Different Patterns of Chromospheric Evaporation in a Flaring Region Observed with Hinode/EIS

TL;DR

This study analyzes chromospheric evaporation patterns during a solar flare using Hinode/EIS data, revealing diverse flow behaviors at different flare ribbon points, indicating multiple heating mechanisms.

Contribution

It provides detailed observations of varying evaporation patterns at multiple flare ribbon points, highlighting the complexity of heating processes during solar flares.

Findings

Different flow patterns observed at three flare ribbon points.

Presence of both upflows and downflows with temperature dependence.

Evidence of multiple heating mechanisms in the flaring region.

Abstract

We investigate the chromospheric evaporation in the flare of 2007 January 16 using line profiles observed by the EUV Imaging Spectrometer (EIS) onboard Hinode. Three points at flare ribbons of different magnetic polarities are analyzed in detail. We find that the three points show different patterns of upflows and downflows in the impulsive phase of the flare. The spectral lines at the first point are mostly blue shifted, with the hotter lines showing a dominant blue-shifted component over the stationary one. At the second point, however, only weak upflows are detected; in stead, notable downflows appear at high temperatures (up to 2.5-5.0 MK). The third point is similar to the second one only that it shows evidence of multi-component downflows. While the evaporated plasma falling back down as warm rain is a possible cause of the redshifts at points 2 and 3, the different patterns of chromospheric evaporation at the three points imply existence of different heating mechanisms in the flaring active region.