scholarly journals Rapid Frequency Variations Within Intense Chorus Wave Packets

2020 ◽  
Vol 47 (15) ◽  
Author(s):  
X.‐J. Zhang ◽  
D. Mourenas ◽  
A. V. Artemyev ◽  
V. Angelopoulos ◽  
W. S. Kurth ◽  
...  
Keyword(s):  
Wave Packets ◽  
Frequency Variations ◽  
Chorus Wave

scholarly journals Field-aligned chorus wave spectral power in Earth's outer radiation belt

2015 ◽  
Vol 33 (5) ◽  
pp. 583-597 ◽  
Author(s):  
H. Breuillard ◽  
O. Agapitov ◽  
A. Artemyev ◽  
E. A. Kronberg ◽  
S. E. Haaland ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Radiation Belt ◽  
Spectral Power ◽  
Peak Frequency ◽  
Wave Power ◽  
Outer Radiation Belt ◽  
Substantial Impact ◽  
Wide Range ◽  
Frequency Variations ◽  
Chorus Wave

Abstract. Chorus-type whistler waves are one of the most intense electromagnetic waves generated naturally in the magnetosphere. These waves have a substantial impact on the radiation belt dynamics as they are thought to contribute to electron acceleration and losses into the ionosphere through resonant wave–particle interaction. Our study is devoted to the determination of chorus wave power distribution on frequency in a wide range of magnetic latitudes, from 0 to 40°. We use 10 years of magnetic and electric field wave power measured by STAFF-SA onboard Cluster spacecraft to model the initial (equatorial) chorus wave spectral power, as well as PEACE and RAPID measurements to model the properties of energetic electrons (~ 0.1–100 keV) in the outer radiation belt. The dependence of this distribution upon latitude obtained from Cluster STAFF-SA is then consistently reproduced along a certain L-shell range (4 ≤ L ≤ 6.5), employing WHAMP-based ray tracing simulations in hot plasma within a realistic inner magnetospheric model. We show here that, as latitude increases, the chorus peak frequency is globally shifted towards lower frequencies. Making use of our simulations, the peak frequency variations can be explained mostly in terms of wave damping and amplification, but also cross-L propagation. These results are in good agreement with previous studies of chorus wave spectral extent using data from different spacecraft (Cluster, POLAR and THEMIS). The chorus peak frequency variations are then employed to calculate the pitch angle and energy diffusion rates, resulting in more effective pitch angle electron scattering (electron lifetime is halved) but less effective acceleration. These peak frequency parameters can thus be used to improve the accuracy of diffusion coefficient calculations.

Fine Structure of Chorus Wave Packets: Comparison Between Observations and Wave Generation Models

2021 ◽  
Author(s):  
X.‐J. Zhang ◽  
A. G. Demekhov ◽  
Y. Katoh ◽  
D. Nunn ◽  
X. Tao ◽  
...  
Keyword(s):  
Fine Structure ◽  
Wave Packets ◽  
Wave Generation ◽  
Chorus Wave

Generation of realistic short chorus wave packets

2021 ◽  
Author(s):  
D. Nunn ◽  
X.‐J. Zhang ◽  
D. Mourenas ◽  
A. V. Artemyev
Keyword(s):  
Wave Packets ◽  
Chorus Wave

scholarly journals New results of investigations of whistler-mode chorus emissions

2008 ◽  
Vol 15 (4) ◽  
pp. 621-630 ◽  
Author(s):  
O. Santolík
Keyword(s):  
Nonlinear Theory ◽  
Wave Packets ◽  
Source Region ◽  
Whistler Mode ◽  
Earth’S Magnetosphere ◽  
Earth's Magnetosphere ◽  
Theoretical Results ◽  
Nonlinear Nature ◽  
Chorus Wave

Abstract. This review summarizes selected recent results obtained during investigation of whistler-mode chorus emissions in the Earth's magnetosphere. Special attention is paid to results published during the last five years, with a focus on the results of the CLUSTER project. The nonlinear nature of chorus emissions is demonstrated using both theoretical results and measurements. Selected areas of research on whistler-mode chorus are covered and the paper especially reports new results on substructure and amplitudes of chorus wave packets, on new observations of frequency differences of chorus wave packets at different points in space and on their possible interpretations, on results concerning determination of position and size of the source region of chorus, on recent observational and theoretical results which lead to improved description of propagation of chorus from its source, and, finally, on comparison of chorus measurements with corresponding values deduced from nonlinear theory and simulations.

