Last changed in November 2001

Plasma drift/electric field model

The plasma drift/electric field model will provide electrostatic potential patterns and the corresponding electric fields and ExB plasma drifts over the apex magnetic latitude range of 50 degrees through 82 degrees, based on data from the complete Millstone Hill and Sondrestrom ISR databases.

Line of sight Doppler ion drift measurements are used to determine the northward and eastward ion drift components as a function of Apex latitude, local time, and season. The drifts in each of these bins are then fit to the IMF By and Bz values, using the following relationship

V_North = A + B * (By) + C * (Bz)

V_East = D + E * (By) + F * (Bz)

Where A-F are the fit coefficients, and By and Bz are the 15 minute averages of the IMF. The IMF data is corrected to account for propagation from the IMP 8 satellite to the ionoshpere. The plasma drift/electric field model will represent the average response to the solar wind induced changes in the magnetospheric convection, thus providing a baseline from which the more variable effects of substorms and storm, and disturbed neutral wind (the disturbance dynamo) can be isolated [e.g. Foster et al, 1986]. Millstone Hill lies near the equatorward boundary of most convection models, so our plasma drift model, which will include data near and to the south of Millstone, will help specifiy the low-latitude boundary of the magnetospheric convection pattern which is not well represented at present.

Model Status

The preliminary work of binning the data and computing the fit parameters has been completed. Examiniation of the fit parameters for each bin, as well as any necessary smoothing of the parameters between local time and latitude bins remains to be done. For that reason, results from out electric field model are currently unavailable. We have made two movies of the model output, which you can click on below, which show convection changes as one component of the IMF changes. It is evident from these movies that there are some bins for which some tweaking of the parameters is necessary.

There are still a number of modifications which need to be made to the model:

Animated Gifs of selected Model output