Small-scale Properties of Magnetotail Dipolarization Fronts observed by MMS
Magnetotail dipolarizations fronts (DFs) are a key ingredient of magnetotail dynamics and play an important role in the energy and magnetic flux transportation from the distant tail towards the Earth. They are characterized by a rapid increase in the northward magnetic field component (Bz) perpendicular to the current sheet. Spacecraft observations of DFs have been reported in a large portion of the magnetotail for over more than three decades and are still a hot topic in magnetospheric physics. However, still little is known about the exact evolution process of the DFs as they propagate earthward.
Here we present a multicase study on the temporal and spatial properties of the DFs observed by the Magnetopheric Multiscale (MMS) mission during spring 2017 when MMS’s apogee is located in the Magnetotail around 25RE. MMS consists of four identical spacecraft which fly in a tetrahedral configuration with inter-spacecraft distances below 100 km. This specific configuration together with the unprecedented ultra-fast plasma in-situ measurements, allow us for the first time to study the small-scale spatial and temporal properties of DFs.
The results presented in this study will give a better understanding of the small-scale properties of the DFs and how the kinetic and magnetic energy is converted at the DF while this microscopic structure remains largely stable during propagating macroscopic distances in the magnetotail.