Coronal plasma motions near footpoints of active region loops revealed from spectroscopic observations with Hinode EIS.
ASTROPHYS J LETT
L67 - L71.
The solar active region 10938 has been observed from the disk center to the west limb with the Hinode EUV Imaging Spectrometer. In the disk-center observation, subsonic upflow motions of tens of km s(-1) and enhanced nonthermal velocities have been found near the footpoints of the active region loops assuming a single Gaussian approximation for the emission-line profiles. When the same part of the active region is observed near the limb, both upflows and enhanced nonthermal velocities essentially decrease. There is a strong correlation between Doppler velocity and nonthermal velocity. Significant deviations from a single Gaussian profile are found in the blue wing of the line profiles for the upflows. These suggest that there are unresolved high-speed upflows. We discuss the implications for coronal heating mechanisms.
|Title:||Coronal plasma motions near footpoints of active region loops revealed from spectroscopic observations with Hinode EIS|
|Keywords:||Sun : atmospheric motions, Sun : corona, Sun : UV radiation, EUV IMAGING SPECTROMETER, SOLAR CORONA, EMISSION-LINES, DISSIPATION, MISSION, FIELDS, MODEL|
|UCL classification:||UCL > School of BEAMS > Faculty of Maths and Physical Sciences > Space and Climate Physics|
Archive Staff Only