Formation of energetic electron butterfly distributions by magnetosonic waves via Landau resonance
- Peking Univ., Beijing (China). Inst. of Space Physics and Applied Technology; Univ. of California, Los Angeles, CA (United States). Dept. of Atmospheric and Oceanic Sciences
- Wuhan Univ. (China). School of Electronic Information. Dept. of Space Physics
- Univ. of California, Los Angeles, CA (United States). Dept. of Atmospheric and Oceanic Sciences
- Peking Univ., Beijing (China). Inst. of Space Physics and Applied Technology
- Univ. of Texas, Dallas, TX (United States). W. B. Hanson Center for Space Sciences. Dept. of Physics
- Univ. of Colorado, Boulder, CO (United States). Lab. for Atmospheric and Space Physics
- Univ. of Iowa, Iowa City, IA (United States). Dept. of Physics and Astronomy
- The Aerospace Corporation, El Segundo, CA (United States). Space Science Applications Lab.
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Space Science and Applications Group
- Univ. of New Hampshire, Durham, NH (United States). Inst. for the Study of Earth, Oceans, and Space
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Memorial Univ. of Newfoundland, St. John's, NL (Canada). Dept. of Mathematics and Statistics
Radiation belt electrons can exhibit different types of pitch angle distributions in response to various magnetospheric processes. Butterfly distributions, characterized by flux minima at pitch angles around 90°, are broadly observed in both the outer and inner belts and the slot region. Butterfly distributions close to the outer magnetospheric boundary have been attributed to drift shell splitting and losses to the magnetopause. However, their occurrence in the inner belt and the slot region has hitherto not been resolved. In this study, by analyzing the particle and wave data collected by the Van Allen Probes during a geomagnetic storm, we combine test particle calculations and Fokker-Planck simulations to reveal that scattering by equatorial magnetosonic waves is a significant cause for the formation of energetic electron butterfly distributions in the inner magnetosphere. Finally, another event shows that a large-amplitude magnetosonic wave in the outer belt can create electron butterfly distributions in just a few minutes.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Peking Univ., Beijing (China); Univ. of California, Los Angeles, CA (United States); Wuhan Univ. (China)
- Sponsoring Organization:
- USDOE; National Science Foundation (NSF); National Aeronautics and Space Administration (NASA); Johns Hopkins University; National Natural Science Foundation of China (NSFC); Nature Science and Engineering Research Council of Canada (NSERC)
- Grant/Contract Number:
- AC52-06NA25396
- OSTI ID:
- 1338751
- Report Number(s):
- LA-UR--16-20481
- Journal Information:
- Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 7 Vol. 43; ISSN 0094-8276
- Publisher:
- American Geophysical Union (AGU)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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