On October 24, 1984, the AMPTE/IRM satellite, on its inbound orbit in the 1300 LT sector, observed a strong compressional Pc 5 event lasting for about an hour. The use of data from the full complement of detectors aboard the spacecraft (magnetometer, three-dimensional plasma instrument, wave experiment, and SULEICA time-of-flight analyzer including its electron sensor package) allowed for detailed measurements of field and particle oscillations, with the latter covering energies from a few electron volts up to tens of keV (electrons) or even 1 MeV (protons). Both energetic proton and electron fluxes were anticorrelated with the compressional magnetic field oscillations, indicating that the event belongs to the class of ''in-phase events.'' But the energetic proton data also exhibited a new feature; Flux minima and maxima at low energies were observed somewhat later than those at higher energies (with time differences of ~2 min between 3 and 40 keV). The magnetic and plasma pressure oscillations satisfy the pressure balance equation for the drift mirror mode much better than that for drift compressional Alfv¿n waves. However, the classical criterion for the onset of the mirror instability is not satisfied. The low-energy particles showed clear signatures of gradient convection due to the wave electric field with the protons additionally undergoing gyration acceleration. The period of the pulsation decreased while the satellite was moving inward, in agreement with the individual L shell resonance model. But in contrast to earlier observations the periods of the compressional and transverse oscillations differed significantly (by ~25%). We interpret this as Doppler shift due to spacecraft motion since in the present event the transverse oscillations did not have the purely radial (poloidal) polarization common to other published cases. They had an additional azimuthal (toroidal) component, making it likely that the wave fronts of compressional and transverse oscillations were inclined with respect to each other. ¿ American Geophysical Union 1987