Out-of-plane Parallel Current in the Diffusion Regions: The Interaction Between Diffusion Region Systems and their Impact on the Outer EDR

TL;DR

This paper investigates the out-of-plane parallel currents in Earth's magnetopause diffusion regions, revealing their role in system interactions and energy dissipation through combined observational and simulation analysis.

Contribution

It identifies out-of-plane parallel current signatures as key features of the outer EDR and IDR, advancing understanding of their interaction and energy transfer mechanisms.

Findings

Out-of-plane parallel currents are characteristic of the outer EDR and IDR.

Interactions between diffusion region systems influence energy dissipation.

Simulation results align with observational data on current signatures.

Abstract

Dayside magnetic reconnection allows for the transfer of the solar wind's energy into Earth's magnetosphere. This process takes place in electron diffusion regions (EDRs) embedded in ion diffusion regions (IDRs), which form in the magnetopause boundary's current sheet. A significant out-of-plane parallel current contribution in the diffusion regions was reported in Beedle et al. 2023. In order to understand the underlying structure of this parallel current, we compared EDR statistical results with a 2.5D Particle-In Cell (PIC) simulation. From this comparison, we identified out-of-plane parallel current signatures as defining features of the outer EDR and IDR. This significant out-of-plane parallel current indicates the interaction of the IDR and EDR systems, and provides implications for not only understanding energy dissipation in the diffusion regions, but also determining the location of the outer EDR.