All Physics Faculty Publications

Document Type

Article

Journal/Book Title/Conference

Journal of Geophysical Research

Volume

79

Issue

31

Publication Date

1974

First Page

4669

Last Page

4678

DOI

10.1029/JA079i031p04669

Abstract

In this paper we describe the results of a series of geomagnetic meridian plane radar incoherent scatter plasma transport measurements. From such data the eastward (zonal) component of the electric field can be deduced. The results show that the electric field has an eastward component whenever the discrete auroras are northward of the region of the measurement. The zonal field component turns westward as the discrete auroras move equatorward of the region of the measurement. Thus there is an eastward electric field boundary near the equatorward limit of the discrete aurora, which is the poleward boundary of the diffuse aurora during undisturbed periods. During a particularly disturbed period we also observed three pronounced substorm-related enhancements of the westward-directed zonal field. For midnight and morning sector substorms the enhancements preceded the substorm onset times by 20-30 min. We show from meridian chain all-sky camera data that all three enhancements coincided with equatorward expansions of the auroral oval.

Comments

Published by American Geophysical Union in Journal of Geophysical Research Space Physics. Publisher PDF available for download through link above.