ner_tags: O O O B-Software O B-Model O O O O O O O O O B-Telescope O O O O O O O O O B-Software O O O O O O O O O O O O O O O O O O O O B-Telescope O O O O O O B-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O B-Telescope O O O O O O O O O O O O O O O O O O O O O O O O B-Formula I-Formula I-Formula I-Formula I-Formula O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Wavelength I-Wavelength I-Wavelength I-Wavelength O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Software O O O O O O O O O O O O O O O O O O O O O O O B-Observatory B-Telescope O O B-Observatory I-Observatory I-Observatory B-Telescope I-Telescope I-Telescope O B-Observatory B-Telescope O O O O O O O O O O O O O O B-CelestialObject O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Software O O O O O B-Wavelength O B-Wavelength I-Wavelength O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-CelestialObjectRegion I-CelestialObjectRegion O O O B-CelestialObject O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Wavelength I-Wavelength O O
tokens: yet implemented in SPECTRUM or AWSoM. The comparison of the coronal hole emission with the EIT images is also misleading for two reasons. First, the SPECTRUM calculations have been carried out with the two fundamental limitations discussed above; second, the coronal hole count rates of the EIT images are affected by instrument-scattered light (Shearer et al. 2012 ), and thus they are an overestimate of the real emission of coronal holes. These limitations prevent us from drawing any conclusions from the comparison with EIT. Finally, we assumed that the kinetic proton and ion temperatures are equal. However, in the region of the data extraction, the proton temperature anisotropy, T ⊥ / T ∥ , is between 1 and 1.3. In regions where there is temperature anisotropy, the kinetic proton and ion temperatures are not equalized by Coulomb collisions. 4.1.3. Sulfur The total intensity of the S x 264.2 Å line is significantly underestimated in both models even if lines formed at similar temperatures are in agreement with observations for the west limb. The reason for this discrepancy is likely due to the assumed abundance of sulfur. The values adopted in this study are photospheric, but the abundance of this element is notoriously difficult to determine because sulfur behaves in an anomalous way with regard to the FIP effect. In fact, sometimes it can behave as a high-FIP element, and sometimes as a low-FIP element, depending on the properties of the region where it is emitted (Laming 2015 , and references therein). Therefore, while the comparison of the predicted intensity of this element is expected to follow the behavior of the other ions formed at similar temperatures (e.g., Fe xi–xii ), the uncertainties in the element abundances make its interpretation more difficult. 4.2. Narrowband and Spectral Imaging SPECTRUM has the capability to apply instrument effective areas on the calculated intensities and to create 2D narrowband images, such as those observed by SoHO /EIT or the Solar Dynamic Observatory /Atmospheric Imaging Assembly ( SDO /AIA). To obtain such images, we need to save the 3D data domain surrounding the Sun. Then we calculate synthetic spectra for each pixel, weighting it by the effective area of the instrument and calibration factors. Figure 13 was created based on a box with sides of 3 R ⊙ in length, with 200 cells along each side. SPECTRUM calculated the full spectra from 165 to 350 Å for each cell within the box and convolved them with the instrument’s response function to obtain the observed data number count (DN) measured with the imager. The top left panel in Figure 13 shows the simulated plasma conditions of the solar corona as observed from Earth on 2007 November 4 19:12:27 UT, the top right panel corresponds to 2007 November 12 12:32:02 UT, and the bottom one is at 2009 April 23 13:13:36 UT, corresponding to the closest time to the spectral observations when narrowband observations were taken at the 195 Å wavelength. The