Evolution of dipolarisation fronts in a 3D global hybrid-Vlasov simulation

Magnetic reconnection and plasma instabilities in Earth's magnetotail can lead to dipolarisation fronts (DFs), rapid enhancements of the magnetic field component aligned with Earth's magnetic dipole axis. DFs are often associated with channels of fast plasma flow, and they accelerate particles and transport magnetic flux to the inner magnetosphere. Satellite observations suggest that DFs propagate Earthward until they decelerate and either vanish, rebound or deflect as they reach the transition region between tail-like and dipole-like magnetic field configurations.

We study the evolution and characteristics of DFs in a global magnetospheric simulation conducted using Vlasiator, a 3D hybrid-Vlasov code that solves ion dynamics by evolving the ion distribution functions explicitly. Events are identified using a magnetic field time derivative threshold, and individual fronts are tracked from their formation to their termination. Preliminary results show how magnetic forces affect the propagation of DFs and how energy is converted as the fronts develop. Tracking the evolution of DFs in global simulations offers a complementary point of view to satellite observations, where following individual fronts is often impossible.