Assessing the Role of Turbulence-Driven Magnetic Reconnection in the Dissipation of Plasma Turbulence in Earth’s Magnetosheath

Abstract

Magnetic reconnection has long been thought to play an important role in turbulent plasmas – with the nonlinear dynamics of turbulent systems being well known to self-consistently generate intense current structures and associated magnetic shears that can be sites where so-called turbulence-driven magnetic reconnection can occur. However, complex three-dimensional magnetic topologies and the small-scale nature of these magnetic reconnection events have traditionally made it challenging to assess the role of magnetic reconnection in the turbulent dynamics from either a numerical or observational perspective. Recent high-resolution observations from NASA’s Magnetospheric Multiscale (MMS) mission have provided an unprecedented new opportunity to systematically examine turbulence-driven reconnection in the region of shock-driven turbulence within Earth’s magnetosheath. These observations have provided new insight into the nature of magnetic reconnection within turbulent plasmas, revealing that under the right conditions so-called electron-only magnetic reconnection, in which ion jets are not accelerated by the newly reconnected magnetic fields, can occur. In this talk, we explore how to observationally constrain the contribution turbulence-driven magnetic reconnection makes to the energy dissipation rate of the turbulence. We then directly compare estimates of the dissipation rate associated with reconnection events observed by MMS to estimates of the turbulent energy cascade rate for the specific intervals of magnetosheath turbulence that the reconnection events are observe within. The potential implications of traditional ion-coupled reconnection versus electron-only reconnection for the energy budget of turbulent dissipation and the magnetosheath overall are then discussed in detail.