Measurements of Energetic Particles in the Radiation Belts

Abstract

The techniques for the measurement of plasma and energetic particles in the near-Earth space environment have evolved rapidly since the advent of the space age about 50 years ago. Since then hundreds of different techniques have been developed, optimised for different energy ranges and types of particles as, for example, electrons and ions. This instrumentation is based on well known physical principles, first used in instruments for e.g. laboratory plasma physics or high-energy particle accelerators. However, because of the stringent constraints on mass and power that could be accommodated onboard space missions, it took a long time to develop the technology that made the implementation of these techniques onboard satellites possible. This review provides an overview of some of the basic techniques for the determination of plasma parameters and the measurement of the energetic particle population in space. Most of the techniques used so far determine the particle distributions by in situ measurement of the particle parameters velocity, mass, and ionic charge. However, to obtain a more global perspective of the near-Earth environment either remote sensing techniques or multi-spacecraft missions with simultaneous in situ measurements onboard a large number of spacecraft are needed.