Variations of the Plasma Environment Revealed by the Evolution of the Supra-arcade Fan in the 2017 September 10 Flare

Abstract Based on observations from the Interface Region Imaging Spectrograph and Hinode, we analyze thermodynamic evolution of supra-arcade fan (SAF) in 2017 September 10 flare. The SAF presents discontinuous characters during rising process, indicating a nonuniform process magnetic reconnection solar eruption. intensity peaks high-temperature spectral lines (Fe xxi 1354.08 Å, Fe xxiii 263.76 xxiv 255.10 Å) basically correspond to valley Doppler velocity width. temperature density increase spatially at upper boundary SAF. These results indicate that compressed interface may exist SAF, where plasma environment shows remarkable changes density, temperature, turbulence. In view fact height is close hard X-ray source, conclude could be related termination shocks (TSs), taking into account synthetic profiles obtained numerical experiments. turn, variations might useful tools for identifying TSs EUV observations.