scholarly journals Dynamics of modulationally unstable ion-acoustic wavepackets in plasmas with negative ions

2008 ◽  
Vol 74 (5) ◽  
pp. 639-656 ◽  
Author(s):  
MICHAEL S. RUDERMAN ◽  
TATYANA TALIPOVA ◽  
EFIM PELINOVSKY
Keyword(s):  
Nonlinear Theory ◽  
Acoustic Waves ◽  
Modulational Instability ◽  
Negative Ions ◽  
Ion Concentration ◽  
Negative Ion ◽  
Gardner Equation ◽  
Weakly Nonlinear ◽  
Weakly Nonlinear Theory ◽  
Ion Acoustic

AbstractIn this paper we study the propagation of nonlinear ion-acoustic waves in plasmas with negative ions. The Gardner equation governing these waves in plasmas with the negative ion concentration close to critical is derived. The weakly nonlinear theory of modulational instability based on the use of the nonlinear Schrödinger equation is discussed. The investigation of the nonlinear dynamics of modulationally unstable quasi-harmonic wavepackets is carried out by the numerical solution of the Gardner equation. The results are compared with the predictions of the weakly nonlinear theory.

Linear and nonlinear obliquely propagating ion-acoustic waves in magnetized negative ion plasma with non-thermal electrons

2013 ◽  
Vol 79 (5) ◽  
pp. 893-908 ◽  
Author(s):  
M. K. MISHRA ◽  
S. K. JAIN
Keyword(s):  
Acoustic Waves ◽  
Kdv Equation ◽  
Negative Ions ◽  
Ion Concentration ◽  
Negative Ion ◽  
Slow Mode ◽  
Ion Temperature ◽  
Ion Acoustic ◽  
Ion Acoustic Solitons ◽  
Ion Species

AbstractIon-acoustic solitons in magnetized low-β plasma consisting of warm adiabatic positive and negative ions and non-thermal electrons have been studied. The reductive perturbation method is used to derive the Korteweg–de Vries (KdV) equation for the system, which admits an obliquely propagating soliton solution. It is found that due to the presence of finite ion temperature there exist two modes of propagation, namely fast and slow ion-acoustic modes. In the case of slow-mode if the ratio of temperature to mass of positive ion species is lower (higher) than the negative ion species, then there exist compressive (rarefactive) ion-acoustic solitons. It is also found that in the case of slow mode, on increasing the non-thermal parameter (γ) the amplitude of the compressive (rarefactive) soliton decreases (increases). In fast ion-acoustic mode the nature and characteristics of solitons depend on negative ion concentration. Numerical investigation in case of fast mode reveals that on increasing γ, the amplitude of compressive (rarefactive) soliton increases (decreases). The width of solitons increases with an increase in non-thermal parameters in both the modes for compressive as well as rarefactive solitons. There exists a value of critical negative ion concentration (αc), at which both compressive and rarefactive ion-acoustic solitons appear as described by modified KdV soliton. The value of αc decreases with increase in γ.

scholarly journals Effect of Negative Ions on the Instability of Ion-acoustic Waves in a Relativistic Plasma

1997 ◽  
Vol 50 (2) ◽  
pp. 319 ◽  
Author(s):  
K. K. Mondal ◽  
S. N. Paul ◽  
A. Roychowdhury
Keyword(s):  
Dispersion Relation ◽  
Acoustic Wave ◽  
Acoustic Waves ◽  
Negative Ions ◽  
Ion Concentration ◽  
Negative Ion ◽  
Relativistic Velocity ◽  
Ion Acoustic Waves ◽  
Ion Acoustic Wave ◽  
Ion Acoustic

The dispersion relation of an ion-acoustic wave propagating through a collisionless, unmagnetised plasma, having warm isothermal electrons and cold positive and negative ions has been derived. It is seen that the ion-acoustic wave will be unstable in the presence of streaming of ions. Instability of the wave is graphically analysed for the plasma having (H+, O¯) ions, (H+, O2¯) ions, (H+, SF5¯) ions, (He+, Cl¯) ions and (Ar+, O¯) ions with different negative ion concentration and relativistic velocity.

scholarly journals Anomalous width variation of rarefactive ion acoustic solitary waves in the context of auroral plasmas

2004 ◽  
Vol 11 (2) ◽  
pp. 219-228 ◽  
Author(s):  
S. S. Ghosh ◽  
G. S. Lakhina
Keyword(s):  
Solitary Waves ◽  
Nonlinear Theory ◽  
Acoustic Waves ◽  
Large Amplitude ◽  
Magnetized Plasma ◽  
Amplitude Variation ◽  
Fully Nonlinear ◽  
Weakly Nonlinear ◽  
Ion Acoustic Solitary Waves ◽  
Ion Acoustic

Abstract. The presence of dynamic, large amplitude solitary waves in the auroral regions of space is well known. Since their velocities are of the order of the ion acoustic speed, they may well be considered as being generated from the nonlinear evolution of ion acoustic waves. However, they do not show the expected width-amplitude correlation for K-dV solitons. Recent POLAR observations have actually revealed that the low altitude rarefactive ion acoustic solitary waves are associated with an increase in the width with increasing amplitude. This indicates that a weakly nonlinear theory is not appropriate to describe the solitary structures in the auroral regions. In the present work, a fully nonlinear analysis based on Sagdeev pseudopotential technique has been adopted for both parallel and oblique propagation of rarefactive solitary waves in a two electron temperature multi-ion plasma. The large amplitude solutions have consistently shown an increase in the width with increasing amplitude. The width-amplitude variation profile of obliquely propagating rarefactive solitary waves in a magnetized plasma have been compared with the recent POLAR observations. The width-amplitude variation pattern is found to fit well with the analytical results. It indicates that a fully nonlinear theory of ion acoustic solitary waves may well explain the observed anomalous width variations of large amplitude structures in the auroral region.

