Wave-particle Interaction In The Plasmasphere And Associated Influence On The Ionosphere

The energetic particle precipitation caused by wave-particle interaction in the inner magnetosphere is a main particle coupling in the system of the magnetosphere and ionosphere. The research of the characteristics of wave-particle interaction in the plasmasphere and associated influence on the ionosphere is a key project in the coupling of the system between the inner magnetosphere and ionosphere, which is the focus of this thesis.Firstly, with observations of multiple satellites and ground-based instruments during the geomagnetic storm on July 18,2005, the thesis shows the characteristic of wave-particle interaction in the plasmaspheric plume. For the first time, the spatial distribution of the plasma waves in the plasmaspheric plume is revealed, i.e. ELF hiss is located in the vicinity of the electron density peak while electromagnetic ion cyclotron (EMIC) waves are observed in the outer boundary of the plasmaspheric plume. It is also obtained that the in-situ evidence of the ring current ions scattered into the loss cone caused by EMIC waves in the plasmaspheric plume. In addition, during geomagnetic storms the distribution characteristic of energetic particle precipitation due to wave-particle interaction in the plasmaspheric plume has been founded.Consequently, the thesis focuses on the physical mechanism of scattering of energetic ions into the loss cone based on the observations of the Cluster satellite during its passage from the plasma sheet into the inner magnetosphere. The results suggest that energetic ions scattering into the loss cone in the central plasma sheet and the outer boundary of the plasmaspheric plume are attributed to the field line curvature scattering mechanism and EMIC wave scattering mechanism, respectively.Finially, with observations of multiple satellites and ground-based instruments during geomagnetic storms, the thesis shows the influence of the wave-particle interaction in the plasmasphere on the ionosphere. For the first time, the evidence of ionospheric influence of the energetic ion precipitation caused by EMIC waves during geomagnetic storms is obtained. The result demonstrates that energetic ion precipitation caused by EMIC waves during geomagnetic storms can lead to an obvious enhancement of the electron density at the peak height and the conductivities in the E layer. The ionospheric observing signatures of energetic particle precipitation due to wave-particle interaction in the plasmaspheric plumes during geomagnetic storms have also been revealed, i.e. energetic electrons scattered by the plasmaspheric hiss into the loss cone precipitate into the ionospheric D-region, leading to the strong absorption of sounding echoes with lower frequencies for the ionosonde in the storm-enhanced density (SED) plume. On the other hand, the energetic ions scattered by EMIC waves into the loss cone precipitate into the ionospheric E-region, leading to the appearance of Es layer.The results of the thesis are very important to understanding the particle coupling characteristics of the system between the inner magnetosphere and ionosphere and be the guide to ionospheric observations at sub-auroral latitudes.