Persistent Pitch Angle Anisotropies of Relativistic Electrons in the Outer Radiation Belts

A. D. Greeley*, S. G. Kanekal, Quintin Schiller, Lauren Blum, Alexa J. Halford, Kyle Robert Murphy, Tero Raita, Daniel N. Baker

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Pitch angle distributions (PADs) in the radiation belts are well characterized with sinn(α). By tracking the exponent “n,” termed pitch angle index, we are able to observe persistent and cross-energy changes in PADs of Van Allen radiation belt electrons using Van Allen Probes particle observations. The PAD measurements are well fit down to a single satellite spin, and therefore can track spatially and temporally confined changes to determine the connection between particles and waves. With this method, we study long-lasting and high-energy anisotropic electron PADs during a quiet period over 2 days, 26 and 27 June 2013. One potential driver for these changes is electromagnetic ion cyclotron wave interaction with the particles. We use several ground magnetometer stations from Canadian Array for Realtime Investigations of Magnetic Activity and Finnish pulsation magnetometer network of Sodankylä Geophysical Observatory to observe waves during the 2 days of interest. The connection between the waves and particles is inconclusive, although there is some temporal overlap of the phenomenon.

Original languageEnglish
Article numbere2023JA031549
Number of pages15
JournalJournal of Geophysical Research: Space Physics
Issue number1
Early online date26 Dec 2023
Publication statusPublished - 1 Jan 2024
Externally publishedYes

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