Observational Analysis of In Situ Ring Current Density: A Multi-Mission, Multi-Perspective, and Multi-Spacecraft Approach

We systematically compare and analyze diverse methodologies for calculating space current density, with a particular focus on examining the insights and challenges associated with the Curlometer method. Employing these methodologies, we conduct an in-depth analysis of an event characterized by elevated calculated current densities, delving into its physical authenticity. Statistical analysis of the long-term measurements of particle and magnetic field values from multiple missions is also employed to investigate the distribution characteristics of current density within the ring current region. Despite the inherent limitations in the available data coverage, which preclude a comprehensive revelation of the spatial topology of the entire ring current, our preliminary findings indicate a season-dependent warping structure in the ring current, in both latitude and local time. This structural variation is fundamentally attributed to the combined influence of the Earth dipole field tilt and solar wind. These results are anticipated to contribute to the understanding of magnetospheric current systems, particularly elucidating the coupling mechanisms between the ring current and other current systems.