Estimation of electric fields and currents from international magnetospheric study magnetometer data for the CDAW 6 intervals: Implications for substorm dynamics

Publisher Website
Google Scholar
Abstract
Using a recently developed numerical scheme combined with International Magnetospheric Study magnetometer data and the Rice University ionospheric conductivity model as input, the global distribution of the key ionospheric parameters is estimated for the Coordinated Data Analysis Workshop (CDAW) 6 intervals. These outputs include ionospheric electric fields and currents, field‐aligned currents and Joule heat production rate at high latitudes, and are compiled in the form of a color movie film, which demonstrates dynamics of substorm changes of the three‐dimensional current system as well as of the associated potential pattern. The present paper gives, on the basis of the space‐time distribution of the key parameters, the substorm time frame that can be referenced to in terms of the substorm phases when discussing some other magnetospheric and ionospheric records. The distinction between “substorm expansion” and “enhanced convection” current systems is presented on the basis of the conventional equivalent current and potential patterns and “true” ionospheric currents. Although the auroral electrojets flow rather contiguously throughout the dark sector, there are several separate source regions of Joule heating from the electrojet currents. This indicates that the relative importance of the ionospheric conductivity and the electric field in the ionospheric currents varies considerably depending upon latitude and local time. A possible difference in the generation mechanisms of isolated and continuous substorm activity is also discussed to some extent in the light of the two CDAW 6 intervals.

This publication has 29 references indexed in Scilit: