Relativistic generalization of whistler mode modulational instability

1981 ◽  
Vol 59 (10) ◽  
pp. 1376-1379
Author(s):  
R. Prasad ◽  
G. P. Gupta ◽  
R. N. Singh
Keyword(s):  
Growth Rate ◽  
Wave Equation ◽  
Frequency Spectrum ◽  
Modulational Instability ◽  
Relativistic Plasma ◽  
Relativistic Generalization ◽  
Whistler Mode ◽  
Nonlinear Schrödinger ◽  
Whistler Mode Waves ◽  
Relativistic Particles

The modulational instability of whistler mode waves interacting with relativistic plasma has been studied. The application of the Karpman and Krushkal criterion to the nonlinear Schrödinger wave equation gives the spectrum of modulationally unstable whistler mode waves. The effect of relativistic particles on the growth rate and frequency spectrum of modulationally unstable whistler mode waves has been discussed.

Electron whistler mode instability in an inhomogeneous thermal plasma in the presence of an inhomogeneous beam of suprathermal electrons

1983 ◽  
Vol 29 (3) ◽  
pp. 439-448 ◽  
Author(s):  
H.A. Shah ◽  
V.K. Jain
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Dispersion Relation ◽  
Thermal Plasma ◽  
Uniform Magnetic Field ◽  
Inhomogeneous Plasma ◽  
Mode Instability ◽  
Whistler Mode ◽  
Suprathermal Electrons ◽  
Whistler Mode Waves

The excitation of the whistler mode waves propagating obliquely to the constant and uniform magnetic field in a warm and inhomogeneous plasma in the presence of an inhomogeneous beam of suprathermal electrons is studied. The full dispersion relation including electromagnetic effects is derived. In the electrostatic limit the expression for the growth rate is given. It is found that the inhomogeneities in both beam and plasma number densities affect the growth rates of the instabilities.

scholarly journals Study of Oblique Propagating Whistler Mode Waves in Presence of Parallel DC Electric Field in Magnetosphere of Saturn

2017 ◽  
Vol 6 (2) ◽  
pp. 26 ◽  
Author(s):  
R. Kaur ◽  
R. S. Pandey
Keyword(s):  
Growth Rate ◽  
Distribution Function ◽  
Energy Density ◽  
Wave Number ◽  
Number Density ◽  
Temperature Anisotropy ◽  
Loss Cone ◽  
Whistler Mode ◽  
Whistler Mode Waves ◽  
Magnetosphere Of Saturn

In this paper whistler mode waves have been investigated in magnetosphere of Saturn. The derivation for perturbed distribution function, dispersion relation and growth rate have been determined by using the method of characteristic and kinetic approach. Analytical expressions for growth rate and real frequency of whistlers propagating oblique to magnetic field direction are attained. Calculations have been performed at 6 radial distances in plasma sheet region of Saturn’s magnetosphere as per data provided by Cassini. Work has been extended for bi-Maxwellian as well as Loss-cone distribution function. Parametric analysis show that temperature anisotropy, increase in number density, energy density and angle of propagation increases the growth rate of whistler waves along with significant shift in wave number. In case of Loss-cone distribution, increase in growth rate of whistlers is significantly more than for bi-Maxwellian distribution function. Generation of second harmonics can also be seen in the graphs plotted. It is concluded that parallel DC field stabilizes the wave and temperature anisotropy, angle of propagation, number density and energy density of electrons enhances the growth rate. Thus the results are of importance in analyzing observed VLF emissions over wide spectrum of frequency range in Saturnian magnetosphere. The analytical model developed can also be used to study various types of instabilities in planetary magnetospheres. 

Obliquely propagating whistler mode waves in cold plasmas permeated by dilute low-β anisotropic plasmas

1977 ◽  
Vol 18 (1) ◽  
pp. 1-14 ◽  
Author(s):  
K. Hashimoto ◽  
I. Kimura
Keyword(s):  
Growth Rate ◽  
Landau Damping ◽  
Elementary Functions ◽  
Whistler Mode ◽  
Oblique Propagation ◽  
Wide Range ◽  
Analytic Expressions ◽  
Cold Plasmas ◽  
Whistler Mode Waves ◽  
Wave Normal

We analyse the growth rate of obliquely propagating whistler mode waves in a cold plasma that also contains some hot electrons in a bi-Maxwellian distribution. Approximate analytic expressions for the growth rate are derived explicitly. They are represented by elementary functions only, consisting of a Landau damping term and a cyclotron instability term. They are found to be valid for a wide range of wave normal angles. Landau damping in the oblique propagation does not always become larger even if the wave normal angles increase. The necessary conditions for the minimal parallel growth are Ω > 0.5Ωe and T≥> 2T∥ in the bi-Maxwellian hot plasma. This method is applied to calculations of the net growth along the ray paths of obliquely propagating non-ducted whistler mode waves in a model magnetosphere.

scholarly journals Experimental Observation of Modulational Instability in Crossing Surface Gravity Wavetrains

Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 105 ◽  
Author(s):  
James N. Steer ◽  
Mark L. McAllister ◽  
Alistair G. L. Borthwick ◽  
Ton S. van den Bremer
Keyword(s):  
Wave Equation ◽  
Modulational Instability ◽  
Experimental Measurements ◽  
Extreme Waves ◽  
First Order ◽  
Nonlinear Schrödinger ◽  
Numerical Predictions ◽  
Wave Basin ◽  
Time Marching ◽  
Modulational Stability

The coupled nonlinear Schrödinger equation (CNLSE) is a wave envelope evolution equation applicable to two crossing, narrow-banded wave systems. Modulational instability (MI), a feature of the nonlinear Schrödinger wave equation, is characterized (to first order) by an exponential growth of sideband components and the formation of distinct wave pulses, often containing extreme waves. Linear stability analysis of the CNLSE shows the effect of crossing angle, θ , on MI, and reveals instabilities between 0 ∘ < θ < 35 ∘ , 46 ∘ < θ < 143 ∘ , and 145 ∘ < θ < 180 ∘ . Herein, the modulational stability of crossing wavetrains seeded with symmetrical sidebands is determined experimentally from tests in a circular wave basin. Experiments were carried out at 12 crossing angles between 0 ∘ ≤ θ ≤ 88 ∘ , and strong unidirectional sideband growth was observed. This growth reduced significantly at angles beyond θ ≈ 20 ∘ , reaching complete stability at θ = 30–40 ∘ . We find satisfactory agreement between numerical predictions (using a time-marching CNLSE solver) and experimental measurements for all crossing angles.

scholarly journals Radio waves and whistler-mode waves in solar wind and their interactions with energetic electrons

2020 ◽  
Author(s):  
Cynthia Cattell ◽  
Aaron Breneman ◽  
Lindsay Glesener ◽  
Ben Leiran ◽  
Ben Short ◽  
...  
Keyword(s):  
Solar Wind ◽  
Radio Waves ◽  
Whistler Mode ◽  
Energetic Electrons ◽  
Whistler Mode Waves
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