DC polarization electric field, current density, and plasma density measurements in the daytime equatorial electrojet

Abstract

Measurements of the vector DC electric field, current density, and plasma number density were gathered in the daytime equatorial electrojet on a sounding rocket launched from Alcântara, Brazil. The data set provides a self‐consistent picture of the electrodynamics of the daytime electrojet, permitting a detailed comparison of the altitude profiles of the vertical component of the DC electric field, E vert , the current density, J, and the plasma number density, N e . Good agreement in the upper electrojet region between both the magnitude and the profile of the plasma drifts, calculated independently from E vert /B and J zonal /qN e , demonstrates that the equatorial electrojet is a Hall current consisting of electron motion driven by a vertical DC electric field. The data support the basic Cowling conductivity ideas of electron flow at the dip equator within a narrow conducting layer in which the ions are at rest.