Observations of plasma upflow in a warm loop with Hinode/eis

Abstract

A complete understanding of Doppler shift in active region loops can help probe the basic physical mechanism involved into the heating of those loops. Here, we present observations of upflows in coronal loops detected in a range of temperatures (log T = 5.8-6.2). The loop was not discernible above these temperatures. The speed of upflow was strongest at the footpoint and decreased with height. The upflow speed at the footpoint was about 20kms-1 in Fe VIII, which decreased with temperature, being about 13kms-1 in Fe X, about 8kms-1 in Fe XII, and about 4kms-1 in Fe XIII. To the best of our knowledge, this is the first observation providing evidence of upflow of plasma in coronal loop structures at these temperatures. We interpret these observations as evidence of chromospheric evaporation in quasi-static coronal loops. © 2012. The American Astronomical Society. All rights reserved.