Energy Conversion and Transport in Dayside Electron Diffusion Regions.

The electron diffusion region (EDR) is believed to be a key region for the conversion of energy associated with magnetic reconnection from magnetic to kinetic and thermal, but the nature of energy transport and conversion in EDRs is still not well understood. In this work, we capitalise on recent studies that have increased the number of referenced EDRs observed by MMS and perform a statistical study of 80 near X-line events previously identified in the literature. Upon detailed analysis, MMS was found to be located within the inner EDR for 45 of these events, while others correspond to outer EDR or IDR crossings.
We investigate energy partition in their vicinity and find that the electron enthalpy flux dominates within the EDRs compared to the bulk kinetic and heat fluxes. We then evaluate the stationary terms of the energy conservation equation and find that large fluctuations of the electron enthalpy flux divergence tend to occur in the EDRs, suggestive of a complex energy transfer process dominated by the internal energy flux contribution. We also examine the possible role of magnetic shear/guide field, but this is somewhat limited by the fact that many events occur at relatively high shear and low guide field conditions. We conclude with considering how in future work, comparing these results to magnetotail- (symmetric) and magnetosheath- (low shear) EDR may bring further insight into how the regime in which magnetic reconnection occurs can impact the energy conversion and transport.