The Success of MMS in Characterizing Electron Diffusion Regions During Reconnection in the Earth’s Magnetosphere.
Presentation Type
Talk
Presenter Format
In Person Meeting Talk
Topic
Fundamental Processes in Comparative Magnetospheres
Start Date
13-5-2022 11:30 AM
Abstract
A major science goal of the MMS mission is “to reveal, for the first time, the small-scale three-dimensional structure and dynamics of the elusively thin and fast-moving electron diffusion region”. The mission has been hugely successful in accomplishing this goal, where remarkable and detailed data have been obtained for a large number of electron diffusion regions (EDRs) encounters. In this talk I will review results for three of the perhaps most studied EDRs [1,2,3]. First, in the dayside magnetopause strong density asymmetries yield crescent shaped features in the electron velocity distributions [1] over a range along the topological separator [4], whereas within the EDR the frozen-in-law is broken by dynamics of oblique electron beams [5]. In the Earth magnetotail, perfectly symmetric and anti-parallel reconnection has been observed [2], which permitted a direct evaluation of the off-diagonal electron pressure stress elements responsible for reconnection [6]. Reconnection with a weak guide-field has also been observed [3], which together with trapped electron dynamics and associated electron pressure anisotropy impact the Regime-type of the EDR [7,8].
The Success of MMS in Characterizing Electron Diffusion Regions During Reconnection in the Earth’s Magnetosphere.
A major science goal of the MMS mission is “to reveal, for the first time, the small-scale three-dimensional structure and dynamics of the elusively thin and fast-moving electron diffusion region”. The mission has been hugely successful in accomplishing this goal, where remarkable and detailed data have been obtained for a large number of electron diffusion regions (EDRs) encounters. In this talk I will review results for three of the perhaps most studied EDRs [1,2,3]. First, in the dayside magnetopause strong density asymmetries yield crescent shaped features in the electron velocity distributions [1] over a range along the topological separator [4], whereas within the EDR the frozen-in-law is broken by dynamics of oblique electron beams [5]. In the Earth magnetotail, perfectly symmetric and anti-parallel reconnection has been observed [2], which permitted a direct evaluation of the off-diagonal electron pressure stress elements responsible for reconnection [6]. Reconnection with a weak guide-field has also been observed [3], which together with trapped electron dynamics and associated electron pressure anisotropy impact the Regime-type of the EDR [7,8].
