Speaker
Description
The South Atlantic Magnetic Anomaly (SAMA) represents a unique low-intensity region of the geomagnetic field, where the inner radiation belt approaches the upper atmosphere, enhancing particle precipitation and ionospheric conductivity. In this work, we investigate how SAMA modulates the ground magnetic response during Sudden Commencements (SCs) and associated Pc5 pulsations. Using data from a global network of geomagnetic stations, including conjugate pairs across different longitudinal sectors, we derived new dimensionless indices (A-SC, V-SC, PA-SC, and Pc5-SC) to quantify amplification effects. Our results show that stations located under the SAMA exhibit systematically higher SC amplitudes and faster variation rates, with São Martinho da Serra (SMS) displaying up to 1.8× amplification relative to its northern conjugate. The accumulated disturbance index (PA-SC) proved to be the most sensitive parameter, integrating both the SC impulse and subsequent Pc5 wave energy. These findings highlight the importance of regional ionospheric conditions in shaping the geomagnetic response to solar wind compressions, and suggest that PA-SC can serve as a comparative tool to assess energy deposition across different ionospheric environments.
