Effect of Geomagnetic Storm on O+(2P) 732.0 nm Dayglow Emission

English Abstract:

A comprehensive model is developed to study O⁺(²P) 732.0 nm dayglow emission. The Solar2000 EUV (extreme ultraviolet) flux model, neutral atmosphere model (NRLMSISE-00), latest transition probabilities and updated reaction rate coefficients are incorporated in the present model. The modeled volume emission rates (VER) are compared with the measurements as provided by Atmosphere Explorer-C satellite, Dynamics Explorer-2 spacecraft and WINDII measurements. The model is found in very good agreement with the measurements. This model is used to study the effects of geomagnetic activity on the O⁺(²P) 732.0 nm dayglow emission at a low latitude station Tirunelveli (8.7⁰N,77.8⁰E). It is found that the volume emission rate shows the negative correlation with the Dst index. The atomic oxygen number densities obtained from the NRLMSISE-00 model during a geomagnetic storm are compared with the measurements. It is found that the atomic oxygen number densities given by NRLMSISE-00 model are significantly lower than the measured values. Consequently, the atomic oxygen number density in the present model is varied under the limit of measurements to study its effect on 732.0 nm dayglow emission. An increase of more than 50% in the zenith intensity above the normal level (before the onset of the storm) is found when the atomic oxygen number density is doubled in the model.