Simultaneous imaging and spectroscopic observation of high temperature cusp loops and bi-directional inflow in the solar flare

We succeeded in the simultaneous observation of high temperature cusp loops and bi-directional inflow of a solar flare. Solar flares are huge explosion in the solar corona. The standard model of solar flares based on the magnetic reconnection includes bi-directional inflow toward the reconnection point. Corresponding to the bi-directional inflow, high temperature loops like a cusp shape are formed due to the the magnetic reconnection. SOD/AIA is an EUV imaging telescope and has a great spatial and temporal resolution. On the other hand, it is difficult to know the temperature from the imaging data only because it includes emission from different lines. Therefore simultaneous spectroscopic observation is important. Hinode/EIS is an EUV spectrometer and useful for the spectroscopy of the plasma. We analyzed imaging data with SDO/AIA and spectroscopic data with Hinode/EIS of a C-class flare that occurred in 2012 beyond the solar limb. As a result, bi-directional inflow are observed with the images of 171A filter (around 1MK). At the same time, cusp loops are observed with the raster scans of FeXXIV emission line (over 10 MK) at the region surrounded by the bi-directional inflow. Cusp loops are also observed with high temperature filter 131A (over 10 MK). 131A filter also includes cool temperature emissions (logT ~ 5.6), however the results of the simultaneous spectroscopic observation of FeXXIV supports that these cusp loops have high temperature over 10MK. This is clear evidence that 1MK loops are heated over 10MK by the magnetic reconnection. Additionally, a strong blueshift over 300km/s is observed with FeXXIV as a Doppler shift at the region of the current sheet. This speed might reach Alfv'en speed considering the angle of the loop, which also supports the magnetic reconnection. These results indeed support the standard model and this is the first simultaneous observation of bi-directional inflow with imaging and cusp loops with spectroscopy as long as we know.