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MPIS_PROJECTS:
Cluster
MPIS_PROJECTS:
Cluster: CIS
Abstract:
A chain of events accompanying the occurrence of a substorm in the Earth’s ionosphere and magnetosphere is considered. Features of geomagnetic pulsations and mechanisms of their generation are indicated. Measurements of magnetic field fluctuations from fluxgate magnetometers, as well as the data on temperature, velocity, and concentration of electrons, and different types of ions from the PEACE and CIS-CODIF experiments of the Cluster-2 space mission, have been analyzed. It was found that a significant increase in temperature, velocity fluctuations, and concentration is observed during the initiation of a substorm that was accompanied by dipolarization (sharp change in the magnetic field configuration from the elongated tail-like force lines to a more dipole structure). A time delay in the heating of protons and oxygen ions, as well as in the concentration variations, was detected. The comparison of wave characteristics for different pressures was carried out using wavelet analysis. The magnetic field pressure, as well as dynamic and thermal pressure for different types of particles, was considered. Pc5 and strong Pc4 pulsations, as well as direct and inverse cascades, were observed in the fluctuations of the magnetic field pressure and thermal pressure of electrons and protons. The results point to a significant role of kinetic effects in the complex chain of processes in the Earth’s magnetosphere during the explosive phase of a substorm.
