OBSERVATIONS OF PC 1-2 WAVES IN THE OUTER MAGNETOSPHERE

High time resolution measurements made inside the magnetopause from L equals 7 to L equals 14 by the University of California at Los Angeles fluxgate magnetometer aboard the Ogo 5 satellite demonstrate that Pc 1-2 magnetic field oscillations are occasionally present in portions of the outer magnetosphere. Eleven events have been studied so far, and all of them occurred in the afternoon sector at geomagnetic latitudes from 0 degree to plus or minus 30 degree . Both the solar wind dynamic pressure and the magnetospheric cold plasma density were enhanced during events for which the respective data were available. The data within the magnetosphere suggest that the observed pulsations were ion cyclotron waves generated at the geomagnetic equator at large radial distances.