A long-lasting Pc 5 pulsation at the dawn flank of the magnetosphere is studied using particle and field instrumentation from the ISEE 1 and 2 satellites. Electric field and particle modulation signatures were clearer than magnetic field variations, consistent with the satellites' position in latitude near the equatorial node of a fundamental resonance. Pulsation flow velocities along the ISEE 1 trajectory were calculated from particle characteristics using data from several instruments and from electric and magnetic field data. These flow velocities were all consistent with each other, but the velocities derived from plasma and energetic particle observations were a factor of 2.5 larger than velocities derived from the fields data. We have not been able to find the source of this discrepancy; one possibility is that the field near the spacecraft differs from the large-scale field. In contrast to observations of pulsations during magnetic storms, which often involve resonant or gyrating particle behavior, particles at all energies sampled (10 eV to 200 keV) appeared to respond passively to the pulsation throughout most of the period of interest. Comparison of data from the two spacecraft, which traveled from ~15 RE to ~7 RE with a time separation of ~1 hour, suggests the propagation of relatively broadband pulsation energy from the magnetopause/low latitude boundary layer and subsequent resonance of independent L shells in the fundamental toroidal mode after the cessation of power input. ¿ American Geophysical Union 1990