scholarly journals Excitation of lower hybrid wave by an ion beam in magnetized plasma

2013 ◽  
Vol 31 (4) ◽  
pp. 747-752 ◽  
Author(s):  
Ved Prakash ◽  
Ruby Gupta ◽  
Suresh C. Sharma ◽  
Vijayshri
Keyword(s):  
Growth Rate ◽  
Ion Beam ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Magnetized Plasma ◽  
Unstable Wave ◽  
Lower Hybrid ◽  
Hybrid Wave ◽  
Lower Hybrid Wave ◽  
Beam Density

AbstractLower hybrid wave excitation in magnetized plasma by an ion beam via Cerenkov interaction is studied. The lower hybrid modes showed maximum growth rate of the instability when phase velocity of the lower hybrid mode along the magnetic field is comparable to the electron thermal velocity. We have derived the expression for the maximum growth rate and found that the growth rate of the instability increases with beam density. Moreover, the maximum growth rate of the instability scales as the one-third power of the beam density. The real part of the frequency of the unstable wave increases as almost the square root of the beam energy.

Ion-beam–plasma electromagnetic instabilities

2000 ◽  
Vol 64 (1) ◽  
pp. 75-87 ◽  
Author(s):  
K. GOMBEROFF ◽  
L. GOMBEROFF ◽  
H. F. ASTUDILLO
Keyword(s):  
Growth Rate ◽  
Dispersion Relation ◽  
Electromagnetic Waves ◽  
Ion Beam ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Beam Density ◽  
Left Hand ◽  
Beam Velocity ◽  
Right Hand

It is well known that ion-beam–plasma interactions can destabilize right- and left-hand polarized electromagnetic waves. Owing to the fact that these instabilities have mostly been studied numerically by solving the hot-plasma dispersion relation, their fluid nature has often gone unnoticed. Choosing the ion background to be the rest frame, it is shown that the right-hand polarized instabilities are the result of a merging of the magnetosonic/electron-cyclotron branch of the dispersion relation with the ion beam. For any given ion-beam density and sufficiently large beam velocity, there are always two right- and two left-hand polarized instabilities leading to forward-propagating electromagnetic waves. It is also shown that all right-hand polarized instabilities are resonant instabilities, satisfying ω−kU+Ωp ≈ 0 around their maximum growth rate (ω and k are the frequency and the wavenumber respectively, U is the beam velocity, and Ωp is the proton gyrofrequency). Likewise, when the two left-hand instabilities are simultaneously present, they are also resonant instabilities satisfying ω ≈ Ωp. The high-frequency right-hand resonant instability (ω [Gt ] Ωp) has a maximum growth rate that depends only on the ratio between the beam density and the total density. The range of the unstable spectrum decreases with increasing beam velocity, leading to highly monochromatic radiation.

scholarly journals Weakly nonlinear waves in magnetized plasma with a slightly non-Maxwellian electron distribution. Part 1. Stability of solitary waves

2007 ◽  
Vol 73 (2) ◽  
pp. 215-229 ◽  
Author(s):  
M.A. ALLEN ◽  
S. PHIBANCHON ◽  
G. ROWLANDS
Keyword(s):  
Growth Rate ◽  
Solitary Waves ◽  
Nonlinear Waves ◽  
Electron Distribution ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Magnetized Plasma ◽  
Weakly Nonlinear ◽  
Weakly Nonlinear Waves ◽  
Stability Of Solitary Waves

Abstract.Weakly nonlinear waves in strongly magnetized plasma with slightly non-isothermal electrons are governed by a modified Zakharov–Kuznetsov (ZK) equation, containing both quadratic and half-order nonlinear terms, which we refer to as the Schamel–Korteweg–de Vries–Zakharov–Kuznetsov (SKdVZK) equation. We present a method to obtain an approximation for the growth rate, γ, of sinusoidal perpendicular perturbations of wavenumber, k, to SKdVZK solitary waves over the entire range of instability. Unlike for (modified) ZK equations with one nonlinear term, in this method there is no analytical expression for kc, the cut-off wavenumber (at which the growth rate is zero) or its corresponding eigenfunction. We therefore obtain approximate expressions for these using an expansion parameter, a, related to the ratio of the nonlinear terms. The expressions are then used to find γ for k near kc as a function of a. The approximant derived from combining these analytical results with the ones for small k agrees very well with the values of γ obtained numerically. It is found that both kc and the maximum growth rate decrease as the electron distribution becomes progressively less peaked than the Maxwellian. We also present new algebraic and rarefactive solitary wave solutions to the equation.

Quasimode decay of a lower-hybrid wave in a two-electron-temperature plasma

1996 ◽  
Vol 56 (2) ◽  
pp. 237-249
Author(s):  
A. Sudarshan ◽  
S. K. Sharma
Keyword(s):  
Growth Rate ◽  
Electron Temperature ◽  
Decay Channel ◽  
Lower Hybrid ◽  
Hybrid Wave ◽  
Lower Hybrid Wave ◽  
Temperature Plasma ◽  
Parametric Decay ◽  
Cylindrical Plasma ◽  
Ion Cyclotron

We study the quasimode decay of a lower-hybrid wave and a damped ion cyclotron wave in a plasma having two kinds of electrons. This decay channel is also investigated for a cylindrical plasma. The behaviour of the threshold and growth rate with variations in Tn/Tc and non/noc are studied, and a comparison is made with previous results. Our results show that the growth rate and the threshold for the onset of parametric decay are influenced by the presence of the second electron species.

