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1. Controlling Factors of Chorus Spectral Gaps

   https://doi.org/10.1029/2023JA031893  

   Li, Jinxing; Bortnik, Jacob; Li, Wen; An, Xin; Lyons, Larry R; Kurth, William S; Hospodarsky, George B; Hartley, David P; Reeves, Geoffrey D; Funsten, Herbert O; et al (October 2024, Journal of Geophysical Research: Space Physics)

   Abstract The present study compares a single‐band chorus wave against a banded chorus wave observed by Van Allen Probes at adjacent times, and demonstrates that the single‐band chorus wave is associated with an anisotropic electron population over a broad energy range, while the banded chorus wave is accompanied by an electron phase space density plateau and an electron anisotropy reduction around Landau resonant energies. We further compare banded chorus waves with different spectral gap widths, and show that a wider spectral gap is associated with electron isotropization extending to higher energies with respect to the equatorial Landau resonant energy. We suggest that early generated chorus waves isotropize electrons via Landau resonant acceleration, and the waves that propagate to higher latitudes isotropize electrons at higher energies. The isotropization extending to higher energies leads to a larger spectral gap of new chorus waves after electrons bounce back to the equator. 

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2. Generation of Realistic Short Chorus Wave Packets

   https://doi.org/10.1029/2020GL092178  

   Nunn, D.; Zhang, X.‐J.; Mourenas, D.; Artemyev, A. V. (April 2021, Geophysical Research Letters)

   null (Ed.)
3. Rapid Frequency Variations Within Intense Chorus Wave Packets

   https://doi.org/10.1029/2020GL088853  

   Zhang, X.‐J.; Mourenas, D.; Artemyev, A. V.; Angelopoulos, V.; Kurth, W. S.; Kletzing, C. A.; Hospodarsky, G. B. (August 2020, Geophysical Research Letters)

   null (Ed.)
4. Evolution of Chorus Subpackets in the Earth's Magnetosphere

   https://doi.org/10.1029/2023GL105938  

   Chen, Huayue; Wang, Xueyi; Chen, Lunjin; Omura, Yoshiharu; Tsurutani, Bruce T; Lin, Yu; Xia, Zhiyang (November 2023, Geophysical Research Letters)

   Abstract Chorus subpackets/subelements are the wave packets occurring at intervals of ∼10–100 msec and are suggested to play a crucial role in the formation of substructures within pulsating aurora. In this study, we investigate the evolution of subpackets from the upstream to downstream regions. Using Van Allen Probe A measurements, we have found that the frequency of the upstream subpackets increases smoothly, but that of the downstream subpackets remains almost unchanged. Through a simulation in the real‐size magnetosphere, we have reproduced the subpackets with characteristics similar to those in observations, and revealed that the frequency chirping is influenced by both resonant current of electrons and wave amplitude due to nonlinear physics. Although the resonant currents in the upstream and downstream regions are comparable, the wave amplitude increases significantly during evolution, resulting in lower sweep rate in the downstream region. Our findings provide a fresh insight into the evolution of chorus subpackets. 

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5. Propagation of Chorus Waves Generated in Minimum‐B Pockets

   https://doi.org/10.1029/2021GL096478  

   Kang, Ning; Bortnik, Jacob; An, Xin; Claudepierre, Seth G. (December 2021, Geophysical Research Letters)