Effects of ion-temperature on propagation of the large-amplitude ion-acoustic solitons in degenerate electron-positron-ion plasmas

2010 ◽  
Vol 17 (8) ◽  
pp. 082315 ◽  
Author(s):  
M. Akbari-Moghanjoughi
Keyword(s):  
Large Amplitude ◽  
Degenerate Electron ◽  
Ion Temperature ◽  
Electron Positron ◽  
Ion Acoustic ◽  
Ion Acoustic Solitons

scholarly journals Effects of Positron Density and Temperature on Large Amplitude Ion-acoustic Waves in an Electron - Positron - Ion Plasma

1997 ◽  
Vol 50 (2) ◽  
pp. 309 ◽  
Author(s):  
Y. N. Nejoh
Keyword(s):  
Acoustic Waves ◽  
Large Amplitude ◽  
Density Ratio ◽  
Present Theory ◽  
Electron Mass ◽  
Mass Ratio ◽  
Ion Acoustic Waves ◽  
Ion Plasma ◽  
Electron Positron ◽  
Ion Acoustic

The nonlinear wave structures of large amplitude ion-acoustic waves are studied in a plasma with positrons. We have presented the region of existence of the ion-acoustic waves by analysing the structure of the pseudopotential. The region of existence sensitively depends on the positron to electron density ratio, the ion to electron mass ratio and the positron to electron temperature ratio. It is shown that the maximum Mach number increases as the positron temperature increases and the region of existence of the ion-acoustic waves spreads as the positron temperature increases. The present theory is applicable to analyse large amplitude ion-acoustic waves associated with positrons which may occur in space plasmas.

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 Propagation of ion-acoustic solitary waves in a relativistic electron-positron-ion plasma

2011 ◽  
Vol 89 (3) ◽  
pp. 299-309 ◽  
Author(s):  
E. Saberian ◽  
A. Esfandyari-Kalejahi ◽  
M. Akbari-Moghanjoughi
Keyword(s):  
Solitary Wave ◽  
Relativistic Electron ◽  
Solitary Waves ◽  
Thermal Energy ◽  
Large Amplitude ◽  
Considerable Effect ◽  
Potential Well ◽  
Electron Positron ◽  
Ion Acoustic Solitary Waves ◽  
Ion Acoustic

The propagation of large amplitude ion-acoustic solitary waves (IASWs) in a fully relativistic plasma consisting of cold ions and ultra-relativistic hot electrons and positrons is investigated using the Sagdeev pseudopotential method in a relativistic hydrodynamics model. The effects of streaming speed of the plasma fluid, thermal energy, positron density, and positron temperature on large amplitude IASWs are studied by analysis of the pseudopotential structure. It is found that in regions in which the streaming speed of the plasma fluid is larger than that of the solitary wave, by increasing the streaming speed of the plasma fluid, the depth and width of the potential well increase, resulting in narrower solitons with larger amplitude. This behavior is opposite to the case where the streaming speed of the plasma fluid is less than that of the solitary wave. On the other hand, an increase in the thermal energy results in wider solitons with smaller amplitude, because the depth and width of the potential well decrease in that case. Additionally, the maximum soliton amplitude increases and the width becomes narrower as a result of an increase in positron density. It is shown that varying the positron temperature does not have a considerable effect on the width and amplitude of IASWs. The existence of stationary soliton-like arbitary amplitude waves is also predicted in fully relativistic electron-positron-ion (EPI) plasmas. The effects of streaming speed of the plasma fluid, thermal energy, positron density, and positron temperature on these kinds of solitons are the same for large amplitude IASWs.

Ion-acoustic solitons excited by a single grip

1975 ◽  
Vol 14 (2) ◽  
pp. 353-364 ◽  
Author(s):  
S. Watanabe
Keyword(s):  
Large Amplitude ◽  
Phase Delay ◽  
Step Voltage ◽  
Ion Acoustic ◽  
Ion Acoustic Solitons ◽  
Nonlinear Index ◽  
Mesh Grid ◽  
Positive Step

Ion-acoustic solitons are observed to form when a large-amplitude positive step voltage is applied to a single mesh grid. For the formation of the soliton, the sheath about the grid plays an important rôle. The number and the amplitude of the solitons are examined experimentally as a function of the nonlinear index, and are compared with theory. The observed width and the velocity of the soliton are well explained by the theory of a hot-ion fluid and Boltzmann electrons. The phase delay of two solitons by a head-on collision is also observed.

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