Geomagnetism

Equatorial Electrojet Model EEJM2

The Equatorial Electrojet (EEJ) is an intense electric current flowing along the magnetic equator in the E-region of the ionosphere. Six years of satellite magnetic measurements from the CHAMP, Oersted and SAC-C satellites have provided an unprecedented longitudinal coverage of the EEJ magnetic signature. This model is a result of inverting the magnetic signature for the current density and then fitting the observed currents. The model provides the climatological mean and variance of the EEJ as a function of longitude, local-time, season, solar flux, and lunar local-time. There are three separate models included in the package below - one for each of the three satellites. The driver program defaults to using the CHAMP model, since due to its lower altitude it can more easily resolve the peaks in the EEJ magnetic signature, and therefore the resulting CHAMP data is of higher quality than the other two satellites. The user can easily specify one of the other two satellites to use when running the driver program (see the README file). Below we give some sample plot outputs from the model. Updated version 2.0 now allows for differences between spring and fall equinox, in addition to a lunar local-time dependence.

Fig. 1: Plots of the EEJ current density as a function of longitude and local-time from the CHAMP satellite data.

Available EEJM2 Downloads
	Type	Format	Mbyte	Contents
	Model (driver and coefficients)	tar/gz	0.3	EEJM2 Model driver program source code and coefficients
	Model (driver and coefficients)	zip	0.3	EEJM1 Model driver program source code, coefficients, and windows executable
	Article	PDF	0.3	Spatio-temporal characterization of the equatorial electrojet from CHAMP, Oersted, and SAC-C satellite magnetic measurements (preprint)

Patrick Alken