| Popis: |
Convection electric fields, E{sub c} = {minus}V{sub p}{times}B, measured during a magnetopause/boundary layer encounter at low latitude by the AMPTE/IRM spacecraft, are shown to yield an accurate determination of the magnetopause normal vector, N, even though the magnetic shear across the magnetopause was small. The average plasma velocity along N is used to deduce a boundary layer thickness of about 1.3 R{sub E}. Analysis of E{sub c} in the magnetopause itself reveals the existence of a deHoffmann-Teller frame in which the flow is nearly field aligned and approximately Alfvenic, indicating that the magnetopause was a rotational discontinuity; this is interpreted as a signature that magnetic-field reconnection was occurring somewhere on the magnetopause. |
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