Periods of the Magnetospheric Oscillations and the Plasma Density

Using the model magnetosphere of the Mead's type, periods of self oscillation of the magntosphere are calculated for the cases of weak or strong dependence of its amplitude on longitude. It is shown that the transverse wave can exist when the periods of these two modes are equal. This condition is satisfied at latitudes near the auroral zone. The oscillations with a longitudinal dependence in form of Gauss-function are also considered, and the values of Ne/T2 are calculated. The plasma density Ne in the magnetosphere is estimated using the period T of observed geomagnetic pulsations; the result is in agreement with the data of other methods.