Study Of The Distribution Of Plasma Wave Characteristics In The Earth's Magnetosphere

Plasma waves are commonly found in the Earth's magnetosphere in frequency ranges spanning multiple orders of magnitude.The most common types of waves include ultralow frequency(ULF)waves distributed throughout the magnetosphere,as well as extremely low frequency(ELF)and very low frequency(VLF)waves in the inner magnetosphere,such as hiss wave,chorus wave,magnetosonic wave,and electromagnetic ion cyclotron wave.The energy of these waves mainly originates from the plasma instabilities(e.g.pitch angle anisotropy and bimodal distribution),which generated from the coupling process between the solar wind and the magnetosphere.Since the plasma in the magnetosphere is collisionless,waves in the magnetosphere as a medium for collective interactions of plasma can profoundly affect the dynamical processes in the magnetosphere,and therefore of significant research value.Energy can be transferred between charged particles and waves through wave-particle interactions,affecting the phase space distribution of particles and their evolutionary processes.Plasma waves can also transfer energy among different regions of the magnetosphere,which has an important impact on space weather.The launch of satellite missions such as THEMIS and Van Allen Probes has made it possible to systematically study the global distribution of wave properties in the magnetosphere,which is important for our deeper understanding of the coupling processes between the solar wind,magnetosphere,and ionosphere.In the first chapter,we give a brief overview of the structure of the Earth's magnetosphere and three adiabatic invariants,followed by a detailed review of the general characteristics and global distribution of three common types of waves in the magnetosphere(ultralow frequency wave,chorus wave,and hiss wave),and present the problem to be addressed in this thesis.In the second chapter,we present a statistical analysis of the global distribution of ULF wave properties in the magnetotail region using data from THEMIS mission.Previous studies on the ULF waves distribution mainly focused on the dayside and near-Earth regions.Although some observational and simulation studies have reported the characteristics of ULF waves on stretched magnetic lines in the magnetotail,the distribution and excitation mechanism of ULF waves on stretched magnetic lines are still unclear due to the lack of statistical studies.In this chapter,using THEMIS satellite data during the period from 2008 to 2015,the Pc5-6 ULF waves in the tail region with XGSM<0,8RE