Ion-acoustic compressive and rarefactive double layers in a warm multicomponent plasma with negative ions

Abstract

Propagation of ion-acoustic double layers has been studied in plasma consisting of warm positive- and negative-ion species with different masses, concentrations, and charge states along with electrons with two-electron temperature distributions. It is found that there exist two critical concentrations of negative ions, alpha(R) and alpha(Q). One of them (alpha(R)) generally decides the existence of the double layer, whereas the other one (alpha(Q)) decides the nature of the double layer. It is found that the system supports ion-acoustic double layers only when the negative-ion concentration (alpha) is greater than the critical concentration alpha(R). It is also found that below the critical concentration alpha(Q), compressive double layers exist and above it rarefactive double layers exist. For some values of cold-electron concentrations (mu) it is found that if the temperature of the negative-ion species is higher than the positive-ion species, then the system supports compressive double layers for all values of alpha lying in the range 0<alpha<alpha(Q). The dependence of the critical concentrations on the temperatures of the two-ion species and on the concentration of cold electrons has also been investigated.

Higher-Order Nonlinear Effects on Wave Structures in a Multispecies Plasma with Nonisothermal Electrons

“…These results are consistent with those of Mamun and Shukla [81]. The solitary type solution of (15) having sech 4 profile, contains a peak amplitude which is a function of several parameters as relative density of negative ions α, relative ion-temperatures σ 1 , σ 2 , soliton velocity ν, and temperature ratio of free to trapped electrons β (= T ef /T et ), i. e. the trapped electron parameter. As already mentioned (14) is quadratic in λ 2 and correspondingly we have two modes, viz.…”

“…The effect of the nonisothermal parameter β , mass ratio η, and ion temperatures have been thoroughly studied. Associated profiles of sech 4 types are significantly modified by the inclusion of higher-order dispersive and nonlinear effects. The deviation of the isothermal behaviour is studied by deriving the generalized mKdV equation by Tagare and Chakrabarti [82].…”

“…slow ion-acoustic solitons and fast ion-acoustic solitons. Earlier investigations [3,4] reported two cases in which the system does not support the slow ion-acoustic mode, viz. :…”

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

“…9 Both compressive and rarefactive solitons, as well as double layers ͑depending on the concentration of low-temperature electrons͒, can be generated. Mishra et al 10 studied ion-acoustic double layers in a plasma consisting of warm positive-and negative-ion species and two-electron temperature distributions. It was found that both compressive as well as rarefactive double layers exist depending upon negative ion concentration being below or above the critical concentration, respectively.…”

Small amplitude electron-acoustic double layers and solitons in fully relativistic plasmas of two-temperature electrons

“…4,5 Double layers and solitary waves have been the subjects of many studies in the fields of space 6,7 and experimental plasma physics 8,9 in relation to the mechanism of particle acceleration and the interaction of nonlinear waves and plasmas. Many of theoretical studies on these nonlinear waves are based on KdV, mKdV, and mmKdV equations 10,11 because of the mathematically simple nonlinearity represented in terms of powers of perturbations. There have been numerous studies on the evolution of nonlinear waves by means of KdV, mKdV, and mmKdV equations in plasmas of nonrelativistic 10,12 and relativistic regimes.…”