A Comparative Study of ULF Waves' Role in the Dynamics of Charged Particles in the Plasmasphere: Van Allen Probes Observation
- Peking Univ., Beijing (China). Inst. of Space Physics and Applied Technology; Nagoya Univ. (Japan). Solar-Terrestrial Environmental Lab.
- Peking Univ., Beijing (China). Inst. of Space Physics and Applied Technology
- Nagoya Univ. (Japan). Solar-Terrestrial Environmental Lab.
- Univ. of Alberta, Edmonton, AB (Canada). Dept. of Physics
- Univ. of New Hampshire, Durham, NH (United States). Dept. of Physics Inst. for Earth, Oceans and Space
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Univ. of Minnesota, Minneapolis, MN (United States). School of Physics and Astronomy
- Univ. of Iowa, Iowa City, IA (United States). Dept. of Physics and Astronomy
By analyzing observations from Van Allen Probes in its inbound and outbound orbits, we present evidence of coherent enhancement of cold plasmaspheric electrons and ions due to drift-bounce resonance with ultralow frequency (ULF) waves. From 18:00 UT on 28 May 2017 to 10:00 UT on 29 May 2017, newly formed poloidal mode standing ULF waves with significant electric field oscillations were observed in two consecutive orbits when Probe B was traveling inbound. In contrast to observations during outbound orbits, the cold (<150 eV) electrons measured by the HOPE instrument were characterized by flux enhancements several times larger and bidirectional pitch angle distributions during inbound orbits. The electron number density inferred from upper hybrid waves is twice as larger as during inbound orbits, which were also confirmed by an increase of spacecraft potential. The observed ULF waves are identified as second harmonic modes that satisfy the drift-bounce resonant condition of N = 1 with cold electrons. An enhancement of the plasmaspheric ion number density to restore charge neutrality of plasmas in inbound orbits is also observed, which is associated with an increase of ULF wave periods. The observations suggest that the dynamics of plasmaspheric electrons is modified by ULF waves through drift-bounce resonance and that plasmaspheric ions are indirectly impacted.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE; National Aeronautics and Space Administration (NASA); National Natural Science Foundation of China (NSFC); Natural Sciences and Engineering Research Council of Canada (NSERC); Canadian Space Agency
- Grant/Contract Number:
- AC52-06NA25396; 41421003; 41627805; NAS5‐01072
- OSTI ID:
- 1473821
- Report Number(s):
- LA-UR-18-26632
- Journal Information:
- Journal of Geophysical Research. Space Physics, Vol. 123, Issue 7; 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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