Multi-scale processes at the transition region of the Earth’s magnetotail

The interaction between localized fast plasma jets, called bursty bulk flows (BBF) or flow bursts and ambient magnetic field plays an important role in the complex chain of solar wind-magnetosphere-ionosphere coupling processes.  In particular the transition region, where the magnetic field configuration changes from dipolar-like configuration to tail-like configuration and where near-Earth flow braking/bouncing processes take place, is a key region of fundamental processes such as the particle energization and wave-particle interaction. These processes, associated with magnetic and pressure disturbances, drive enhanced energy and momentum transfer from the nightside outer magnetosphere along Earth’s magnetic field lines down to the ionosphere. Across the field lines, particle injections further affect the inner magnetosphere dynamics, constituting a source population for the radiation belt and the ring current.

In this presentation we stress the importance of observations of BBFs and dipolarization fronts by multi-point measurements in an extensive region covering both equatorial and off-equatorial  locations, and simultaneously at ion and fluid scales for understanding the energy transport processes. These allows us to monitor both the field-aligned and perpendicular evolution of the flux tube and enable to study the coupling with the ionosphere.  By showing several examples of observations from previous studies of different scales of disturbances and fortuitous multi-spacecraft configuration at different scales, the 3D nature of the interaction between the BBF and ambient plasma, and its relationship to ionosphere including field-aligned current and aurora will be discussed.