Determination of Current Density in Magnetospheric Plasma: Multispacecraft and Particle Approaches

A comparative analysis of two methods for determining electric current density in the near-Earth magnetospheric plasma is presented: the multispacecraft curlometer technique and the particle-based (kinetic) approach relying on plasma moments. The study is based on data from the Magnetospheric Multiscale Mission (MMS) for six magnetic reconnection events in Earth’s magnetotail observed between 2019 and 2024. It is shown that the results of both methods agree well under conditions of stable spacecraft configuration and the absence of radiation contamination in the measurements. The particle-based approach systematically yields overestimated current densities, likely due to locally enhanced ion density near the spacecraft. Spectral analysis reveals that particle-derived data exhibit increased noise levels at frequencies above 1 Hz. The obtained results are important for refining our understanding of energy-dissipation mechanisms and the dynamics of magnetic reconnection processes.