ABSTRACT

In 2000, the extreme ultraviolet (EUV) imager onboard NASA's IMAGE satellite ushered in a new era for the plasmasphere, the relatively dense and cold plasma region at the innermost edge of the Earth's magnetosphere. For decades after its discovery, the plasmasphere was largely believed to be a relatively placid, passive component of the inner magnetosphere-ionosphere system. Starting in 2000, global images obtained by IMAGE EUV began to reveal the critical role of the plasmasphere in the energization and loss of more energetic particle populations such as the ring current and outer radiation belt. Results from IMAGE EUV have also demonstrated that storm-time erosion of the plasmasphere is a significant space weather influence, leading to increased radiation levels and interference with GPS signals used for navigation. Seven years after IMAGE was launched, the new view of the plasmasphere is of a dynamic region intimately connected to the fate of other particle populations.