Correcting Doppler Shifts in He II 30.38 nm Line by Using the EVE and AIA Data from Solar Dynamics Observatory

Abstract The Extreme-ultraviolet Variability Experiment (EVE) onboard the Solar Dynamics Observatory detects solar EUV spectra with high temporal cadence and spectral resolution. wavelength shifts of emission lines provide key information dynamics Sun. However, some EVE observations are influenced by non-uniformly distributed irradiance on Sun, which may prevent us from correctly understanding physical processes happening in corona. Here, based only published on-orbit calibration data He II 30.38 nm line 2011 January 27, we develop a method to correct using AIA 304 imaging data. This correction is then applied 2010 October 29 March 3 study Doppler oscillations line, show that half-month periodic oscillation caused mainly due presence active regions. Other coronal also present similar oscillations, suggesting an appropriate must be implemented before interpreting phenomena appearing these lines.