This paper explores some possibilities for plasma populations, field-aligned currents, and field-aligned potentials in the magnetosphere of Neptune. Observed plasma populations at Saturn and Uranus may provide reasonable upper and low limits, respectively, to those at Netpune. Field-aligned current densities comparable to those at Earth may be observed by the Voyager magnetometer above Neptune's auroral zone. Inverted-V events reaching energies of several tens of keV may also be observed by the Voyager Low Energy Charged particle experiment. ¿ American Geophysical Union 1989