Large-amplitude ion-acoustic double layers in multispecies plasma

1990 ◽  
Vol 68 (6) ◽  
pp. 474-478 ◽  
Author(s):  
S. L. Jain ◽  
R. S. Tiwari ◽  
S. R. Sharma
Keyword(s):  
Large Amplitude ◽  
Reductive Perturbation Method ◽  
Negative Ion ◽  
Double Layers ◽  
Ion Acoustic ◽  
Unmagnetized Plasma ◽  
Ion Acoustic Double Layers ◽  
Ion Species ◽  
Ion Impurity ◽  
Positive Ion

We have investigated the effect of second-ion species on the characteristics of a large-amplitude ion-acoustic double layers (IADL) in a collisionless, unmagnetized plasma consisting of hot and cold Maxwellian populations of electrons and two cold-ion species with different masses, concentrations, and charge states. After deriving the criteria for the existence of large-amplitude IADL, we find that the presence of a positive-ion impurity does not modify considerably the characteristics of large-amplitude IADL. However, the presence of a negative-ion impurity changes significantly the characteristics of large-amplitude IADL. We have also presented an analytic discussion of small-amplitude IADL using a reductive perturbation method.

On the existence of ion-acoustic double layers in negative-ion plasmas

1991 ◽  
Vol 46 (2) ◽  
pp. 247-254 ◽  
Author(s):  
S. Baboolal ◽  
R. Bharuthram ◽  
M. A. Hellberg
Keyword(s):  
Negative Ion ◽  
Double Layers ◽  
Positive Ions ◽  
Potential Formulation ◽  
Ion Acoustic ◽  
Negative Ion Plasmas ◽  
Temperature Electron ◽  
Arbitrary Amplitude ◽  
Ion Acoustic Double Layers ◽  
Ion Species

It is well known that ion-acoustic double layers occur in plasmas containing two-temperature electron species and positive ions. In a recent study Verheest suggested that such structures can occur when there is only one electron species but both negative and positive ion species. There a stationary modified Korteweg de Vries equation was derived to support his deduction. This prediction, however, contradicts our own arbitrary-amplitude studies, which also cover the Verheest parameter regime. Here we resolve the discrepancy by examining both approaches in the pseudo-potential formulation in more relevant detail. The implications of this study extend beyond the realm of the present subject.

Arbitrary-amplitude rarefactive ion-acoustic double layers in warm multi-fluid plasmas

1988 ◽  
Vol 40 (1) ◽  
pp. 163-178 ◽  
Author(s):  
S. Baboolal ◽  
R. Bharuthram ◽  
M. A. Hellberg
Keyword(s):  
Large Amplitude ◽  
Small Amplitude ◽  
Layer Structure ◽  
Double Layers ◽  
Good Qualitative Agreement ◽  
Double Layer Structure ◽  
Ion Acoustic ◽  
Arbitrary Amplitude ◽  
Ion Acoustic Double Layers ◽  
Ion Species

Large- and small-amplitude rarefactive ion-acoustic double layers have recently been studied in a fluid plasma with double Maxwellian electrons and a single cold ion species. Here the stationary large-amplitude theory is generalized to include two warm ion species. A technique for numerically solving the full nonlinear problem is presented. With it, useful predictions of the effect of ion temperatures and of light-ion contamination on the double-layer structure are made. A generalization to an arbitrary number of similar fluid components is pointed out. The small-amplitude perturbation theory is also extended to such a plasma, and in its restricted regime good qualitative agreement is obtained with the results of the large-amplitude theory.

Cut-off conditions and existence domains for large-amplitude ion-acoustic solitons and double layers in fluid plasmas

1990 ◽  
Vol 44 (1) ◽  
pp. 1-23 ◽  
Author(s):  
S. Baboolal ◽  
R. Bharuthram ◽  
M. A. Hellberg
Keyword(s):  
Negative Ion ◽  
Double Layers ◽  
Sagdeev Potential ◽  
Ion Acoustic ◽  
Negative Ion Plasmas ◽  
Ion Acoustic Solitons ◽  
Arbitrary Amplitude ◽  
Ion Species ◽  
Positive Ion

It is shown how existence domains for arbitrary-amplitude ion-acoustic solitons and double layers are determined numerically by cut-off conditions on the corresponding Sagdeev potential. A two-electron-temperature model is considered, and in positive-ion plasmas the cut-off conditions are given in terms of the electron parameters, while for negative-ion plasmas such conditions are described in terms of parameters characterizing the role of the negative ion species.

Time evolution of ion-acoustic double layers in an unmagnetized plasma

2008 ◽  
Vol 15 (8) ◽  
pp. 082304 ◽  
Author(s):  
R. Bharuthram ◽  
E. Momoniat ◽  
F. Mahomed ◽  
S. V. Singh ◽  
M. K. Islam
Keyword(s):  
Time Evolution ◽  
Double Layers ◽  
Ion Acoustic ◽  
Unmagnetized Plasma ◽  
Ion Acoustic Double Layers
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