Low-energy (< 200 eV) electron acceleration by ULF waves in the plasmaspheric boundary layer: Van Allen Probes observation
- Peking Univ., Beijing (China); Nagoya Univ., Nagoya (Japan)
- Peking Univ., Beijing (China)
- Nagoya Univ., Nagoya (Japan)
- Univ. of Alberta, Edmonton, AB (Canada)
- UCLA, Los Angeles, CA (United State); Univ. Corp. for Atmospheric Research, Boulder, CO (United States)
- Univ. of New Hampshire, Durham, NH (United States)
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Univ. of Minnesota, Minneapolis, MN (United States)
- Univ. of Iowa, Iowa City, IA (United States)
Here, we report observational evidence of cold plamsmaspheric electron (< 200 eV) acceleration by ultra-low-frequency (ULF) waves in the plasmaspheric boundary layer on 10 September 2015. Strongly enhanced cold electron fluxes in the energy spectrogram were observed along with second harmonic mode waves with a period of about 1 minute which lasted several hours during two consecutive Van Allen Probe B orbits. Cold electron (<200 eV) and energetic proton (10-20 keV) bi-directional pitch angle signatures observed during the event are suggestive of the drift-bounce resonance mechanism. The correlation between enhanced energy fluxes and ULF waves leads to the conclusions that plasmaspheric dynamics is strongly affected by ULF waves. Van Allen Probe A and B, GOES 13, GOES 15 and MMS 1 observations suggest ULF waves in the event were strongest on the dusk-side magnetosphere. Measurements from MMS 1 contain no evidence of an external wave source during the period when ULF waves and injected energetic protons with a bump-on-tail distribution were detected by Van Allen Probe B. This suggests that the observed ULF waves were probably excited by a localized drift-bounce resonant instability, with the free energy supplied by substorm-injected energetic protons. The observations by Van Allen Probe B suggest that energy transfer between particle species in different energy ranges can take place through the action of ULF waves, demonstrating the important role of these waves in the dynamical processes of the inner magnetosphere.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- National Aeronautics and Space Administration (NASA); USDOE; National Natural Science Foundation of China (NSFC)
- Grant/Contract Number:
- AC52-06NA25396; 2012CB825603; 41627805
- OSTI ID:
- 1394991
- Report Number(s):
- LA-UR-17-27492
- Journal Information:
- Journal of Geophysical Research. Space Physics, Vol. 122, Issue 10; ISSN 2169-9380
- Publisher:
- American Geophysical UnionCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Field‐Aligned Structures of the Poloidal‐Mode ULF Wave Electric Field: Phase Relationship Implications
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journal | May 2019 |
Cold Plasmaspheric Electrons Affected by ULF Waves in the Inner Magnetosphere: A Van Allen Probes Statistical Study
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journal | October 2019 |
Eastward Propagating Second Harmonic Poloidal Waves Triggered by Temporary Outward Gradient of Proton Phase Space Density: Van Allen Probe A Observation
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journal | December 2019 |
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