Investigation of inductive electric fields in Earth’s magnetotail using Magnetospheric Multiscale (MMS) multipoint measurements

Abstract: The mutual interaction between the solar wind and the geomagnetic field generates the magnetosphere. The magnetosphere is characterized by many large-scale perturbations, such as substorms, which are responsible for variations in the magnetic field. From theory, we know that a temporal change in the magnetic field corresponds to the appearance of an induced electric field. These electric fields are a major driver for plasma injection and energization. It is therefore important to evaluate the strength of such fields, and to understand how they vary with position and time. To evaluate the strength of inductive electric fields, data gathered by the Magnetospheric Multiscale Mission (MMS) are used. From multipoint measurements performed by the 4 MMS spacecraft, it is possible to directly evaluate the inductive electric fields. The analysis algorithm used is the reciprocal vector and barycentric coordinates method, which allows field interpolation formmultipoint measurements. Once the method is implemented into MATLAB, it is possible to investigate the inductive effects for short time periods (around 4 hours). Once the method is applied to short time periods and it is validated, the whole dataset is computed, making it possible to perform a 3D mapping of inductive effects in the inner magnetotail and correlate their magnitude to solar wind and magnetospheric parameters.