（image by NING Zhongjun）

Fig.1Total intensity maps of He II (a), O V (b), Si VII (c), Mg II (d), Fe XVI (e), and Doppler velocity map (f) of Fe XVI for one EIS raster. RHESSI X-ray contours are overplotted on the Fe XVI intensity map with the time-dependent source distribution at a given energy band of 6 – 9 keV, and Fe XVI velocity map with energy-dependent source distribution at a given time of 14:14:35 UT.

Prof. NING Zhongjun carried out a timely research on the Solar flare is one type of an eruption event occurrence in the solar corona. Based on the standard model, the plasma could be driven to flow upward from the chromosphere to corona to fill the flare loops during the solar flare, which is so-called “chromospheric evaporation”. In this paper, we explore the evidences of the chromospheric evaporation at the hard X-rays and EUV in an C1.1 flare occurred on 14 December 2007. Both Hinode/EIS and RHESSI observations are used. One of EIS rasters perfectly covers the double hard X-ray footpoints, where the EUV emission appears strong shifts from the cool line of He II (log T = 4.7) to the hot line of Fe XVI (log T = 6.4). 

According to evaporation model, the red shifts are expected at the chromospheric lines with a lower temperature, while the blue shifts are seen at the coronal hot lines for the flare kernels or footpoints. Data analysis shows such evidence from the Hinode/EIS EUV observations in this event. And the blue shifting velocity is a few hundreds km/s at Fe XVI (log T = 6.4). The mass motion with such order of velocity is possible to observe at the hard X-ray emission. Because the hard X-rays are produced by the thick-target model. The chromospheric evaporation drives the hard X-ray targets to move from the flare footpoint to loop top. Observationally, the hard X-ray emissions tend to rise up the double footpoint sources and finally merge into a single source around the loop top. With its full disk solar imaging capability, wide energy coverage (3-17,000keV), and high sensitivity, RHESSI provides unprecedented capabilities for investigating the X-ray source motion at different energy bands with a high temporal resolution after the chromospheric evaporation. In this paper, 　we analyze RHESSI X-ray images at 15 energy bands and a time cadence of 1 second around the hard X-ray peak at the 14 December 2007 solar flare. The results show a similar topology for the time-dependent source distribution (i.e. at 14:14:35 UT) as that for energy-dependent source distribution (i.e. at a given energy band of 6 – 9 keV) overlapped on EUV bright kernels. These facts are well consistent with the evaporation model seen at hard X-ray emissions. It is the first time to detect the chromospheric evaporation evidences at both EUV and hard X-ray .The work by NING Zhongjun (corresponding author),  CAO Wenda,  accepted by Solar Physics, has been published online http://www.springerlink.com/content/458p23m424575gn1/