The effect of South Atlantic Anomaly on ring current dynamics

The South Atlantic Anomaly (SAA) affects particle evolutions and loss processes in the inner magnetosphere. However, most existing models simplify precipitation calculations by averaging the north-south loss cone, neglecting the SAA's impact. Using the Storm-Time Ring Current Model (STRIM) accounting for the SAA effect, we simulate a storm event to analyze electron precipitation in both hemispheres. Results show electron decay near the SAA is significantly larger than in other regions around L = 4. Previous Average methods underestimated electron precipitating fluxes in the southern hemisphere. 
Furthermore, SAA significantly promotes low-energy (several keV) electron precipitation compared to high-energy (hundreds of keV) electrons. Comparisons with in-situ observations indicate that simulations considering the SAA effect capture the intensity and variations of electron precipitation. This study emphasizes the necessity of including the SAA effect in models for accurately interpreting ring current electron dynamics and the north-south asymmetry of electron precipitation.