Energy Partitioning Between Thermal and Non-Thermal Electrons and Ions in Magnetotail Reconnection

Magnetic reconnection is an explosive energy release event. It plays an important role in accelerating particles to high non-thermal energies. These particles often exhibit energy spectra characterized by a power-law distribution. However, the partitioning of energy between thermal and non-thermal components, and between ions and electrons, remains unclear. This study provides estimates of energy partition based on a statistical analysis of magnetic reconnection events in Earth's magnetotail using data from the Magnetospheric Multiscale mission. Ions are up to 10 times more energetic than electrons but have softer spectra. We found for both ions and electrons that, as the average energy of particles (temperature) increases, their energy spectra become softer (steeper) and thus, the fraction of energy carried by the non-thermal components decreases. These results challenge existing theories of particle acceleration through magnetotail reconnection.