In this paper, the trajectories of equatorial low-energy particles (electrons and protons with energies between 1 and 100 keV) inside the plasmasphere (L=1.5--4.5) have been computed for an average quiet dynamo-electric field model that is deduced by incoherent scatter radar observations. It is concluded that electrons tend to corotate with the Earth. On the other hand, protons show a more complex dynamical behavior, strongly depending on energy and local time, presenting open orbits similar to those of electrons, except for an L-dependent energy interval in which closed orbits are found to exist within certain local time intervals. ¿American Geophysical Union 1987