The development of compression long-period pulsations on the recovery phase of the magnetic storm on May 23, 2007

The features of the excitation of spatially localized long-period (10–15 min) irregular pulsations with a maximum amplitude of ~200 nT at a geomagnetic latitude of 66° in the morning sector 5 MLT are considered. Fluctuations were recorded against the background of substorm disturbances (maximum AE ~ 1278 nT). Antiphase variations of plasma density and magnetic field accompanied by vortex disturbances of the magnetic field both in the magnetosphere and the ionosphere have been recorded in the magnetosphere in this sector. Compression fluctuations corresponding to a slow magnetosonic wave have been recorded in the interplanetary medium in the analyzed period. It is assumed that pulsations have been excited in the localization of the cloud of injected particles in the plasma sheet by compression fluctuations caused by variations of the dynamic pressure of solar wind.