Strongly Blueshifted Phenomena Observed with {\it Hinode}/EIS in the 2006 December 13 Solar Flare

TL;DR

This paper reports the first spectroscopic observation of an MHD fast-mode shock wave during a solar flare, using Hinode/EIS to analyze strongly blueshifted emission lines linked to plasmoid ejections.

Contribution

It provides detailed spectroscopic evidence of MHD shock waves associated with solar flares, specifically identifying a fast-mode shock in soft X-ray ejections.

Findings

Detection of strongly blueshifted emission lines during a solar flare.

Identification of a plasmoid ejection and a shock wave in soft X-rays.

First spectroscopic evidence of an MHD fast-mode shock wave in a flare.

Abstract

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.