Observation of high-shear bifurcated electron-scale current sheet at the magnetopause
(English)Manuscript (preprint) (Other academic)
The internal structure of thin current sheets is important for magnetic reconnection and other energy transfer mechanisms, but is not well understood. In this paper we report observations of a high-shear current sheet of width comparable to electron spatial scales, with bifurcated structure embedded within a magnetopause with thickness of several ion-scales. The current sheet has features consistent with guide-field magnetic reconnection close to the electron diffusion region, such as strong out-of-plane currents, Hall electric and magnetic fields, and agyrotropic electron distributions. These distributions have crescent-shaped components due to finite gyroradius effects at the boundary of the current sheet. The crescent distributions carry perpendicular currents with magnitudes comparable to the parallel currents and are thus an integral part of the current system supporting the magnetic field structure. Electrons behave adiabatically in the vicinity of the current sheet where they convect with the magnetic field into the magnetic reconnection inflow region. These results provide an important step forward in understanding magnetic reconnection and the dynamics of electrons within thin electron-scale current sheets.
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:uu:diva-307954OAI: oai:DiVA.org:uu-307954DiVA: diva2:1049009