DIFFERENT PATTERNS OF CHROMOSPHERIC EVAPORATION IN A FLARING REGION OBSERVED WITH HINODE/EIS

We investigate the chromospheric evaporation in the flare of 2007 January 16 using line profiles observed by the Exterme-UV Imaging Spectrometer on board Hinode. Three points at flare ribbons of different magnetic polarities are analyzed in detail. We find that the three points show different patterns of upflows and downflows in the impulsive phase of the flare. The spectral lines at the first point are mostly blueshifted, with the hotter lines showing a dominant blueshifted component over the stationary one. At the second point, however, only weak upflows are detected; instead, notable downflows appear at high temperatures (up to 2.5-5.0 MK). The third point is similar to the second one only in that it shows evidence of multi-component downflows. While the evaporated plasma falling back down as warm rain is a possible cause of the redshifts at the second and third points, the different patterns of chromospheric evaporation at the three points imply the existence of different heating mechanisms in the flaring active region.