Modulational instability of ion acoustic waves in the presence of density gradients

1979 ◽  
Vol 57 (5) ◽  
pp. 642-644 ◽  
Author(s):  
I. R. Durrani ◽  
G. Murtaza ◽  
H. U. Rahman
Keyword(s):  
Density Gradient ◽  
Acoustic Waves ◽  
Schrodinger Equation ◽  
Modulational Instability ◽  
Collisionless Plasma ◽  
Higher Order ◽  
Density Gradients ◽  
Ion Acoustic Waves ◽  
Ion Acoustic ◽  
Non Linear

Using the Krylov–Bogoliubov–Mitropolsky method of perturbation for weak non-linearities, we study the modulational instability of ion-acoustic waves in a collisionless plasma in the presence of a density gradient. We find that the density gradient of second or higher order of perturbation does not effect the dispersion and the non-linearity coefficients in the non-linear Schrödinger equation.

scholarly journals Modulation Instability of Ion-Acoustic Waves in Plasma with Nonthermal Electrons

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Basudev Ghosh ◽  
Sreyasi Banerjee
Keyword(s):  
Acoustic Waves ◽  
Modulational Instability ◽  
Perturbation Technique ◽  
Collisionless Plasma ◽  
Multiple Scale ◽  
Ion Temperature ◽  
Nls Equation ◽  
Ion Acoustic Waves ◽  
Nonthermal Electrons ◽  
Ion Acoustic

Modulational instability of ion-acoustic waves has been theoretically investigated in an unmagnetized collisionless plasma with nonthermal electrons, Boltzmann positrons, and warm positive ions. To describe the nonlinear evolution of the wave amplitude a nonlinear Schrödinger (NLS) equation has been derived by using multiple scale perturbation technique. The nonthermal parameter, positron concentration, and ion temperature are shown to play significant role in the modulational instability of ion-acoustic waves and the formation of envelope solitons.

Effect of ion temperature and inhomogeneity on modulational instability of ion acoustic waves

1996 ◽  
Vol 56 (2) ◽  
pp. 229-236
Author(s):  
Ijaz-Ur Rahman Durrani
Keyword(s):  
Schrödinger Equation ◽  
Acoustic Waves ◽  
Schrodinger Equation ◽  
Modulational Instability ◽  
Inhomogeneous Plasma ◽  
Nonlinear Schrodinger Equation ◽  
Ion Temperature ◽  
Ion Acoustic Waves ◽  
Ion Acoustic ◽  
Critical Wavenumber

The propagation of ion acoustic waves in an inhomogeneous plasma is studied in the presence of finite ion temperature. The standard nonlinear Schrödinger equation is obtained, and the regions of instability are plotted. It is claimed that these extraneous factors tend to lower the value of the critical wavenumber.

scholarly journals The Excitation of Ion-acoustic Waves by a Magnetic Pump in Cylindrical Geometry

1983 ◽  
Vol 36 (5) ◽  
pp. 675
Author(s):  
NF Cramer ◽  
IJ Donnelly
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Acoustic Waves ◽  
Pump Wave ◽  
Modulational Instability ◽  
Collisionless Plasma ◽  
Cylindrical Geometry ◽  
Alfvén Waves ◽  
Ion Acoustic Waves ◽  
Ion Acoustic

The modulational, parametric and purely 8rowing mode instabilities of a magnetic pump with a finite radial wavenumber in cylindrical geometry are investigated. The modulational instability is compared with the instability of a parallel propagating pump wave, and the growth rates are found to be similar. The growth rate of a pair of ion-acoustic waves is shown to be zero for a collisionless plasma, in agreement with less general results found previously. The growth rate in the collisional case is found to be nonzero. The purely growing mode growth rate is calculated for excitation of ionacoustic plus torsional Alfven waves.

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