Particle Acceleration in Near Earth Geospace

The radiation belts occupy a vast region of near Earth geospace where many important communication, navigation, Earth observation, and defence satellites operate. In recent decades, demand for space technology has grown dramatically and this is set to grow further as humans become more and more dependent on space technology. Without the operation of currently hundreds of satellites around the Earth, the world would face a huge catastrophe to support a population of 7 billion plus. Trapped energetic radiation belt electrons represent a serious hazard to spacecraft electronic components. At the geostationary orbit, which is located at the edge of the outer radiation belt, these highly energetic electrons are accelerated to high energies, in the range of keV to MeV, through various processes. Therefore, it is considerably important to understand the basic properties of the Van Allen radiation belts and the main processes that are thought to be important in the acceleration and loss mechanisms of the radiation belt electrons that ultimately change the dynamics of the radiation belts. This thesis investigates particle acceleration in near Earth geospace. The findings of this research expanded our knowledge of the Van Allen radiation belts through studying the relationship between solar wind parameters and energetic electron fluxes at the outer radiation belt, the study of naturally occurring electromagnetic waves and their crucial role in the acceleration and loss of energetic electrons in the inner magnetosphere, and the study of particle acceleration in the vicinity of the Earth and interplanetary medium by strong interplanetary collisionless shocks associated with Coronal Mass Ejection (CME), in particular, in the case of strong collisionless shock formation associated with shock coalescence. The results can be used to help improve forecasting and nowcasting of changes in energetic electron population and ultimately help mitigate the damage caused to the satellites and other space based systems. Subsequently, this would help increase satellite lifetime and improve reliability.