We estimate the systematic differences from the peak values of the histograms of the differences between CoMP and EIS Doppler velocities.

Therefore, systematic differences between them might exist. As described before, CoMP and EIS Doppler velocities are relative velocities. After confirming the co-alignment, we compare the CoMP and EIS LOS Doppler velocity (non-thermal width) maps by visual inspection, and examine pixel-to-pixel correlations and percentages of pixel numbers satisfying the condition that the differences between CoMP and EIS spectroscopic quantities are within the EIS measurement accuracies. When we examine their pixel-to-pixel correlations, the correlation coefficients (CCs) are generally high, ranging from 0.70 to 0.98 (average of 0.91 and median of 0.95). We find that they are spatially and temporally consistent overall. Figure 1 shows the CoMP and EIS intensity maps for all events. By using the CoMP and EIS raster scan intensity maps, we check the co-alignment of CoMP and EIS data. Second, we take the pixels closest to the scan positions. Since CoMP and EIS data have slightly different temporal cadences and spatial resolutions, we use the following procedure: First, we select the closest CoMP images before or after EIS raster scans under the condition that time differences between CoMP observations and EIS raster scans should be smaller than 30 seconds. In order to compare the spectroscopic quantities obtained from CoMP and EIS data, we construct pseudo raster scan CoMP maps (e.g., intensity, LOS Doppler velocity, and non-thermal width maps) by using the time and slit position for each EIS scan. Here, about twenty wavelength data sets (spectral lines ranging from 194.9 в„« to 195.4 в„« and from 201.8 в„« to 202.3 в„«) of the EIS Fe XII and Fe XIII lines, corresponding to a high spectral resolution of 0.025 в„« are used to derive spectroscopic quantities. The EIS Fe XIII 202.04 в„« lines are used for examining an equatorial quiet region on 6, two polar prominence regions on 2013/02//05/05, and a polar plume region on 7. For this, we compare the two physical quantities measured simultaneously from CoMP Fe XIII 10747 в„« lines and EIS Fe XII 195.12 в„« lines for investigating flaring active region (AR11654 on 0) and two quiescent active regions (AR 1149 on 2012/04//09/01). In this study, we examine whether the CoMP LOS Doppler velocity and non-thermal width obtained by using only the three-wavelength data are reliable or not. If the actual spectral window is narrower than the spectral resolution (1.2 в„«), the measured values might be overestimated.

For example, if the actual spectral line window including strong emission lines is broader than the observed line window (3.6 в„«), the measured CoMP non-thermal line widths might be underestimated. This limitation is likely to affect the Doppler velocity and non-thermal line width measurements. However, it usually obtains the spectroscopic quantities using three-wavelength data at the Fe XIII lines with a low spectral resolution of 1.2 в„«. The EIS provides the spectral line intensities, LOS Doppler velocities, and line widths simultaneously at specific slit positions up to 1.5 R sun.ДЄs described above, since CoMP can provide 2-D Doppler velocity and non-thermal line maps for the off limb corona from 1.05 to 1.40 R sun every 30 seconds, it is suited to examine propagating coronal AlfvГ©n wave signatures on different coronal regions at the same time, and estimate their origins, energy fluxes, and dissipations. On the other hand, the EIS measures high resolution spectra in two wavelength bands, 170-211 в„« and 246-292 в„«, with a high spectral resolution of 0.0223вЂі/pixel and with different sizes of slits (1вЂі and 2вЂі) and slots (40вЂі and 266вЂі). The CoMP provides their peak intensity, LOS Doppler velocity, and line width simultaneously over a field of view (FOV) ranging from 1.05 to 1.40 R sun with high spatial resolution of 4.5вЂі/pixel and temporal cadences of 30 seconds. Here, the CoMP measures the linear polarization of the Fe XIII 10747 в„« and 10798 в„« coronal forbidden emission lines by using three-wavelength data with a low spectral resolution of 1.2 в„«. 2008) and Hinode/EUV Imaging Spectrometer (EIS, Culhane et al.

In order to find the AlfvГ©n wave signatures in the off-limb solar corona, observations of the line of sight (LOS) Doppler velocity and non-thermal line width by Coronal Multichannel Polarimeter (CoMP, Tomczyk et al. It is generally believed that AlfvГ©n waves in the solar corona are one of the main energy sources for coronal heating and solar wind acceleration.

Eis solar