Force and Energy Balance of the Dipolarization Front

We have performed a particle‐in‐cell simulation to understand the dynamic evolution of the dipolarization front during its early stage after ejected by magnetic reconnection, focusing on the force and energy balance around the dipolarization front. We track the temporal evolution of the force and different energy channels in the Lagrangian frame of the dipolarization front. We find that the curvature force continuously accelerates the dipolarization front moving outward, while the thermal pressure gradient force hinders the movement of the DF. The DF is accelerated outward because the total force is positive. The maximum value of B z at the DF gradually increases during the outward propagation of the front. Although the dipolarization front is the site with significant energy conversion from the magnetic field to plasma, that is, J  ·  E  > 0 , the compression of the magnetic field by the convergent flow at the front leads to the gradual enhancement of B z . The released magnetic energy bulk accelerates and heats the plasma. The plasma thermal energy increases at the front that is primarily due to the work of the pressure gradient ( v  · ( ∇  ·  P ) > 0 ), while the enthalpy flux emitted from the front reduces the thermal energy. Both the pressure‐strain interaction −( P ′ ·  ∇ ) ·  v and the pressure dilation p ∇  ·  v contribute to the ion and electron temperature enhancement. Our results are important for revealing the dynamic evolution of the dipolarization fronts and will aid us to understand the energy transport in the disturbed magnetotail.