Nonlinear spatiotemporal evolution of whistler mode chorus waves in Earth's inner magnetosphere

Summers, Danny; Omura, Yoshiharu; Miyashita, Y.; Lee, Dong Hun

doi:10.1029/2012ja017842

Cited by 47 publications

(53 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…First results, presented by , Fu et al (2014b) and He et al (2015), have revealed a complex and variable multi-component thermal plasma content. Therefore, further development of ray-tracing models-possibly including also nonlinear effects of wave amplification, see (Albert et al 2013;Summers et al 2012)-can be considered as an important direction of research for the modeling of the inner magnetosphere.…”

Section: Discussionmentioning

confidence: 99%

Oblique Whistler-Mode Waves in the Earth’s Inner Magnetosphere: Energy Distribution, Origins, and Role in Radiation Belt Dynamics

et al. 2016

View full text Add to dashboard Cite

International audienceIn this paper we review recent spacecraft observations of oblique whistler-mode waves in the Earth’s inner magnetosphere as well as the various consequences of the presence of such waves for electron scattering and acceleration. In particular, we survey the statistics of occurrences and intensity of oblique chorus waves in the region of the outer radiation belt, comprised between the plasmapause and geostationary orbit, and discuss how their actual distribution may be explained by a combination of linear and non-linear generation, propagation, and damping processes. We further examine how such oblique wave populations can be included into both quasi-linear diffusion models and fully nonlinear models of wave-particle interaction. On this basis, we demonstrate that varying amounts of oblique waves can significantly change the rates of particle scattering, acceleration, and precipitation into the atmosphere during quiet times as well as in the course of a storm. Finally, we discuss possible generation mechanisms for such oblique waves in the radiation belts. We demonstrate that oblique whistler-mode chorus waves can be considered as an important ingredient of the radiation belt system and can play a key role in many aspects of wave-particle resonant interactions

show abstract

Section: Discussionmentioning

confidence: 99%

Oblique Whistler-Mode Waves in the Earth’s Inner Magnetosphere: Energy Distribution, Origins, and Role in Radiation Belt Dynamics

et al. 2016

View full text Add to dashboard Cite

show abstract

“…A coherent wave element appears from the band of whistler‐mode waves. When the wave amplitude exceeds a certain threshold level, nonlinear wave potentials emerge with a time scale different from the linear growth rate [e.g., Hikishima et al , ; Summers et al , ]. Nonlinear wave potentials or electron holes are crucial in understanding the generation process of coherent whistler‐mode chorus emissions occurring in the region close to the magnetic equator [ Omura et al, , ].…”

Section: Introductionmentioning

confidence: 99%

Effect of the background magnetic field inhomogeneity on generation processes of whistler‐mode chorus and broadband hiss‐like emissions

2013

Self Cite

View full text Add to dashboard Cite

[1] By a series of self-consistent electron hybrid code simulations, we study the effect of the background magnetic field inhomogeneity on the generation process of whistler-mode chorus emissions. Chorus with rising tones are generated through nonlinear wave-particle interactions occurring around the magnetic equator. The mirror force plays an important role in the nonlinear interactions, and the spatial inhomogeneity of the background magnetic field is a key parameter of the chorus generation process. We have conducted numerical experiments with different spatial inhomogeneities to understand properties of the chorus generation process. We assume the same initial condition of energetic electrons at the magnetic equator in all simulation runs. The simulation results reveal that the spectral characteristics of chorus significantly vary depending on the magnetic field inhomogeneity. Whistler-mode emissions are generated and propagate away from the equator in all simulation runs, but distinct chorus elements with rising tones are only reproduced in the cases of small inhomogeneities. In the simulation that had the smallest inhomogeneity, we find excitation of broadband hiss-like emission (BHE) whose amplitudes are comparable to discrete chorus elements found in other simulation runs. The BHE consists of many wave elements with rising tones nonlinearly triggered in the region close to the magnetic equator. We show that the small spatial inhomogeneity of the background magnetic field results in the small threshold amplitude for the nonlinear wave growth and allows the triggering process of rising tone elements to emerge easily in the equatorial region of the magnetosphere.Citation: Katoh, Y., and Y. Omura (2013), Effect of the background magnetic field inhomogeneity on generation processes of whistler-mode chorus and broadband hiss-like emissions,

show abstract

“…Various aspects of this nonlinear theory have been verified by sophisticated full-scale simulations of the generation and growth of whistler-mode chorus elements by Omura et al (2008Omura et al ( , 2009, Hikishima et al (2009) ;Hikishima et al (2010) and Katoh and Omura (2011). Summers et al (2012b) …”

Section: Introductionmentioning

confidence: 99%

Effects of cold electron number density variation on whistler-mode wave growth

2014

View full text Add to dashboard Cite

Abstract. We examine how the growth of magnetospheric whistler-mode waves depends on the cold (background) electron number density N 0 . The analysis is carried out by varying the cold-plasma parameter a = (electron gyrofrequency) 2 /(electron plasma frequency) 2 which is proportional to 1/N 0 . For given values of the thermal anisotropy A T and the ratio N h /N 0 , where N h is the hot (energetic) electron number density, we find that, as N 0 decreases, the maximum values of the linear and nonlinear growth rates decrease and the threshold wave amplitude for nonlinear growth increases. Generally, as N 0 decreases, the region of (N h /N 0 , A T )-parameter space in which nonlinear wave growth can occur becomes more limited; that is, as N 0 decreases, the parameter region permitting nonlinear wave growth shifts to the top right of (N h /N 0 , A T ) space characterized by larger N h /N 0 values and larger A T values. The results have implications for choosing input parameters for full-scale particle simulations and also in the analysis of whistler-mode chorus data.

show abstract

Nonlinear spatiotemporal evolution of whistler mode chorus waves in Earth's inner magnetosphere

Cited by 47 publications

References 47 publications

Oblique Whistler-Mode Waves in the Earth’s Inner Magnetosphere: Energy Distribution, Origins, and Role in Radiation Belt Dynamics

Oblique Whistler-Mode Waves in the Earth’s Inner Magnetosphere: Energy Distribution, Origins, and Role in Radiation Belt Dynamics

Effect of the background magnetic field inhomogeneity on generation processes of whistler‐mode chorus and broadband hiss‐like emissions

Effects of cold electron number density variation on whistler-mode wave growth

Contact Info

Product

Resources

About