A nonlinear displacement of Pc5 latitudinal profiles

A pronounced difference exists between the theory, which definitely indicates that magnetospheric oscillations are anharmonic, and the experimental study of geomagnetic pulsations. The experimental study of the nonlinearity of the Pc5 pulsation amplitude latitudinal profile (the range of periods is 150–600 s) is considered. The Pc5 registrations at the IMAGE meridional chain of station were used to search for nonlinear distortions of the profile. Using a specific event, it has been indicated that the Pc5 amplitude peak shifts northward along the meridian with decreasing oscillation amplitude. The coefficient of nonlinear distortions in the latitudinal profile has been determined based on the measurements. The main conclusion consists in that a delicate problem of geomagnetic pulsation anharmonicity can be entirely studied experimentally.