Laboratory Experiments on Whistler Wave Interactions with Energetic Electrons

2006 ◽  
Author(s):  
Reiner L. Stenzel ◽  
J. M. Urrutia
Keyword(s):  
Laboratory Experiments ◽  
Whistler Wave ◽  
Wave Interactions ◽  
Energetic Electrons

Nonlinear wave interactions and evolution of a ring-beam distribution of energetic electrons

1988 ◽  
Vol 31 (8) ◽  
pp. 2238 ◽  
Author(s):  
S. Kainer ◽  
J. D. Gaffey ◽  
C. P. Price ◽  
X. W. Hu ◽  
G. C. Zhou
Keyword(s):  
Nonlinear Wave ◽  
Wave Interactions ◽  
Energetic Electrons ◽  
Nonlinear Wave Interactions

The Effects of Cracks and Fluids on Post-Seismic Healing

2020 ◽  
Author(s):  
Alison Malcolm ◽  
Somayeh Khajehpour Tadavani ◽  
Kristin Poduska
Keyword(s):  
Nonlinear Response ◽  
Laboratory Experiments ◽  
Recovery Process ◽  
Seismic Events ◽  
Wave Interactions ◽  
Material Control ◽  
Turn On ◽  
Nonlinear Mechanism ◽  
Underlying Mechanisms ◽  
Changing Noise

<p>It is now well established that large seismic events change the surrounding velocities, and that these velocities slowly recover over time.  Precisely which mechanisms control the recovery process are less well understood.  We present the results of laboratory experiments to better characterise what properties of the underlying material control the recovery process.  We do this by mixing two waves, one which perturbs the velocity of the sample (as an earthquake does in field data) and one which senses the change in velocity (as in changing noise correlations).  This is an inherently nonlinear experiment as we mix two waves and measure the effects of this wave mixing.  Within our experiments, we vary the properties of the samples to understand which are most important in controlling the nonlinear response.  We focus on two mechanisms.  The first is fractures and how changes in fracture properties change the nonlinear response.  The second is fluids, in particular the effect of low saturations on the nonlinear response.  By changing the fluids and fractures we can turn on and off the nonlinear mechanism, helping us to move toward a better understanding of the underlying mechanisms of these wave-wave interactions.</p>

Laboratory experiments on counter-propagating collisions of solitary waves. Part 1. Wave interactions

2014 ◽  
Vol 749 ◽  
pp. 577-596 ◽  
Author(s):  
Yongshuai Chen ◽  
Harry Yeh
Keyword(s):  
Solitary Waves ◽  
Water Surface ◽  
Laboratory Experiments ◽  
Wave Amplitude ◽  
Relative Reduction ◽  
Wave Interactions ◽  
Oblique Collision ◽  
Laboratory Results ◽  
Surface Profiles ◽  
Good Agreement

AbstractCollisions of counter-propagating solitary waves are investigated experimentally. Precision measurements of water-surface profiles are made with the use of the laser induced fluorescence (LIF) technique. During the collision, the maximum wave amplitude exceeds that calculated by the superposition of the incident solitary waves, and agrees well with both the asymptotic prediction of Su & Mirie (J. Fluid Mech., vol. 98, 1980, pp. 509–525) and the numerical simulation of Craig et al. (Phys. Fluids, vol. 18, 2006, 057106). The collision causes attenuation in wave amplitude: the larger the wave, the greater the relative reduction in amplitude. The collision also leaves imprints on the interacting waves with phase shifts and small dispersive trailing waves. Maxworthy’s (J. Fluid Mech., vol. 76, 1976, pp. 177–185) experimental results show that the phase shift is independent of incident wave amplitude. On the contrary, our laboratory results exhibit the dependence of wave amplitude that is in support of Su & Mirie’s theory. Though the dispersive trailing waves are very small and transient, the measured amplitude and wavelength are in good agreement with Su & Mirie’s theory. Furthermore, we investigate the symmetric head-on collision of the highest waves possible in our laboratory. Our laboratory results show that the runup and rundown of the collision are not simple reversible processes. The rundown motion causes penetration of the water surface below the still-water level. This penetration causes the post-collision waveform to be asymmetric, with each departing wave tilting slightly backward with respect to the direction of its propagation; the penetration is also the origin of the secondary dispersive trailing wavetrain. The present work extends the studies of head-on collisions to oblique collisions. The theory of Su & Mirie, which was developed only for head-on collisions, predicts well in oblique collision cases, which suggests that the obliqueness of the collision may not be important for this ‘weak’ interaction process.

