The radial mode structure of Pi2 pulsations in the inner magnetosphere (L 3.5 it was also possible to determine the amplitude and phase of the compressional component Bz at CRRES. In contrast to Eϕ, the phase of Bz (relative to H) was clustered both at ~180¿ and ~0 for events occurring near the plasmapause. This observation still is consistent with the cavity mode according to a numerical simulation using a dipole magnetic field and a realistic plasmapause plasma density structure, which indicates that the node of Bz is located near the plasmapause. Depending on the satellite position relative to the node, the phase can be either --180¿ or 0. A negative correlation is found between the Pi2 frequency and the distance of the plasmapause, which is additional support for the cavity mode origin of low-latitude Pi2 pulsations.