global occurrence pattern

Ni, B., Zou, Z., Li, X., Bortnik, J., Xie, L., & Gu, X. (2016). Occurrence Characteristics of Outer Zone Relativistic Electron Butterfly Distribution: A Survey of Van Allen Probes REPT Measurements. Geophysical Research Letters. http://doi.org/10.1002/2016GL069350 (Original work published May 2016)