Energy Partition and Balance at Dipolarization Fronts

Dipolarization fronts (DFs) have been documented as important structures contributing to energy conversion and flux transport in Earth's magnetotail. However, energy partition and balance at DFs still remain elusive. Using high-cadence data from NASA's Magnetospheric Multiscale mission, we preform a comprehensive investigation of energy budgets at the DFs. We find that material derivatives of particle energy densities in the DF frame are basically close to zero, indicating that particles experience negligible heating and/or acceleration and that the energy released at the DFs is predominantly manifested in the form of energy flux. The energy flux is found to be dominated by ion and electron enthalpy flux, ion heat flux, and Poynting flux, with electron enthalpy flux being locally elevated. In addition, the energy flux tends to increase during the DFs' earthward propagation, without exhibiting clear asymmetry in the dawn-dusk direction. These results help further understand energy budgets at the DFs.