Equatorial Magnetosonic Waves: Do Nonlinear Interactions Play a Role in Their Evolution?

S N Walker,M A Balikhin,K H Yearby,H Aryan

doi:10.1029/2019ja027572

S N Walker, M A Balikhin + Show 2 more

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https://doi.org/10.1029/2019ja027572

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Abstract

AbstractThe occurrence of nonlinear interactions between discrete wave frequencies has been shown to play a significant role in the propagation and evolution of some plasma wave modes. In this paper we take advantage of closely spaced Cluster measurements to investigate the possibility nonlinear interactions occurring between the discrete emissions that are observed in a region of Equatorial Magnetosonic Wave generation. Based on transfer function analysis, it is shown that the role of nonlinear interactions plays a negligible role in the wave evolution as the emissions propagate from one satellite to the other. A bicoherence analysis of the individual signals also fails to find the existence of nonlinear interactions in the evolution of equatorial magnetosonic waves.

Highlights

IntroductionEquatorial magnetosonic waves (EMW) (or, equatorial noise; Gurnett, 1976; Russell et al, 1970) are commonly observed in the terrestrial inner magnetosphere (Boardsen et al, 2016; Laakso et al, 1990; Perraut et al, 1982; Posch et al, 2015)
Equatorial magnetosonic waves (EMW) are commonly observed in the terrestrial inner magnetosphere (Boardsen et al, 2016; Laakso et al, 1990; Perraut et al, 1982; Posch et al, 2015)
In this paper we take advantage of closely spaced Cluster measurements to investigate the possibility nonlinear interactions occurring between the discrete emissions that are observed in a region of Equatorial Magnetosonic Wave generation

Summary

Introduction

Equatorial magnetosonic waves (EMW) (or, equatorial noise; Gurnett, 1976; Russell et al, 1970) are commonly observed in the terrestrial inner magnetosphere (Boardsen et al, 2016; Laakso et al, 1990; Perraut et al, 1982; Posch et al, 2015) They usually appear as a regularly spaced series of discrete emissions at frequencies corresponding to harmonics of the proton gyrofrequency in the region in which they were generated in the frequency range with an upper limit in the vicinity of the lower hybrid frequency.

Data and Methodology

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