On 26 August 1982 the satellites Dynamics Explorer 2 (DE-2) and Aureol-3 (A-3) crossed around the same time the southern polar cusp. DE-2 detected the cleft in the prenoon sector (11.5 H MLT) constituted by a poleward ion dispersion with two steps at around 50 and 1.5 keV, respectively. Around 1.5 H MLT eastward, A-3 detected a diffuse ion precipitation, immediately followed by an equatorward dispersion (energy increases when the latitude increases). The convection pattern detected by DE-2 was directed westward in the cleft with a maximum, around 1600 m/s, centred on the low energy step. The convection velocity measured by A-3 had a component directed poleward where the diffuse ion precipitation was observed and a convection with an equatorward component where the ion dispersion is observed. The IMP-8 IMF data showed a gap at the time of the cusp crossings, however using the IMF-Bz component around that time and the AE index we infer that the IMF-Bz would have been positive during the cusp crossings. We are explaining the observations by the merging of the interplanetary magnetic field with the geomagnetic lobe field lines which produces the dispersion observed at high latitude on A-3 and the low energy step observed by DE-2. At the same time a viscous diffusion on the frontside of the magnetosphere produces the diffuse ion precipitation observed by A-3 and the high energy step observed by DE-2.¿ 1997 American Geophysical Union