Off-Equatorial Minima Effects on ULF Wave-Ion Interaction in the Dayside Outer Magnetosphere

Li, Xing-YuPeking Univ, Inst Space Phys & Appl Technol, Beijing, Peoples R China. (författare)

QC 20211025
The ultra-low frequency wave-particle drift-bounce resonance in the inner magnetosphere has been studied in detail, due to its important role in particle energization. However, it remains an open question how drift-bounce resonance manifests in the dayside outer magnetosphere, where particles' orbits show bifurcations because of off-equatorial magnetic field minima. In this study, we investigate this question, by analyzing Magnetospheric Multiscale observations of the January 20, 2017 event. A test-particle simulation is conducted to help us understand the observations. The observed pitch angle-time spectrograms show "pawtrack-like" structures. We find there are more than two resonant pitch angles at fixed energy, since off-equatorial minima change the relationship between the bounce (drift) frequency and pitch angle from unimodal function to trimodal function. These results reveal a new drift-bounce acceleration mechanism in the dayside outer magnetosphere, which potentially affects the efficiency of particle energization during geomagnetic activities like geomagnetic storms.

Liu, Zhi-YangPeking Univ, Inst Space Phys & Appl Technol, Beijing, Peoples R China. (författare)
Zong, Qiu-GangPeking Univ, Inst Space Phys & Appl Technol, Beijing, Peoples R China. (författare)
Zhou, Xu-ZhiPeking Univ, Inst Space Phys & Appl Technol, Beijing, Peoples R China. (författare)
Hao, Yi-XinPeking Univ, Inst Space Phys & Appl Technol, Beijing, Peoples R China. (författare)
Pollock, Craig J.Denali Sci, Fairbanks, AK USA. (författare)
Russell, Christopher T.Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90024 USA. (författare)
Lindqvist, Per-ArneKTH,Rymd- och plasmafysik(Swepub:kth)u1yukyk9 (författare)
Peking Univ, Inst Space Phys & Appl Technol, Beijing, Peoples R China.Denali Sci, Fairbanks, AK USA. (creator_code:org_t)

Ingår i:Geophysical Research Letters: American Geophysical Union (AGU)48:180094-82761944-8007

Av författaren/redakt...: Li, Xing-Yu; Liu, Zhi-Yang; Zong, Qiu-Gang; Zhou, Xu-Zhi; Hao, Yi-Xin; Pollock, Craig J ...; visa fler...; Russell, Christo ...; Lindqvist, Per-A ...; visa färre...

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