Statistical Properties of Current, Energy Conversion, and Electron Acceleration in Flux Ropes in the Terrestrial Magnetotail

We perform a statistical analysis on current density, energy conversion, and electron acceleration in the primary flux ropes (PFRs) and the secondary flux ropes (SFRs) distinguished by out-of-plane electron current, respectively. It is found that current filaments are plentiful in both PFRs and SFRs. The closer to the center of the SFRs, the stronger the |J| is. The J center dot E ' is intermittent in the PFRs. However, J center dot E ' almost stays positive in the SFRs. The local adiabatic acceleration of the electrons in the PFRs and the SFRs are explored. Fermi and betatron acceleration are closely related to the adjacent magnetic field and bulk flow which can lead to the contraction/relaxation of the PFRs and SFRs and enhance/reduce the gradient of the magnetic field. The acceleration by the parallel electric field is significant in the SFRs. Our results can help to improve the understanding of the PFRs and SFRs and their roles in the magnetotail dynamics.

Automated summary

A statistical analysis was performed on current density, energy conversion, and electron acceleration in primary and secondary flux ropes, showing differences and patterns that can enhance understanding of their roles in magnetotail dynamics.