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We performed a systematic study of 12 active regions (ARs) with a broad range of areas, magnetic flux and associated solar activity in order to determine whether there are upflows present at the AR boundaries and if these upflows exist, whether there is a high speed asymmetric blue wing component present in the upflows. To identify the presence and locations of the AR upflows we derive relative Doppler velocity maps by fitting a Gaussian function to {it Hinode}/EIS Fe XII 192.394,AA line profiles. To determine whether there is a high speed asymmetric component present in the AR upflows we fit a double Gaussian function to the Fe XII 192.394,AA mean spectrum that is computed in a region of interest situated in the AR upflows. Upflows are observed at both the east and west boundaries of all ARs in our sample with average upflow velocities ranging between -5 to -26~km s$^{-1}$. A blue wing asymmetry is present in every line profile. The intensity ratio between the minor high speed asymmetric Gaussian component compared to the main component is relatively small for the majority of regions however, in a minority of cases (8/30) the ratios are large and range between 20 to 56~%. These results suggest that upflows and the high speed asymmetric blue wing component are a common feature of all ARs.
We present a study of the temporal evolution of coronal loops in active regions and its implications for the dynamics in coronal loops. We analyzed images of the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) at multiple t
The recent analysis of observations taken with the EIS instrument on Hinode suggests that well constrained measurements of the temperature distribution in solar active regions can finally be made. Such measurements are critical for constraining theor
Spectroscopic observations at extreme and far ultraviolet wavelengths have revealed systematic upflows in the solar transition region and corona. These upflows are best seen in the network structures of the quiet Sun and coronal holes, boundaries of
It is generally agreed that small impulsive energy bursts called nanoflares are responsible for at least some of the Suns hot corona, but whether they are the explanation for most of the multi-million degree plasma has been a matter of ongoing debate
We use observations of line-of-sight magnetograms from Helioseismic and Magnetic Imager (HMI) on board of Solar Dynamics Observatory (SDO) to investigate polarity separation, magnetic flux, flux emergence rate, twist and tilt of solar emerging active