Fine structure of large-amplitude chorus wave packets

2014 ◽  
Vol 41 (2) ◽  
pp. 293-299 ◽  
Author(s):  
O. Santolík ◽  
C. A. Kletzing ◽  
W. S. Kurth ◽  
G. B. Hospodarsky ◽  
S. R. Bounds
Keyword(s):  
Fine Structure ◽  
Large Amplitude ◽  
Wave Packets ◽  
Chorus Wave

scholarly journals Electron Nonlinear Resonant Interaction With Short and Intense Parallel Chorus Wave Packets

2018 ◽  
Vol 123 (6) ◽  
pp. 4979-4999 ◽  
Author(s):  
D. Mourenas ◽  
X.-J. Zhang ◽  
A. V. Artemyev ◽  
V. Angelopoulos ◽  
R. M. Thorne ◽  
...  
Keyword(s):  
Wave Packets ◽  
Resonant Interaction ◽  
Chorus Wave

scholarly journals Phase Decoherence Within Intense Chorus Wave Packets Constrains the Efficiency of Nonlinear Resonant Electron Acceleration

2020 ◽  
Vol 47 (20) ◽  
Author(s):  
X.‐J. Zhang ◽  
O. Agapitov ◽  
A. V. Artemyev ◽  
D. Mourenas ◽  
V. Angelopoulos ◽  
...  
Keyword(s):  
Wave Packets ◽  
Electron Acceleration ◽  
Resonant Electron ◽  
Phase Decoherence ◽  
Chorus Wave

scholarly journals Observations of the relationship between frequency sweep rates of chorus wave packets and plasma density

2010 ◽  
Vol 115 (A12) ◽  
pp. n/a-n/a ◽  
Author(s):  
E. Macúšová ◽  
O. Santolík ◽  
P. Décréau ◽  
A. G. Demekhov ◽  
D. Nunn ◽  
...  
Keyword(s):  
Plasma Density ◽  
Wave Packets ◽  
Frequency Sweep ◽  
The Relationship ◽  
Chorus Wave

Interferometric (Fourier-Spectroscopic) Measurement of Electron Energy Distributions

1990 ◽  
Vol 48 (2) ◽  
pp. 110-111 ◽  
Author(s):  
F. Hasselbach ◽  
A. Schäfer
Keyword(s):  
Group Velocity ◽  
Wave Packets ◽  
Index Of Refraction ◽  
Electron Wave ◽  
Fringe Contrast ◽  
Faraday Cage ◽  
Optical Index ◽  
Wien Filter ◽  
Coherent Wave ◽  
Electric And Magnetic Fields

Möllenstedt and Wohland proposed in 1980 two methods for measuring the coherence lengths of electron wave packets interferometrically by observing interference fringe contrast in dependence on the longitudinal shift of the wave packets. In both cases an electron beam is split by an electron optical biprism into two coherent wave packets, and subsequently both packets travel part of their way to the interference plane in regions of different electric potential, either in a Faraday cage (Fig. 1a) or in a Wien filter (crossed electric and magnetic fields, Fig. 1b). In the Faraday cage the phase and group velocity of the upper beam (Fig.1a) is retarded or accelerated according to the cage potential. In the Wien filter the group velocity of both beams varies with its excitation while the phase velocity remains unchanged. The phase of the electron wave is not affected at all in the compensated state of the Wien filter since the electron optical index of refraction in this state equals 1 inside and outside of the Wien filter.

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