Strongly Blueshifted Phenomena Observed with {\it Hinode}/EIS in the   2006 December 13 Solar Flare
  We present a detailed examination of strongly blueshifted emission lines observed with the EUV Imaging Spectrometer on board the {\it Hinode} satellite. We found two kinds of blueshifted phenomenon associated with the X3.4 flare that occurred on 2006 December 13. One was related to a plasmoid ejection seen in soft X-rays. It was very bright in all the lines used for the observations. The other was associated with the faint arc-shaped ejection seen in soft X-rays. The soft X-ray ejection is thought to be an MHD fast-mode shock wave. This is therefore the first spectroscopic observation of an MHD fast-mode shock wave associated with a flare. 
Ayumi Asai, Hirohisa Hara, Tetsuya Watanabe, Shinsuke Imada, Taro   Sakao, Noriyuki Narukage, J. L. Culhane, and G. A. Doschek