Current sheet is believed to be the region of energy dissipation via magnetic reconnection in solar flares .
However , its properties , for example , the dynamic process , have not been fully understood .
Here we report a current sheet in a solar flare ( SOL2017-09-10T16:06 ) that was clearly observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory as well as the EUV Imaging Spectrometer on Hinode .
The high-resolution imaging and spectroscopic observations show that the current sheet is mainly visible in high temperature ( > 10 MK ) passbands , particularly in the Fe xxiv 192.03 Å line with a formation temperature of \sim 18 MK .
The hot Fe xxiv 192.03 Å line exhibits very large nonthermal velocities up to 200 km s ^ { -1 } in the current sheet , suggesting that turbulent motions exist there .
The largest turbulent velocity occurs at the edge of the current sheet , with some offset with the strongest line intensity .
At the central part of the current sheet , the turbulent velocity is negatively correlated with the line intensity .
From the line emission and turbulent features we obtain a thickness in the range of 7–11 Mm for the current sheet .
These results suggest that the current sheet has internal fine and dynamic structures that may help the magnetic reconnection within it proceeds efficiently .