Observation of modulational instability in a multi-component plasma with negative ions

1993 ◽  
Vol 50 (2) ◽  
pp. 231-242 ◽  
Author(s):  
H. Bailung† ◽  
Y. Nakamura
Keyword(s):  
Schrödinger Equation ◽  
Nonlinear Schrödinger Equation ◽  
Acoustic Waves ◽  
Schrodinger Equation ◽  
Negative Ions ◽  
Nonlinear Schrodinger Equation ◽  
Ion Acoustic Waves ◽  
Nonlinear Schrödinger ◽  
Ion Acoustic ◽  
Component Plasma

The nonlinear evolution of ion-acoustic waves in a multi-component plasma with negative ions has been studied experimentally using a double-plasma device. At a critical concentration of negative ions the phase velocity of the ion- acoustic waves increases with the wave amplitude, and the wave has negative dispersion, which show that the wave satisfies Lighthill's condition. The initial small modulation in amplitude is found to grow spatially. The observed phenomena are compared with the relevant theory using the nonlinear Schrödinger equation. The fluid equations are integrated to confirm the validity of the nonlinear Schrödinger equation.

scholarly journals Stability of a modulated ion acoustic wave in a magnetised plasma.

2000 ◽  
Vol 53 (2) ◽  
pp. 289 ◽  
Author(s):  
Md. Khurshed Alam ◽  
A. Roy Chowdhury
Keyword(s):  
Schrödinger Equation ◽  
Acoustic Wave ◽  
Nonlinear Schrödinger Equation ◽  
Schrodinger Equation ◽  
Nonlinear Schrodinger Equation ◽  
Nls Equation ◽  
Ion Acoustic Wave ◽  
Nonlinear Schrödinger ◽  
Ion Acoustic ◽  
The Magnetic Field

A nonlinear Schrödinger equation which governs the nonlinear interaction of the ion-acoustic wave with the quasistatic plasma slow response in a magnetised plasma is deduced. The magnetic field is assumed to be constant. It is observed that the coefficient of the nonlinear term in the derived nonlinear Schrödinger equation turns out to be complex, in contrast to the usual situation. The condition for modulational stability is derived and it is found to be somewhat different. In the final section such a condition is discussed graphically. Our NLS equation goes back to that of the unmagnetised case if wc is put to zero.

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.

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