Response of Day-Side Geomagnetic Field to the Northward Turning of IMF Bz

Johns Hopkins University, Baltimore MD

Investigators

Abstract

This project will examine the possibility of using ground-based magnetic field measurements near the magnetic equator to determine when a change in the interplanetary magnetic field (IMF) orientation hits Earth's magnetopause. Knowing exactly when an IMF polarity change hits the magnetopause is important for understanding the exact timing of events related to the initiation of a magnetic substorm. Currently there is no reliable way of knowing exactly when the polarity change encounters the magnetosphere because the only direct measurements are made by spacecraft located in the solar wind upstream from the magnetopause. Models for the propagation of the observed IMF from the spacecraft position to Earth are very inexact and potentially error prone. If the proposed method of using the equatorial electrojet can be demonstrated to be a robust method of determining the actual impact of the IMF on the magnetosphere the method has the potential to transform the way IMF controled phenomena are investigated. This would have significant impacts on our ability to specify space weather conditions.