ON THE POSITION OF THE NEAR-EARTH NEUTRAL SHEET - A COMPARISON OF MAGNETIC MODEL PREDICTIONS WITH EMPIRICAL FORMULAS

A detailed comparison of the near-Earth neutral sheet position according to several approximations has been made. In particular, two empirical formulas for the neutral sheet location, recently derived from AMPTE/CCE data, have been compared with the corresponding positions derived from Tsyganenko's magnetic field models. Cylindrical coordinates referenced to the geodipole have been used, and the position of the neutral sheet has been identified by the reversal of the radial component of the magnetic field. The analysis reveals that in the region -9 R(E) less-than-or-equal-to X(GSM) less-than-or-equal-to -5 R(E), \Y(GSM)\ less-than-or-equal-to 5 R(E), close agreement exists between the empirical formulas and the Tsyganenko models. Furthermore, the Tsyganenko models provide a representation for the neutral sheet position in the transition region between near-Earth and distant tail models.