Electron hybrid code simulation of whistler-mode chorus generation with real parameters in the Earth’s inner magnetosphere

Katoh, Yutai; Omura, Yoshiharu

doi:10.1186/s40623-016-0568-0

Cited by 46 publications

(45 citation statements)

References 29 publications

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“…We carry out simulations by using an electron hybrid code (e.g., Katoh & Omura, , ; Katoh et al, ), which treats background cold electrons as a fluid and solves the motion of energetic electrons by the particle‐in‐cell method (Dawson, ). This code has been used for the investigation of the generation mechanism of chorus (Katoh & Omura, , , , ; Omura et al, , ). We use a spatially one‐dimensional simulation system along a field line.…”

Section: Simulation Modelmentioning

confidence: 99%

“…The generation process of chorus has been reproduced by a self‐consistent particle code (e.g., Hikishima et al, ; Katoh & Omura, , , , ; Omura et al, , ), clarifying that chorus are generated through nonlinear wave‐particle interactions occurring in the equatorial region of the magnetosphere. Omura et al (, ) proposed the nonlinear wave growth theory for the generation mechanism of chorus with rising tones, and the theory can consistently explain both simulation results (Katoh & Omura, , ) and observed properties of chorus (Kurita et al, ; Yagitani et al, ).…”

Section: Introductionmentioning

confidence: 99%

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Dependence of Generation of Whistler Mode Chorus Emissions on the Temperature Anisotropy and Density of Energetic Electrons in the Earth's Inner Magnetosphere

et al. 2018

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We carry out a series of self‐consistent electron hybrid code simulations for the dependence of chorus generation process on the temperature anisotropy and density of energetic electrons in the Earth's inner magnetosphere. We use the same magnetic field gradient in the simulation system and different temperature anisotropy AT for the initial distribution of energetic electrons at the magnetic equator. We conduct 6 sets of simulations for different AT from 4 to 9, changing the initial number density Nh of energetic electrons at the equator in each set of simulations. By analyzing the spectra obtained in the simulation results, we identify chorus elements with rising tones in the results for higher Nh but no distinct chorus in smaller Nh. We compare the simulation results with estimations of the threshold and optimum amplitude proposed by the nonlinear wave growth theory. We find that the chorus generation processes reproduced in the simulation results are consistently explained by the theoretical estimates. We also compare the simulation results with linear growth rates for all simulation runs. We find clear disagreement between the spectral characteristics of reproduced chorus and the predictions by the linear theory. The present study clarifies that the spectra of chorus are essentially different from those predicted by the linear theory and are determined fully by nonlinear processes of wave‐particle interactions in the chorus generation region.

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Section: Simulation Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dependence of Generation of Whistler Mode Chorus Emissions on the Temperature Anisotropy and Density of Energetic Electrons in the Earth's Inner Magnetosphere

et al. 2018

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“…An important class of the whistler mode waves, chorus, is characterized by discrete elements in the time‐frequency spectrum. It is known to be generated by nonlinear wave‐electron interactions in the vicinity of the geomagnetic equator, as was shown by numerous theoretical studies (Gołkowski & Gibby, ; Omura et al, ; Trakhtengerts, ), simulations (Hikishima et al, ; Katoh & Omura, ), and satellite observations (LeDocq et al, ; Kurita et al, ; Santolík et al, ).…”

Section: Introductionmentioning

confidence: 96%

Effects of Ducting on Whistler Mode Chorus or Exohiss in the Outer Radiation Belt

Hanzelka

Santolı́k

2019

Geophysical Research Letters

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Previously published statistics based on Cluster spacecraft measurements surprisingly show that in the outer radiation belt, lower band whistler mode waves predominantly propagate unattenuated parallel to the magnetic field lines up to midlatitudes, where ray tracing simulations indicated highly attenuated waves with oblique wave vectors. We explain this behavior by considering a large fraction of ducted waves. We argue that these ducts can be weak and thin enough to be difficult to detect by spacecraft instrumentation while being strong enough to guide whistler mode waves in a cold plasma ray tracing simulation. After adding a tenuous hot electron population, we obtain a strong effect of Landau damping on unducted waves, while the ducted waves experience less damping or even growth. Consequently, the weighted average of amplitudes and wave normal angles of a mixture of ducted and unducted waves provides us with strong quasi‐parallel waves, consistent with the observations.

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“…Conversely, fallingtone emissions are generated through the formation of electron "hills" (Omura 2014). Katoh and Omura (2016) carried out a self-consistent simulation of the whistlermode chorus generation process and showed that simulated spectral fine structures were similar to the Cluster spacecraft observation. They also suggested that oblique propagation of waves with respect to the magnetic field is essential for forming the half gyrofrequency gap.…”

Section: Introductionmentioning

confidence: 93%

The Plasma Wave Experiment (PWE) on board the Arase (ERG) satellite

Kasahara

Kasaba

Kojima

et al. 2018

Earth Planets Space

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The Exploration of energization and Radiation in Geospace (ERG) project aims to study acceleration and loss mechanisms of relativistic electrons around the Earth. The Arase (ERG) satellite was launched on December 20, 2016, to explore in the heart of the Earth's radiation belt. In the present paper, we introduce the specifications of the Plasma Wave Experiment (PWE) on board the Arase satellite. In the inner magnetosphere, plasma waves, such as the whistlermode chorus, electromagnetic ion cyclotron wave, and magnetosonic wave, are expected to interact with particles over a wide energy range and contribute to high-energy particle loss and/or acceleration processes. Thermal plasma density is another key parameter because it controls the dispersion relation of plasma waves, which affects wave-particle interaction conditions and wave propagation characteristics. The DC electric field also plays an important role in controlling the global dynamics of the inner magnetosphere. The PWE, which consists of an orthogonal electric field sensor (WPT; wire probe antenna), a triaxial magnetic sensor (MSC; magnetic search coil), and receivers named electric field detector (EFD), waveform capture and onboard frequency analyzer (WFC/OFA), and high-frequency analyzer (HFA), was developed to measure the DC electric field and plasma waves in the inner magnetosphere. Using these sensors and receivers, the PWE covers a wide frequency range from DC to 10 MHz for electric fields and from a few Hz to 100 kHz for magnetic fields. We produce continuous ELF/VLF/HF range wave spectra and ELF range waveforms for 24 h each day. We also produce spectral matrices as continuous data for wave direction finding. In addition, we intermittently produce two types of waveform burst data, "chorus burst" and "EMIC burst. " We also input raw waveform data into the software-type wave-particle interaction analyzer (S-WPIA), which derives direct correlation between waves and particles. Finally, we introduce our PWE observation strategy and provide some initial results. which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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Electron hybrid code simulation of whistler-mode chorus generation with real parameters in the Earth’s inner magnetosphere

Cited by 46 publications

References 29 publications

Dependence of Generation of Whistler Mode Chorus Emissions on the Temperature Anisotropy and Density of Energetic Electrons in the Earth's Inner Magnetosphere

Dependence of Generation of Whistler Mode Chorus Emissions on the Temperature Anisotropy and Density of Energetic Electrons in the Earth's Inner Magnetosphere

Effects of Ducting on Whistler Mode Chorus or Exohiss in the Outer Radiation Belt

The Plasma Wave Experiment (PWE) on board the Arase (ERG) satellite

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