INTERNAL CONSISTENCY OF THE TSYGANENKO MAGNETIC-FIELD MODEL AND THE HEPPNER-MAYNARD EMPIRICAL-MODEL OF THE IONOSPHERIC ELECTRIC-FIELD DISTRIBUTION

We use the Tsyganenko [1987; 1989] magnetic field models to map the electric field distribution of Heppner and Maynard [1987] into the geomagnetic tail and infer the velocity of the CPS convective flow. We obtain qualitatively different convection patterns from the two Tsyganenko models. Results obtained with the 1987 model predict a narrow jet of earthward moving plasma in the center of the CPS, while the 1989 model predicts relatively uniform earthward convection throughout the CPS. Based on in situ observations of CPS convection, we conclude that the 1989 model provides the most realistic mapping. We also suggest that the effects of field-aligned currents should be incorporated into the magnetic field models to improve the mapping.