Space Science Reviews

, Volume 173, Issue 1, pp 103-131

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Acceleration of Particles to High Energies in Earth’s Radiation Belts

  • R. M. MillanAffiliated withDepartment of Physics and Astronomy, Dartmouth College Email author 
  • , D. N. BakerAffiliated withLaboratory for Atmospheric and Space Physics, and Department of Physics, and Department of Astrophysical and Planetary Sciences, University of Colorado


Discovered in 1958, Earth’s radiation belts persist in being mysterious and unpredictable. This highly dynamic region of near-Earth space provides an important natural laboratory for studying the physics of particle acceleration. Despite the proximity of the radiation belts to Earth, many questions remain about the mechanisms responsible for rapidly energizing particles to relativistic energies there. The importance of understanding the radiation belts continues to grow as society becomes increasingly dependent on spacecraft for navigation, weather forecasting, and more. We review the historical underpinning and observational basis for our current understanding of particle acceleration in the radiation belts.


Particle acceleration Radiation belts Magnetosphere