueshift persisted without any subsequent redshift in the leading edge of the flare kernel during its decaying phase .
The cause of such long-lasting blueshift is also discussed .