butterfly pitch angle distributions

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)
Ni, B., Zou, Z., Fu, S., Cao, X., Gu, X., & Xiang, Z. (2018). Resonant Scattering of Radiation Belt Electrons by Off-Equatorial Magnetosonic Waves. Geophysical Research Letters, 1228-1236. http://doi.org/10.1002/grl.v45.310.1002/2017GL075788 (Original work published February 2018)