Journal article
Van Allen Probes observation of localized drift resonance between poloidal mode ultra‐low frequency waves and 60 keV electrons
Geophysical research letters, Vol.40(17), pp.4491-4497
09/16/2013
DOI: 10.1002/grl.50901
Abstract
We present NASA Van Allen Probes observations of wave‐particle interactions between magnetospheric ultra‐low frequency (ULF) waves and energetic electrons (20–500 keV) on 31 October 2012. The ULF waves are identified as the fundamental poloidal mode oscillation and are excited following an interplanetary shock impact on the magnetosphere. Large amplitude modulations in energetic electron flux are observed at the same period (≈ 3 min) as the ULF waves and are consistent with a drift‐resonant interaction. The azimuthal mode number of the interacting wave is estimated from the electron measurements to be ~40, based on an assumed symmetric drift resonance. The drift‐resonant interaction is observed to be localized and occur over 5–6 wave cycles, demonstrating peak electron flux modulations at energies ~60 keV. Our observation clearly shows electron drift resonance with the fundamental poloidal mode, the energy dependence of the amplitude and phase of the electron flux modulations providing strong evidence for such an interaction. Significantly, the observation highlights the importance of localized wave‐particle interactions for understanding energetic particle dynamics in the inner magnetosphere, through the intermediary of ULF waves.
Key Points
First conclusive evidence of electron drift‐resonance with poloidal ULF waves.
First to show the energy dependence to the amplitude/phase expected from theory.
Observation shows the drift‐resonant interaction occurs over a localized region.
Details
- Title: Subtitle
- Van Allen Probes observation of localized drift resonance between poloidal mode ultra‐low frequency waves and 60 keV electrons
- Creators
- S. G Claudepierre - The Aerospace CorporationI. R Mann - University of AlbertaK Takahashi - Johns Hopkins UniversityJ. F Fennell - The Aerospace CorporationM. K Hudson - Dartmouth CollegeJ. B Blake - The Aerospace CorporationJ. L Roeder - The Aerospace CorporationJ. H Clemmons - The Aerospace CorporationH. E Spence - University of New HampshireG. D Reeves - Los Alamos National LaboratoryD N Baker - University of Colorado BoulderH. O Funsten - Los Alamos National LaboratoryR H W Friedel - Los Alamos National LaboratoryM. G Henderson - Los Alamos National LaboratoryC. A Kletzing - University of IowaW. S Kurth - University of IowaR. J MacDowall - Goddard Space Flight CenterC. W Smith - University of New HampshireJ. R Wygant - University of Minnesota
- Resource Type
- Journal article
- Publication Details
- Geophysical research letters, Vol.40(17), pp.4491-4497
- DOI
- 10.1002/grl.50901
- ISSN
- 0094-8276
- eISSN
- 1944-8007
- Number of pages
- 7
- Language
- English
- Date published
- 09/16/2013
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199720402771
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