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Paper: Two Components of the Coronal Emission Revealed by Both Spectroscopic and Imaging Observations
Volume: 456, The Fifth Hinode Science Meeting
Page: 97
Authors: Tian, H.; McIntosh, S. W.; De Pontieu, B.
Abstract: X-ray and EUV imaging observations often reveal quasi-periodic propagating disturbances along the fan-like structures at edges of active regions. These disturbances have historically been interpreted as being signatures of slow-mode magnetoacoustic waves propagating into the corona. Recent spectroscopic observations have revealed the ubiquitous presence of blueward asymmetries of EUV emission line profiles. Such asymmetries suggest that there are at least two emission components: a primary component accounting for the background emission and a secondary component associated with high-speed upflows. Thus, a single Gaussian fit can not reflect the real physics here. Through joint imaging and spectroscopic observations, we find a clear association of the secondary component with the upward propagating disturbances and conclude that they are more likely to be real plasma outflows (small-scale recurring jets) rather than slow waves. These outflows may result from impulsive heating processes in the lower transition region or chromosphere and could be an efficient means to provide hot plasma into the corona and possibly also solar wind.
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