Spatial Structure of Simultaneous Magnetic and Riometer Ðñ5 Pulsations

Several events with intense Pc5 pulsations at the recovery phase of a magnetic storm are considered in detail. A global structure of disturbance is studied with the data from world-wide array of magnetometers and riometers augmented with the data from particle detectors and magnetometers at the geosynchronous orbit. A local spatial structure is examined using the Finnish riometer array and IMAGE magnetometers. Though a general similarity between the quasi-periodic magnetic and riometer variations is observed, their local propagation patterns turned out to be different. To interpret the observations, the hypothesis of the coupling between two oscillatory systems - magnetospheric Alfven resonator and the system turbulence + electrons, has been suggested. The comparison of energetic electron enhancements at LANL satellites and ULF activity demonstrates that the solar wind flow is not the only driver of magnetospheric Pc5 pulsations, but the wave generation is stimulated by electron injection.