We studied the space weather effects on the South Atlantic Anomaly (SAA) magnetic response using Tsyganenko models. For the physical parameters characterizing the SAA, the study considered the minimum magnetic field, the location (longitude and latitude) of the SAA center, and the area of the SAA. Regarding the space weather parameters, we considered the solar wind dynamic pressure, the interplanetary magnetic field components, $$B_{yIMF}$$ B yIMF and $$B_{zIMF}$$ B zIMF , the Dst index, and the geodipole tilting angle. To study the magnetic field response of the SAA, several different versions of the Tsyganenko models, namely, T96, T01, and TS05, were used to describe the external magnetic field contributions. The main internal magnetic field was calculated by the International Geomagnetic Reference Field (IGRF-12). The magnetic field study of the SAA was realized in long- and short-term (seasonal and diurnal) variations. We found that the Dst index and the geodipole tilting angle were the strongest influencing parameters on the SAA magnetic field response at all altitudes. Moreover, it was revealed that both magnetic poles might be a possible cause of the SAA magnetic field response, resulting from the space weather conditions. Furthermore, the magnetic field behavior of the SAA was affected by hourly variations, where the largest changes occurred at dayside.

<p>In this study, we assess the hourly variations of the three-dimensional proton flux distribution inside the South Atlantic Anomaly (SAA) during a geomagnetic storm. We have developed a relativistic three-dimensional guiding center test particle simulation code in order to compute the proton trajectories in a time-varying magnetic field background provided by Tsyganenko model TS05 and the corresponding time-varying inductive electric field. The Dst index is the main input parameter to the simulation model, while the maximum proton flux, the area of the SAA calculated below a selected threshold, and the penetration depth of the protons are the main output variables investigated in this study were. Since the LEO spacecraft and human-related activities are already affected by space weather conditions, the South Atlantic Anomaly (SAA) is also believed to create an additional source of risk. As the radiation environment depends essentially on the particle flux, the objective of this study is to estimate quantitatively the proton flux variations inside the South Atlantic Anomaly (SAA) in quiet and in storm conditions. So far, it was found that after several drift periods, the protons in the South Atlantic Anomaly (SAA) could penetrate to lower altitudes during geomagnetic storm event, and that, the SAA maximum flux value and the corresponding area, varied differently with respect to altitudes. Numerical results were compared with observations by NOAA 17 and RD3R2 instrument mounted on International Space Station (ISS).</p>

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