Effect of dust charge fluctuations on upper hybrid wave instabilities in magnetized dusty plasma

2014 ◽  
Vol 32 ◽  
pp. 1460350 ◽  
Author(s):  
Jyotsna Sharma ◽  
Ajay Gahlot ◽  
Suresh C. Sharma ◽  
V. K. Jain
Keyword(s):  
Growth Rate ◽  
Dusty Plasma ◽  
Unstable Wave ◽  
Lower Hybrid ◽  
Hybrid Wave ◽  
Charge Fluctuations ◽  
Electrostatic Wave ◽  
Dust Charge ◽  
Magnetized Dusty Plasma ◽  
Dust Charge Fluctuations

The decay instability of an upper hybrid electrostatic wave into an upper hybrid sideband wave and lower hybrid wave is studied in magnetized dusty plasma. A local theory of this process has been developed. The growth rate and mode frequencies of the unstable wave were evaluated based on existing dusty plasma parameters and it is found that the unstable mode frequency and growth rate increases with δ (ion-to-electron density ratio) in the presence and absence of dust charge fluctuations in addition to dust dynamics.

scholarly journals Brillouin-shifted third-harmonic backscattering of laser in a magnetized plasma

2015 ◽  
Vol 33 (1) ◽  
pp. 97-102 ◽  
Author(s):  
Alireza Paknezhad
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Static Magnetic Field ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Magnetized Plasma ◽  
Third Harmonic ◽  
Coupled Equations ◽  
Relativistic Mass ◽  
Weakly Coupled

AbstractThird-harmonic Brillouin backscattering (3HBBS) instability is investigated in the interaction of a picosecond extraordinary laser pulse with a homogeneous transversely magnetized underdense plasma. Nonlinear coupled equations that describe the instability are derived and solved for a weakly coupled regime to find the maximum growth rate. The nonlinearity arises through the combined effect of relativistic mass increase, static magnetic field, and ponderomotive acceleration of plasma electrons. The growth rate is found to decrease as the static magnetic field increases. It also increases by increasing both plasma density and laser intensity. It is also established that the growth rate of 3HBBS instability in a magnetized plasma is lower than that of fundamental Brillouin backscattering instability.

scholarly journals Modulational Instability of Ion Acoustic Waves in a Magnetized Plasma Consisting of Isothermally Distributed Hot and Cold Electrons

2019 ◽  
pp. 1-13
Author(s):  
Sandip Dalui ◽  
Anup Bandyopadhyay
Keyword(s):  
Growth Rate ◽  
Acoustic Waves ◽  
Modulational Instability ◽  
Maximum Growth ◽  
Boltzmann Distribution ◽  
Maximum Growth Rate ◽  
Magnetized Plasma ◽  
Ion Acoustic Waves ◽  
Plasma System ◽  
Cold Electrons

Using the standard Reductive Perturbation Method a nonlinear Schr¨odinger equation is derived to study the modulational instability of small amplitude ion acoustic waves in a collisionless magnetized plasma composed of adiabatic warm ions, Maxwell-Boltzmann distribution of hot electrons as well as Maxwell-Boltzmann distribution of cold electrons, and the plasma system immersed in an external uniform static magnetic field (B0 = B0ˆz) propagating along the z-axis.The instability condition and the maximum growth rate of instability have been investigated analytically as well as numerically. We have studied the effect of each parameter of the present plasma system on the maximum growth rate of instability. In particular, it is found that the maximum growth rate of instability decreases with the increasing value of the ion cyclotron frequency with some set of values of the parameters associated with the present plasma system. Again, we have seen that the instability region decreases with the increasing value of the ion cyclotron frequency.

Parametric decay of an upper-hybrid wave in a plasma cylinder

1997 ◽  
Vol 58 (2) ◽  
pp. 277-285
Author(s):  
S. C. SHARMA
Keyword(s):  
Growth Rate ◽  
Nonlinear Interaction ◽  
Perturbation Technique ◽  
Wave Functions ◽  
Lower Hybrid ◽  
Hybrid Wave ◽  
Lower Hybrid Wave ◽  
Plasma Cylinder ◽  
Coupled Mode ◽  
Parametric Decay

A large-amplitude upper-hybrid wave in a plasma cylinder is susceptible to parametric decay into a lower-hybrid wave and an upper-hybrid wave. The perpendicular and parallel motions of electrons play equally important roles in the nonlinear interaction. The coupled-mode equations are solved using a perturbation technique. The growth rate of the instability is less sensitive to the radial mode number of the sideband. However, for higher-order radial modes it falls off as the overlap of the interacting wave functions decreases.

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