An approximate relation between energy and equatorial radial distance for a particle of pitch angle &agr;eq moving adiabatically in a dipole magnetic field is used to describe the Alfv¿n layer for particles of arbitrary pitch angle. The convection electric field is assumed to be uniform in the equatorial plane of the magnetosphere, and magnetic field lines are taken to be equipotentials in the region traversed by the magnetospheric particles being studied. Approximate solutions in the high- and low-energy limits are given in a form directly applicable to the interpretation of measurements at fixed particle energy and pitch angle. These results are particularly useful for electrons, since the approximations provide lower bounds to the exact solutions. The results are used to ins are used to interpret recent Explorer 45 electron measurements of Williams et al. a second prominent time of occurrence of extreme negative H values came at