Radial Transport of Higher-Energy Oxygen Ions Into the Deep Inner Magnetosphere Observed by Van Allen Probes

Author
Keywords
Abstract
The transport mechanism of the ring current ions differs among ion energies. Lower-energy (≲150 keV) ions are well known to be transported convectively. Higher-energy (≳150 keV) protons are reported to be transported diffusively, while there are few reports about transport of higher-energy oxygen ions. We report the radial transport of higher-energy oxygen ions into the deep inner magnetosphere during the late main phase of the magnetic storm on 23\textendash25 April 2013 observed by the Van Allen Probes spacecraft. An enhancement of 1\textendash100 mHz magnetic fluctuations is simultaneously observed. Observations of 3 and 30 mHz geomagnetic pulsations indicate the azimuthal mode number is <=10. The fluctuations can resonate with the drift and bounce motions of the oxygen ions. The results suggest that the combination of the drift and drift-bounce resonances is responsible for the radial transport of higher-energy oxygen ions.
Year of Publication
2018
Journal
Geophysical Research Letters
Date Published
05/2018
URL
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL077500
DOI
10.1029/2018GL077500