Nonlinear Electron Trapping Through Cyclotron Resonance in the Formation of Chorus Subpackets

Chen, Huayue; Wang, Xueyi; Chen, Lunjin; Zhang, Xiao‐Jia; Omura, Yoshiharu; Chen, Rui; Hsieh, Yi‐Kai; Lin, Yu; Xia, Zhiyang

doi:10.1029/2024gl109481

Cited by 3 publications

(2 citation statements)

References 47 publications

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“…Cyclotron resonant electrons are collected in the ranges of v ‖ /V Ae0 = 0.58-1.18, v ⊥ /V Ae0 = 2-4, and ζ = π-π/2, where ζ is the gyrophase angle between v ⊥ and wave perpendicular magnetic field δB ⊥ . Cyclotron resonant electrons trapped in wave phases are categorized into phase-trapped and phase-bunched electrons (Albert et al, 2021;Chen et al, 2024;Liu et al, 2012;Matsumoto & Omura, 1981;Nunn, 1974). In this study, a total of 7,651 cyclotron resonant electrons are collected, comprising 2,288 phase-trapped electrons and 5,363 phase-bunched electrons.…”

Section: Dynamics Of Cyclotron Resonant Electronsmentioning

confidence: 99%

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Electron Dynamics Associated With Advection and Diffusion in Self‐Consistent Wave‐Particle Interactions With Oblique Chorus Waves

Chen,

Wang,

Zhao

et al. 2024

Geophysical Research Letters

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Chorus waves are intense electromagnetic emissions critical in modulating electron dynamics. In this study, we perform two‐dimensional particle‐in‐cell simulations to investigate self‐consistent wave‐particle interactions with oblique chorus waves. We first analyze the electron dynamics sampled from cyclotron and Landau resonances with waves, and then quantify the advection and diffusion coefficients through statistical studies. It is found that phase‐trapped cyclotron resonant electrons satisfy the second‐order resonance condition and gain energy from waves. While phase‐bunched cyclotron resonant electrons cannot remain in resonance for long periods. They transfer energy to waves and are scattered to smaller pitch angles. Landau resonant electrons are primarily energized by waves. For both types of resonances, advection coefficients are greater than diffusion coefficients when the wave amplitude is large. Our study highlights the important role of advection in electron dynamics modulation resulting from nonlinear wave‐particle interactions.

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Section: Dynamics Of Cyclotron Resonant Electronsmentioning

confidence: 99%

“…Other details of the model are available in Wang et al (2024). The dynamics of resonant electrons are studied using the retracing method (Chen et al, 2024). They are collected at a specific time point T s and are analyzed from T 0 to T f , with T 0 < T s < T f .…”

Section: Simulation Modelmentioning

confidence: 99%

Electron Dynamics Associated With Advection and Diffusion in Self‐Consistent Wave‐Particle Interactions With Oblique Chorus Waves

Chen,

Wang,

Zhao

et al. 2024

Geophysical Research Letters

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Adiabatic theory of resonant particle dynamics with frequency chirping chorus waves in magnetospheric plasmas

Zheng,

Wang,

2024

Physics of Plasmas

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We present the adiabatic regime for the particles interacting with the frequency chirping waves in the inhomogeneous magnetic field. Despite the rapid change of the parameters during the interaction, we can construct an adiabatic invariant with new canonical coordinates, which is shown to be conserved as long as the particles stay trapped in the reference frame moving with the resonance. Assuming the trapped particle distribution as a function of the adiabatic invariant and the water-bag approximation, we derive an analytic form of the nonlinear current as a function of the inhomogeneous parameter that describes the frequency chirping and inhomogeneities in the background magnetic field. The nonlinear current expression is also examined in the Vlasov hybrid simulations, and the simulation results show that the nonlinear current can be well described by the adiabatic water-bag approximation, except for the chirping onset stage and the source region where the adiabatic approximation is invalid.

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Backward test particle simulation of nonlinear cyclotron wave-particle interactions in the radiation belts

Hosseini,

Harid,

Gołkowski

et al. 2024

Front. Astron. Space Sci.

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Wave-particle interaction plays a crucial role in the dynamics of the Earth’s radiation belts. Cyclotron resonance between coherent whistler mode electromagnetic waves and energetic electrons of the radiation belts is often called a coherent instability. Coherent instability leads to wave amplification/generation and particle acceleration/scattering. The effect of wave on particle’s distribution function is a key component of the instability. In general, whistler wave amplitude can grow over threshold of quasi-linear (linear) diffusion theory which analytically tracks the time-evolution of a particle distribution. Thus, a numerical approach is required to model the nonlinear wave induced perturbations on particle distribution function. A backward test particle model is used to determine the energetic electrons phase space dynamics as a result of coherent whistler wave instability. The results show the formation of a phase space features with much higher resolution than is available with forward scattering models. In the nonlinear regime the formation of electron phase space holes upstream of a monochromatic wave is observed. The results validate the nonlinear phase trapping mechanism that drives nonlinear whistler mode growth. The key differences in phase-space perturbations between the linear and nonlinear scenarios are also illustrated. For the linearized equations or for low (below threshold) wave amplitudes in the nonlinear case, there is no formation of a phase-space hole and both models show features that can be characterized as linear striations or ripples in phase-space.

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Nonlinear Electron Trapping Through Cyclotron Resonance in the Formation of Chorus Subpackets

Cited by 3 publications

References 47 publications

Electron Dynamics Associated With Advection and Diffusion in Self‐Consistent Wave‐Particle Interactions With Oblique Chorus Waves

Electron Dynamics Associated With Advection and Diffusion in Self‐Consistent Wave‐Particle Interactions With Oblique Chorus Waves

Adiabatic theory of resonant particle dynamics with frequency chirping chorus waves in magnetospheric plasmas

Backward test particle simulation of nonlinear cyclotron wave-particle interactions in the radiation belts

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