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.

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.

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$H$.

Reflection of ion-acoustic waves from bipolar potential structures

1989 ◽  
Vol 41 (2) ◽  
pp. 243-255 ◽  
Author(s):  
Y. Nakamura ◽  
Joyanti Chutia
Keyword(s):  
Acoustic Wave ◽  
Acoustic Waves ◽  
High Efficiency ◽  
Ion Beam ◽  
Plasma Potential ◽  
Ion Acoustic Waves ◽  
Ion Acoustic Wave ◽  
Plasma Device ◽  
Ion Acoustic ◽  
Double Plasma Device

Reflection of ion-acoustic waves from the ion sheath in front of the separation grid in a double-plasma device has been investigated experimentally. The plasma potential φ of the source plasma was controlled relative to that of the target plasma. When eφ < κΤe, where Τe is the electron temperature, no reflection was observed. The reason for this is that ions are drifting towards the grid with the Bohm velocity, i.e. the ion-acoustic velocity. When eφ > κΤe the reflected wave consists of the ion-acoustic wave and the ion beam mode. The reflection coefficient for the ion-acoustic wave is about unity. This high efficiency is due to reflection of the ions themselves.

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.

Radio-auroral scattering at two closely spaced frequencies

1980 ◽  
Vol 58 (10) ◽  
pp. 1485-1491 ◽  
Author(s):  
I. P. W. Sinclair ◽  
P. A. Forsyth
Keyword(s):  
Acoustic Wave ◽  
Acoustic Waves ◽  
Ion Acoustic Waves ◽  
Ion Acoustic Wave ◽  
Individual Ion ◽  
Ion Acoustic ◽  
Wave Trains ◽  
Radio Frequencies

Two radio frequencies near 40 MHz and separated by 500 Hz were used to investigate the type of radio-auroral scattering which arises in ion-acoustic waves. The results confirm those of Haldoupis and Sofko who found that individual ion-acoustic wave trains have lifetimes of only tenths of seconds. In addition it was found that instantaneous signal amplitudes on these two frequencies were sometimes poorly correlated indicating the coexistence of widely separated ion-acoustic wave trains. It appears that the radio-auroral scattering region is typically large but within it individual ion-acoustic wave trains grow and decay rapidly. Significant periodicities were found in the signals and these are attributed to magnetospheric modulation of the auroral process.

Ion-acoustic waves and radio aurora

1970 ◽  
Vol 48 (16) ◽  
pp. 1863-1873 ◽  
Author(s):  
D. R. McDiarmid
Keyword(s):  
Acoustic Wave ◽  
Electric Field ◽  
Acoustic Waves ◽  
Polarization Field ◽  
Wave Instability ◽  
Ion Acoustic Waves ◽  
Ion Acoustic Wave ◽  
Proposed Model ◽  
Ion Acoustic

A previously proposed model of radio aurora is developed further and is used to relate and explain data obtained during an event described by Hofstee and Forsyth. The basis of the model is the two-stream, ion-acoustic wave instability. Although the model explains this particular event very well, attempts to apply it to certain other experimental situations have resulted in unresolved difficulties. These are discussed briefly.During the Hofstee and Forsyth event a geomagnetic bay was observed north of the scattering region. An explanation of this bay using the electric field deduced from the radio backscatter data required the assumption of a polarization field within the band of enhanced plasma associated with the visual aurora present at the same location (Boström's model 1).

scholarly journals Ion-Acoustic Instabilities in a Multi-Ion Plasma

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Noble P. Abraham ◽  
Sijo Sebastian ◽  
G. Sreekala ◽  
R. Jayapal ◽  
C. P. Anilkumar ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Acoustic Waves ◽  
Ion Acoustic Waves ◽  
Ion Acoustic Wave ◽  
Oxygen Ions ◽  
Ion Plasma ◽  
Thermal Spread ◽  
Ion Acoustic ◽  
Acoustic Instabilities ◽  
The Stability

We have, in this paper, studied the stability of the ion-acoustic wave in a plasma composed of hydrogen, positively and negatively charged oxygen ions, and electrons, which approximates very well the plasma environment around a comet. Modelling each cometary component (H+, O+, and O−) by a ring distribution, we find that ion-acoustic waves can be generated at frequencies comparable to the hydrogen ion plasma frequency. The dispersion relation has been solved both analytically and numerically. We find that the ratio of the ring speed (u⊥s) to the thermal spread (vts) modifies the dispersion characteristics of the ion-acoustic wave. The contrasting behaviour of the phase velocity of the ion-acoustic wave in the presence of O− ions for u⊥s>vts (and vice versa) can be used to detect the presence of negatively charged oxygen ions and also their thermalization.

scholarly journals Ion Acoustic Peregrine Soliton Under Enhanced Dissipation

2021 ◽  
Vol 8 ◽  
Author(s):  
Pallabi Pathak
Keyword(s):  
Acoustic Wave ◽  
Negative Ions ◽  
Landau Damping ◽  
Ion Acoustic Wave ◽  
Multicomponent Plasma ◽  
Plasma Device ◽  
Ion Acoustic ◽  
Damping Rate ◽  
Double Plasma Device ◽  
Spatial Damping

The effect of enhanced Landau damping on the evolution of ion acoustic Peregrine soliton in multicomponent plasma with negative ions has been investigated. The experiment is performed in a multidipole double plasma device. To enhance the ion Landau damping, the temperature of the ions is increased by applying a continuous sinusoidal signal of frequency close to the ion plasma frequency ∼1 MHz to the separation grid. The spatial damping rate of the ion acoustic wave is measured by interferometry. The damping rate of ion acoustic wave increases with the increase in voltage of the applied signal. At a higher damping rate, the Peregrine soliton ceases to show its characteristics leaving behind a continuous envelope.

Cylindrical ion-acoustic waves in a warm multicomponent plasma

2000 ◽  
Vol 63 (4) ◽  
pp. 343-353 ◽  
Author(s):  
S. K. EL-LABANY ◽  
S. A. EL-WARRAKI ◽  
W. M. MOSLEM
Keyword(s):  
Perturbation Theory ◽  
Acoustic Waves ◽  
Vries Equation ◽  
Negative Ions ◽  
Ion Acoustic Waves ◽  
Multicomponent Plasma ◽  
Reductive Perturbation ◽  
Ion Acoustic ◽  
Ion Acoustic Solitons ◽  
Warm Plasma

Cylindrical ion-acoustic solitons are investigated in a warm plasma with negative ions and multiple-temperature electrons through the derivation of a cylindrical Korteweg–de Vries equation using a reductive perturbation theory. The results are compared with those for the corresponding planar solitons.

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