NASA Goddard Space Flight Center
The Earth's Dynamical Radiation Belts: Recent results from the Van Allen Probes mission
The Earth's radiation belts first discovered by James Van Allen and named after him, comprise charged particles trapped in the geomagnetic field. There are two belts separated by the so-called slot region. The outer belt contains chiefly electrons whose intensities are highly variable, being affected by multiple processes of energization and loss. These processes include radial transport, and wave-particle interactions. The study of these processes is interesting not only scientifically but also has practical consequences since high intensities of energetic particles can adversely affect spacecraft and humans in space.
The Van Allen Probes, a major NASA mission was launched late August 2012 to study the radiation belts in a comprehensive manner. The mission which operated until Summer-Fall of 2019, comprised two identically instrumented spacecraft carrying a comprehensive suite of instruments that characterize charged particles, electric and magnetic fields, and plasma waves in the Earth's radiation belts. In particular, the ECT suite of instruments comprising of HOPE, MagEIS and REPT instruments measure electrons, protons and ions and their angular distributions over energies ranging from a few eV to several tens of MeV. Measurements from Van Allen Probes have made significant and paradigm-shifting contributions towards the understanding of the physics of charged particles in the Earth's radiation belts.
I will describe the Van Allen Probes mission emphasizing the ECT instrument suite and present some of the significant science results pertaining to the dynamics of electron energization and loss in the outer radiation belt.