On nonlinear displacement of the latitude profile of Pc5 geomagnetic pulsations

A pronounced discrepancy exists between the theory, which definitely indicates that magnetospheric oscillations are anharmonic, and the experimental study of geomagnetic pulsations. This paper raises a question about experimental study of the nonlinearity of Pc5 pulsation amplitude latitude profile (the period range is 150-600 s). To search for non-linear distortions of the profile, we used Pc5 observation data from the meridian chain of stations IMAGE. A specific event was analysed to show the northward displacement of peak Pc5 amplitude along the meridian with decreasing oscillation amplitude. The measurement findings allowed us to determine coefficient of non-linear distortions in the latitude profile. The main conclusion is that the anharmonicity of geomagnetic pulsations can be studied by experiment.