Ion-acoustic waves in a degenerate multicomponent magnetoplasma

2012 ◽  
Vol 79 (2) ◽  
pp. 163-168 ◽  
Author(s):  
U. M. ABDELSALAM ◽  
M. M. SELIM
Keyword(s):  
Solitary Waves ◽  
Acoustic Waves ◽  
Three Dimensional ◽  
Negative Ions ◽  
Expansion Method ◽  
Reductive Perturbation Method ◽  
Negative Ion ◽  
Zk Equation ◽  
Ion Acoustic ◽  
Astrophysical Objects

AbstractThe hydrodynamic equations of positive and negative ions, degenerate electrons, and the Poisson equation are used along with the reductive perturbation method to derive the three-dimensional Zakharov–Kuznetsov (ZK) equation. The G′/G-expansion method is used to obtain a new class of solutions for the ZK equation. At certain condition, these solutions can describe the solitary waves that propagate in our plasma. The effects of negative ion concentrations, the positive/negative ion cyclotron frequency, as well as positive-to-negative ion mass ratio on solitary pulses are examined. Finally, the present study might be helpful to understand the propagation of nonlinear ion-acoustic solitary waves in a dense plasma, such as in astrophysical objects.

The influence of ion streaming and weak relativistic effects on the modulational instability of ion-acoustic waves

1992 ◽  
Vol 48 (3) ◽  
pp. 477-486
Author(s):  
E. J. Parkes
Keyword(s):  
Acoustic Waves ◽  
Averaging Method ◽  
Modulational Instability ◽  
Relativistic Effects ◽  
Instability Criterion ◽  
Ion Acoustic Waves ◽  
Weakly Nonlinear ◽  
Nonlinear Dispersion Relation ◽  
Ion Acoustic ◽  
Unmagnetized Plasma

The influence of ion streaming and weak relativistic effects on the modulational instability of ion-acoustic waves in a collisionless unmagnetized plasma is investigated. An averaging method is used to derive a weakly nonlinear dispersion relation, from which the instability criterion is deduced. Conflicting results in the literature are resolved.

Nonlinear dynamics of ion acoustic waves in quantum pair-ion plasmas

2015 ◽  
Vol 81 (5) ◽  
Author(s):  
Biswajit Sahu ◽  
Barnali Pal ◽  
Swarup Poria ◽  
Rajkumar Roychoudhury
Keyword(s):  
Mach Number ◽  
Acoustic Waves ◽  
Density Ratio ◽  
Negative Ions ◽  
Negative Ion ◽  
Quantum Plasma ◽  
Ion Acoustic Waves ◽  
Ion Density ◽  
Quantum Parameter ◽  
Ion Acoustic

The nonlinear properties of the ion acoustic waves (IAWs) in a three-component quantum plasma comprising electrons, and positive and negative ions are investigated analytically and numerically by employing the quantum hydrodynamic (QHD) model. The Sagdeev pseudopotential technique is applied to obtain the small-amplitude soliton solution. The effects of the quantum parameter$H$, positive to negative ion density ratio${\it\beta}$and Mach number on the nonlinear structures are investigated. It is found that these factors can significantly modify the properties of the IAWs. The existence of quasi-periodic and chaotic oscillations in the system is established. Switching from quasi-periodic to chaotic is possible with the variation of Mach number or quantum parameter$H$.

Oblique collision of plane ion acoustic solitons in a multicomponent plasma with negative ions

1999 ◽  
Vol 61 (1) ◽  
pp. 151-159 ◽  
Author(s):  
H. BAILUNG ◽  
Y. NAKAMURA
Keyword(s):  
Negative Ions ◽  
Resonant Interaction ◽  
Ion Concentration ◽  
Negative Ion ◽  
Oblique Collision ◽  
Resonance Amplitude ◽  
Multicomponent Plasma ◽  
Ion Acoustic ◽  
Ion Acoustic Solitons ◽  
Experimental Findings

The resonant interaction of compressive and rarefactive ion acoustic solitons is studied experimentally in a multicomponent plasma containing additional negative-ion species. With increasing concentration of negative ions, the resonance amplitude increases for compressive ion acoustic solitons when the angle of collision is fixed. When the negative-ion concentration is larger than a critical value, the rarefactive ion acoustic solitons undergo resonant interaction for a lower resonance amplitude. Theoretical predictions of the Korteweg–de Vries equation agree with experimental findings.

Modulational instability of ion-acoustic waves in a plasma with negative ions

1993 ◽  
Vol 48 (6) ◽  
pp. 4642-4647 ◽  
Author(s):  
M. K. Mishra ◽  
R. S. Chhabra ◽  
S. R. Sharma
Keyword(s):  
Acoustic Waves ◽  
Modulational Instability ◽  
Negative Ions ◽  
Ion Acoustic Waves ◽  
Ion Acoustic
Sign in / Sign up

Export Citation Format

Share Document