A self-consistent estimate of O + +N2 ± rate coe cient and total EUV solar ¯ux with k < 1050 AÊ using EISCAT observations

• Main Authors: A. V. Mikhailov, K. Schlegel
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: EISCAT
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.210.2174; http://www.ann-geophys.net/18/1164/2000/angeo-18-1164-2000.pdf

Abstract. There are di€erences between existing models of solar EUV with k < 1050 AÊ and between laboratory measurements of the O + +N2 ± reaction rate coe-cient, both parameters being crucial for the F2-region modeling. Therefore, indirect aeronomic estimates of these parameters may be useful for qualifying the existing EUV models and the laboratory measured O + +N2 ± rate coe cient. A modi®ed self-consistent method for daytime F2-region modeling developed by Mikhailov and Schlegel was applied to EISCAT observations �32 quiet summer and equinoctial days) to estimate the set of main aeronomic parameters. Three laboratory measured temperature dependencies for the O + +N2 ± rate coe cient were used in our calculations to ®nd self-consistent factors both for this rate coe cient and for the solar EUV ¯ux model from Nusinov. Independent of the rate coe cient used, the calculated values group around the temperature dependence recently measured by Hierl et al. in the 850±1400 K temperature range. Therefore, this rate coe cient may be considered as the most preferable and is recommended for aeronomic calculations. The calculated EUV ¯ux shows a somewhat steeper dependence on solar activity than both, the Nusinov and the EUVAC models predict. In practice both EUV models may be recommended for the F2-region electron density calculations with the total EUV ¯ux shifted by ‹25% for the EUVAC and Nusinov models, correspondingly. Key words: Ionosphere �ion chemistry and composition; ionosphere atmosphere interactions; modeling and forecasting)