Ion-acoustic waves in a degenerate multicomponent magnetoplasma

2012 ◽  
Vol 79 (2) ◽  
pp. 163-168 ◽  
Author(s):  
U. M. ABDELSALAM ◽  
M. M. SELIM

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.

2010 ◽  
Vol 76 (3-4) ◽  
pp. 409-418 ◽  
Author(s):  
A. A. MAMUN ◽  
K. S. ASHRAFI ◽  
M. G. M. ANOWAR

AbstractThe dust ion-acoustic solitary waves (SWs) in an unmagnetized dusty adiabatic electronegative plasma containing inertialess adiabatic electrons, inertial single charged adiabatic positive and negative ions, and stationary arbitrarily (positively and negatively) charged dust have been theoretically studied. The reductive perturbation method has been employed to derive the Korteweg-de Vries equation which admits an SW solution. The combined effects of the adiabaticity of plasma particles, inertia of positive or negative ions, and presence of positively or negatively charged dust, which are found to significantly modify the basic features of small but finite-amplitude dust-ion-acoustic SWs, are explicitly examined. The implications of our results in space and laboratory dusty electronegative plasmas are briefly discussed.


Author(s):  
Anne de Bouard

We study the stability of positive radially symmetric solitary waves for a three dimensional generalisation of the Korteweg de Vries equation, which describes nonlinear ion-acoustic waves in a magnetised plasma, and for a generalisation in dimension two of the Benjamin–Bona–Mahony equation.


2013 ◽  
Vol 79 (5) ◽  
pp. 893-908 ◽  
Author(s):  
M. K. MISHRA ◽  
S. K. JAIN

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.


2012 ◽  
Vol 79 (1) ◽  
pp. 65-68 ◽  
Author(s):  
M. S. ZOBAER ◽  
N. ROY ◽  
A. A. MAMUN

AbstractA theoretical investigation on the nonlinear propagation of ion-acoustic waves in a degenerate dense plasma has been made by employing the reductive perturbation method. The Burger's equation has been derived, and numerically analyzed. The basic features of electrostatic shock structures have been examined. It has been shown that the plasma system under consideration supports the propagation of electrostatic shock structures. The implications of our results (obtained from this investigation) in compact astrophysical objects have been briefly discussed.


2015 ◽  
Vol 30 (40) ◽  
pp. 1550216 ◽  
Author(s):  
O. Rahman

The nonlinear propagation of dust-ion-acoustic (DIA) solitary waves (SWs) in an unmagnetized four-component dusty plasma containing electrons and negative ions obeying vortex-like (trapped) velocity distribution, cold mobile positive ions and arbitrarily charged stationary dust has been theoretically investigated. The properties of small but finite amplitude DIASWs are studied by employing the reductive perturbation technique. It has been found that owing to the departure from the Maxwellian electron and Maxwellian negative ion distribution to a vortex-like one, the dynamics of such DIASWs is governed by a modified Korteweg–de Vries (mKdV) equation which admits SW solution under certain conditions. The basic properties (speed, amplitude, width, etc.) of such DIASWs are found to be significantly modified by the presence of trapped electron and trapped negative ions. The implications of our results to space and laboratory dusty electronegative plasmas (DENPs) are briefly discussed.


1997 ◽  
Vol 50 (2) ◽  
pp. 319 ◽  
Author(s):  
K. K. Mondal ◽  
S. N. Paul ◽  
A. Roychowdhury

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.


2015 ◽  
Vol 81 (5) ◽  
Author(s):  
Biswajit Sahu ◽  
Barnali Pal ◽  
Swarup Poria ◽  
Rajkumar Roychoudhury

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$H$.


1999 ◽  
Vol 61 (2) ◽  
pp. 177-189 ◽  
Author(s):  
W. M. MOSLEM

The nonlinear wave structures of small-amplitude ion acoustic waves in a warm plasma with adiabatic negative-ion, positron and electron constituents traversed by a warm electron beam (with different temperatures) in the vicinity of the critical negative-ion density are investigated using reductive perturbation method. The basic set of equations is reduced to an evolution equation that includes quadratic and cubic nonlinearities. The effective potential of this equation agrees exactly, for small wave amplitudes, with the Sagdeev potential obtained from the original fluid equations using a pseudopotential method. This implies that the evolution equation holds not only in the vicinity of the critical negative-ion density but also in the whole range of negative-ion density under the condition of small wave amplitude.


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