The Geotail satellite detected a filament of tailward-streaming energetic particles spatially separated from the boundary layer of energetic particles at the high-latitude dawn magnetopause at a downstream distance of ~80 RE on October 27, 1992. During this event, the composition and charge states of energetic ions at energies above ~10 keV show significant intermix of ions from solar wind and ionospheric sources. Detailed analysis leads to the deduction that the filament was moving southward towards the neutral sheet at an average speed of ~80 km/s, implying an average dusk electric field of ~1 mV/m. Its north-south dimension was ~1 RE and it was associated with an earthward-directed field-aligned current of ~5 mA/m. The filament was separated from the energetic particle boundary layer straddling the magnetopause by ~0.8 RE and was inferred to be detached from the boundary layer at a downstream distance beyond ~70 RE in the distant tail. ¿American Geophysical Union 1994