Determinants of Electron Heating Efficiency in Magnetotail Reconnection

Determine the physical parameters and processes that control the efficiency of electron heating mechanisms during anti-parallel collisionless magnetic reconnection in the Earth's magnetotail, with particular emphasis on acceleration by magnetic-field-aligned electric fields (E_parallel).

Background

Magnetic reconnection converts electromagnetic energy into particle energy, with multiple mechanisms contributing to electron heating. Among these, acceleration by magnetic-field-aligned electric fields (E_parallel) has been identified as important but its efficiency relative to other mechanisms is not fully understood.

The paper investigates electron heating by E_parallel in magnetotail reconnection using MMS observations, quantifying an acceleration potential and its scaling with upstream parameters. Despite these advances, the authors explicitly note that what governs the efficiency of the various electron heating mechanisms, particularly E_parallel acceleration, remains unclear, motivating further investigation into controlling factors.