Why We Need Global Observations

Abstract

Since its initiation with the remarkable discovery of the Van Allen radiation belts, the field of magnetospheric physics has been characterized by a continuing collection of data from in-situ satellite observing stations. The synthesis of these and ground-based observations has yielded an intriguing picture of a basic cosmological building block, the magnetosphere. Because of the time/space separation inherent in magnetospheric observations, this view necessarily is schematic in nature and our knowledge of global behavior is correspondingly incomplete. Since both local and global perspectives must be combined to understand such a complex physical system, the lack of appropriate global magnetospheric observations represents a serious impediment towards obtaining an understanding of magnetospheric dynamics. From the use of ground-based station networks to the advent of satellite auroral images, the drive for global knowledge has been relentless and has always delivered new and unexpected perspectives of the structures and phenomena being studied. This need for an overall perspective has brought us to the point of now being able to globally image the particle populations of the magnetosphere. This, combined with existing large-scale observations, provides for the first time, the capability of observing the magnetosphere on a global basis. We expect that when this capability is realized, our concepts of the magnetosphere will be altered every bit as dramatically as Professor Van Allen’s discovery of the radiation belts changed our view of the space environment.