Testing of solar EUV flux models using 5577Å, 6300Å and 7320Å dayglow emissions Original Research Article

The solar EUV flux models as developed by Hinteregger et al. (1981) and Tobiska (1991) are used to study the emission rates of 5577Å, 6300Å and 7320Å dayglow emissions. The Glow model of Solomon (1992) with certain modifications and updated in terms of recent cross sections data and reaction rate coefficients is used to calculate emission rates. The results are compared with Wind Imaging Interferometer (WINDII) data. It is found that the Tobiska flux model explains WINDII measurements of 5577Å quite satisfactorily above 130 km. However, below 130 km none of the model is found to explain the WINDII measurements. Between 100 and 130 km where photodissociation of O2 (1000Å–1300Å) and dissociative recombination of O2+ are the major sources of O(1S), both the solar flux models overestimate quite significantly WINDII measurements. The emission profiles of 6300Å obtained form WINDII measurements are explained quite satisfactorily by Tobiska model above 160 km. Below 160 km where photodissociation of O2(1000Å–1300Å) is the main source of 6300Å, both the models overestimate the WINDII measurements as has been found in the case of 5577Å. The present results indicate that both solar EUV flux models give higher values of solar flux between 1000Å and 1300Å wavelength region. In case of 7320Å emission the Tobiska model is in very good agreement with the WINDII measurements above 220 km. Overall, the results obtained from Tobiska flux model seem to be better than the Hinteregger flux model.