Energy conversion and flow in the asymmetric magnetic reconnection layer in laboratory and space plasmas *

The dynamics and physical mechanisms governing the transfer of magnetic energy to plasma particles are comparatively studied during asymmetric reconnection in both laboratory and space plasmas and within the context of two-fluid physics. Despite huge differences in the physical size of the reconnection layer, 30 cm in the MRX (Magnetic Reconnection Experiment) versus ~500 km at the magnetopause (MMS), remarkably similar characteristics are observed in both plasma dynamics and energy deposition profiles. Specifically, in a strongly asymmetric reconnection layers, in which the plasma density on one side of plasma inflow is significantly larger (>10) than the other, it is found that without guide field, the energy deposition to electrons primarily occurs through j_e⏊·E_⏊ in the electron diffusion region. A modified saddle-back-shaped large potential well is observed within the reconnection plane due to the dynamics of the electron current in the layer, and ions are accelerated at the exhaust region resulting in strong ion heating. We find that nearly 60 % of the incoming magnetic energy is transferred to ions and electrons in almost equal portions while the remainder is transported out to the exhaust region.