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

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

On the response of large-amplitude internal waves to upstream disturbances

2012 ◽  
Vol 702 ◽  
pp. 59-88 ◽  
Author(s):  
Roberto Camassa ◽  
Claudio Viotti
Keyword(s):  
Internal Waves ◽  
Large Amplitude ◽  
Shear Flows ◽  
Wave Packets ◽  
Shear Instability ◽  
Wave Crest ◽  
Wave Flow ◽  
Absorption Mechanism ◽  
Wide Range ◽  
Perturbation Parameters

AbstractLarge-amplitude internal solitary waves generate shear flows that intensify from the wings of the waves to their maxima. Upstream perturbations of the hydrostatic equilibrium in the form of wave packets along the path of wave propagation are expected to trigger shear instability and ultimately generate Kelvin–Helmholtz roll-ups. In contrast, as shown here with accurate simulations of incompressible stratified Euler equations, large internal waves can act as suppressors of perturbations. The precise understanding of the mechanisms leading to different outcomes, including whether instability is excited, is the focus of this work. Under the action of shear flows, small-amplitude wave packets undergo stretching and filamentation, which lead to significant absorption of perturbation energy into the background shear. It is found that this typical behaviour is present in the self-induced shear by internal waves, regardless of whether the shear is stable or unstable, and can leave a quieter state in the wave’s wake for a wide range of perturbation parameters. In the unstable case, even once perturbations are selected to excite the instability, our results show that this absorption can act to reduce growth in the strong-shear region, effectively making roll-up development observable only downstream of the wave crest. Our approach is both analytical and numerical; a model valid for relatively thin pycnoclines and suitable for local spectral analysis is devised and used. Energy diagnostics on the simulations are implemented to validate the numerics and illustrate the energy exchanges between background wave flow and its shear. A link between the absorption mechanism and the clustering of local eigenvalues along the wave is proposed. This promotes an energetic coupling among neutral modes stronger than what may be expected to occur in slowly varying flows, and gives rise to multi-modal transient dynamics of the kind often referred to as non-normality effects. For those cases in which the wave-induced shear meets the conditions for local instability, it is found that the growth of disturbances is selective with respect to the sign of the mode excited upstream. Elements of this phenomenon are interpreted by asymptotic analysis for spatial growth in time-independent slowly varying media.

scholarly journals Observations of large amplitude parallel electric field wave packets at the plasma sheet boundary

1998 ◽  
Vol 25 (6) ◽  
pp. 857-860 ◽  
Author(s):  
C. Cattell ◽  
J. Wygant ◽  
J. Dombeck ◽  
F. S. Mozer ◽  
M. Temerin ◽  
...  
Keyword(s):  
Electric Field ◽  
Plasma Sheet ◽  
Large Amplitude ◽  
Wave Packets ◽  
Parallel Electric Field ◽  
Field Wave

Dynamics and interference of fine-structure wave packets created by strong ultrashort pulses

2002 ◽  
Vol 49 (1-2) ◽  
pp. 183-200 ◽  
Author(s):  
CÉLINE NICOLE ◽  
MOHAMED AZIZ BOUCHENE ◽  
BERTRAND GIRARD
Keyword(s):  
Fine Structure ◽  
Wave Packets ◽  
Ultrashort Pulses

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.

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