Particle-in-cell Simulation of Energy Conversion at the Turbulent Region Downstream of the Reconnection Front

We study the energy conversion in the turbulent region (TR) downstream of the reconnection front (RF) via 2.5D particle-in-cell simulations. Our study shows that most magnetic energy is transferred into plasma in the exhaust region (ER) and the TR downstream of the RF; the latter is formed due to the electron Kelvin-Helmholtz instability (KHI). Unlike the energy conversion in the ER, the energy conversion in the TR is mainly balanced by its in-plane component (E (x) J (x) +E (z) J (z) ). We further find that the time evolution of the integrated energy conversion in the TR is strongly correlated with the time evolution of the electron KHI and secondary reconnection. The KHI feeds on the electron kinetic energy to grow, and electron vortices are formed, correspondently. The energy is transferred to ions through a nonideal electric field associated with those electron vortices after the KHI is well developed. Finally, the electron vortices are collapsed due to the secondary reconnection among those vortices. The power law of the magnetic energy spectra also shows a slope near -5/3 at wavenumbers larger than the ion scale when the KHI is fully developed.

Automated summary

We investigate the energy conversion in the turbulent region downstream of the reconnection front through 2.5D particle-in-cell simulations. Our findings reveal that a significant amount of magnetic energy is transferred into plasma both in the exhaust region and the turbulent region, which is formed due to the electron Kelvin-Helmholtz instability. Unlike the energy conversion in the exhaust region, the energy conversion in the turbulent region is mainly balanced by its in-plane component. Furthermore, the time evolution of the integrated energy conversion in the turbulent region is strongly correlated with the electron Kelvin-Helmholtz instability and secondary reconnection. The energy is transferred to ions through a nonideal electric field associated with the electron vortices formed during the development of the instability.