Sistema de corriente sq en el observatorio geomagnético de fúquene y su relación con el modelo difi-7

Abstract

This undergraduate thesis, with a focus on scientific research, centers on the study of solar quiet variation (Sq) of the ionospheric magnetic field at the Fúquene Geomagnetic Observatory (FUQ), as well as its comparison with the global model DIFI-7. It begins with a theoretical review of the sources of the geomagnetic field, both internal (core and Earth's crust) and external (ionosphere and magnetosphere). The main ionospheric current systems are described, such as the Equatorial Electrojet (EEJ), the Auroral Electrojet (AEJ), and the Sq system, analyzing their generation, behavior, and scientific relevance. Subsequently, the operation, history, and instrumentation of the Fúquene Geomagnetic Observatory are described, including the methodology used for the digitization of historical magnetograms and data acquisition. The residual of the observed ionospheric field is calculated by subtracting the contributions of both internal and external components, modeled by CHAOS-8, and it is compared with the predictions from the DIFI-7 model for different geomagnetic periods: one quiet period between October 2 and 9, 2014, and one disturbed period between May 8 and 15, 2024. The results show a good correspondence between the modeled and observed signals under conditions of low geomagnetic activity. We found that the differences between the residual and the model range from 0.14 to 33.4 nT in the radial component, from 0.13 to 26 nT in the polar component, and from 0.05 to 25.56 nT in the azimuthal component. Meanwhile, under conditions of high geomagnetic activity, the differences between the residual and the model range from 0.3 to 91.85 nT in the radial component, from 0.18 to 224.18 nT in the polar component, and from 0.06 to 87.97 nT in the azimuthal component, which are associated with the model's sensitivity to large changes caused by geomagnetic storms. This study demonstrates the usefulness of the DIFI-7 model for representing the Sq current in Colombia and validates the quality of the data obtained by the FUQ observatory, thus opening new possibilities for the monitoring and modeling of the geomagnetic field in equatorial regions.