title: First resolved observations of the demagnetized electron-diffusion region of an astrophysical magnetic-reconnection site.
abstract: Spatially resolved, diagnostic signatures across the X-line and electron-diffusion region (EDR) by the Polar spacecraft are reported at Earth's magnetopause. The X-line traversal has a local electron's skin depth scale. First, resolved EDR profiles are presented with peak electron thermal Mach numbers >1.5, anisotropy >7, calibrated electron agyrotropy >1, and misordered expansion parameters indicative of demagnetization and strong (150 eV) increases in electron temperature. The amplitude and phase of these profiles correlate well with a guide geometry kinetic simulation of collisionless magnetic reconnection. Such high resolution diagnosis has been made possible by data processing techniques that afford an 11-fold reduction in the aliasing time for the electron moments.
authors.affiliation: University of Iowa, Iowa City, Iowa 52442, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Scudder
authors.forename: R D
authors.initials: RD
authors.lastname: Holdaway
authors.forename: W S
authors.initials: WS
authors.lastname: Daughton
authors.forename: H
authors.initials: H
authors.lastname: Karimabadi
authors.forename: V
authors.initials: V
authors.lastname: Roytershteyn
authors.forename: C T
authors.initials: CT
authors.lastname: Russell
authors.forename: J Y
authors.initials: JY
authors.lastname: Lopez