scholarly journals Modeling whistler wave generation regimes in magnetospheric cyclotron maser

2004 ◽  
Vol 22 (10) ◽  
pp. 3561-3570 ◽  
Author(s):  
D. L. Pasmanik ◽  
A. G. Demekhov ◽  
V. Y. Trakhtengerts ◽  
M. Parrot
Keyword(s):  
Source Parameters ◽  
Energetic Electron ◽  
Low Frequency ◽  
Wave Generation ◽  
Whistler Wave ◽  
Particle Precipitation ◽  
Loss Cone ◽  
Energetic Electrons ◽  
Cyclotron Maser ◽  
Different Characteristics

Abstract. Numerical analysis of the model for cyclotron instability in the Earth's magnetosphere is performed. This model, based on the self-consistent set of equations of quasi-linear plasma theory, describes different regimes of wave generation and related energetic particle precipitation. As the source of free energy the injection of energetic electrons with transverse anisotropic distribution function to the interaction region is considered. A parametric study of the model is performed. The main attention is paid to the analysis of generation regimes for different characteristics of energetic electron source, such as the shape of pitch angle distributions and its intensity. Two mechanisms of removal of energetic electrons from a generation region are considered, one is due to the particle precipitation through the loss cone and another one is related to the magnetic drift of energetic particles. It was confirmed that two main regimes occur in this system in the presence of a constant particle source, in the case of precipitation losses. At small source intensity relaxation oscillations were found, whose parameters are in good agreement with simplified analytical theory developed earlier. At a larger source intensity, transition to a periodic generation occurs. In the case of drift losses the regime of self-sustained periodic generation regime is realized for source intensity higher than some threshold. The dependencies of repetition period and dynamic spectrum shape on the source parameters were studied in detail. In addition to simple periodic regimes, those with more complex spectral forms were found. In particular, alteration of spikes with different spectral shape can take place. It was also shown that quasi-stationary generation at the low-frequency band can coexist with periodic modulation at higher frequencies. On the basis of the results obtained, the model for explanation of quasi-periodic whistler wave emissions is verified.

scholarly journals Low-order models of wave interactions in the transition to baroclinic chaos

1996 ◽  
Vol 3 (3) ◽  
pp. 150-165 ◽  
Author(s):  
W.-G. Früh
Keyword(s):  
Laboratory Experiments ◽  
Phase Locking ◽  
Zonal Flow ◽  
Wave Interactions ◽  
Discontinuous Bifurcation ◽  
Two Layer Model ◽  
Resonant Triads ◽  
Multi Mode ◽  
Recent Laboratory ◽  
Low Order

Abstract. A hierarchy of low-order models, based on the quasi-geostrophic two-layer model, is used to investigate complex multi-mode flows. The different models were used to study distinct types of nonlinear interactions, namely wave- wave interactions through resonant triads, and zonal flow-wave interactions. The coupling strength of individual triads is estimated using a phase locking probability density function. The flow of primary interest is a strongly modulated amplitude vacillation, whose modulation is coupled to intermittent bursts of weaker wave modes. This flow was found to emerge in a discontinuous bifurcation directly from a steady wave solution. Two mechanism were found to result in this flow, one involving resonant triads, and the other involving zonal flow-wave interactions together with a strong β-effect. The results will be compared with recent laboratory experiments of multi-mode baroclinic waves in a rotating annulus of fluid subjected to a horizontal temperature gradient.

scholarly journals Three-wave Interactions Involving One Whistler

1975 ◽  
Vol 28 (1) ◽  
pp. 101 ◽  
Author(s):  
DB Melrose
Keyword(s):  
Radio Emission ◽  
Solar Corona ◽  
Plasma Frequency ◽  
Resonance Condition ◽  
Langmuir Wave ◽  
Wave Interaction ◽  
Whistler Wave ◽  
The Other ◽  
Wave Interactions ◽  
The Waves

Three-wave interactions in which one of the waves is a whistler and the other two are higher frequency waves are examined. The suggestion by Chiu (1970) and Chin (1972) that radio emission near the fundamental plasma frequency might arise in the solar corona from the coalescence of a whistler wave with a Langmuir wave is shown to be unacceptable because the resonance condition for the three-wave interaction cannot be satisfied.

Laboratory experiments on internal wave interactions with a pycnocline

2012 ◽  
Vol 53 (6) ◽  
pp. 1663-1679 ◽  
Author(s):  
Scott Wunsch ◽  
Alan Brandt
Keyword(s):  
Internal Wave ◽  
Laboratory Experiments ◽  
Wave Interactions
Sign in / Sign up

Export Citation Format

Share Document