Study Of Structure And Kinetic Propcesses Of Boundaries In The Earth's Magnetosphere Using Satellite Observation

The Earth's Magnetosphere is one of the most important areas in the solar-terrestrial physics. Equilibria between plasmas of different properties often give rise to the formation of boundaries separating the two adjacent plasma regions in the earth's magnetosphere. Studying these boundaries could be significantly important for us to further understand various physical phenomenon of magnetosphere (e.g. magnetic reconnection) and the coupling between various regions of the magnetosphere. The study of wave-particle interactions in the boundaries of magnetosphere plays an important role in revealing the mechanism of energy release and transition in the magnetosphere.In this thesis, we utilize the observation data of the Cluster-Ⅱand the THEMIS spacecrafts, studying the structures and kinetic processes of boundary layers with different scales in different regions of the Earth's magnetosphere. The main results are listed as below:1, We studied the structure and kinetic properties of slow-mode shocks near the plasma sheet boundary layer (PSBL) associated with magnetic reconnection by Cluster observation. The presence of slow-mode shocks is confirmed by traditional Rankine-Hugoniot (RH) analysis and Monte-Carlo shock fitting method. The Walen analysis, applied to the tailward flow associated with slow-mode shocks, also supports that plasma was accelerated across a Petschek-type slow-mode shock connected to the diffusion region. Back-streaming ions were observed on the shock layer, and cold ions were accelerated and heated by slow-mode shocks. In addition, whistler and electrostatic solitary waves were observed around the slow-mode shocks. These waves might be excited by the observed field-aligned electron beams near the shocks. 2, We investigated the structure of double layers (DLs) near the bow shock by the THEMIS observations during several bow shock crossings. We report the first direct observations of parallel electric fields carried by double layers in the transition layer of bow shock. The parallel electric fields carried by DLs are associated with strong turbulence in the form of electron phase-space holes. The amplitude of the parallel electric fields (E//) carried by double layers is between-45-90mV/m. The potential change due to parallel electric fields (E//) carried by double layers is between～70-180V. The parallel size of the E//structure ranges from-90λD to～160λD, whereλD is the local debye length. The signatures of DLs observed in the transition layer of bow shock are analogous to those reported in the experimental plasma. Observation of DLs in the bow shock sheds new light on the understanding of wave-particle interaction and energy dissipation in the bow shock.3, We investigated the wave characteristics in the transition layer and the downstream region of bow shock by the THEMIS observation. There were strong magnetic fluctuations in the transition layer and the downstream region of the bow shock. The main waves were whistler waves and electrostatic solitary waves. Abundant ESWs were observed in the transition layer, associated with double layers. The characteristics of ESWs are:a) pulse width:the pulse interval of ESWs were longer than the corresponding pulse lengths, indicating that the ESWs were highly isolated; b) amplitude:the amplitude of ESWs in the transition layer of bow shock could reach several hundreds mV/m; c) structure:various types of two-dimensional ESWs were observed in the trasition region of bow shock.4, We observed many DLs in the Earth's magnetosphere by using high-resolution data of the THEMIS satellites. These DLs are primarily observed at the PSBL when there were strong magnetic field fluctuations. The amplitude of the parallel electric fields (E//) carried by double layers is between～4-60mV/m. The potential change across the DLs is between～40-1430 V. The scale size of the DLs ranges from～5λD to～65λD。...