Small amplitude ion-acoustic double layers in a plasma with superthermal electrons and thermal positrons

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.

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Small amplitude ion-acoustic double layers with cold electron beam and q-nonextensive electrons

Physics Letters A ◽

10.1016/j.physleta.2014.01.015 ◽

2014 ◽

Vol 378 (10) ◽

pp. 795-799 ◽

Cited By ~ 6

Author(s):

S. Ali Shan ◽

H. Saleem

Keyword(s):

Electron Beam ◽

Small Amplitude ◽

Double Layers ◽

Cold Electron ◽

Nonextensive Electrons ◽

Ion Acoustic ◽

Ion Acoustic Double Layers

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Ion-acoustic double layers in electron–positron–ion plasmas with finite ion temperature

Journal of Plasma Physics ◽

10.1017/s0022377813000159 ◽

2013 ◽

Vol 79 (5) ◽

pp. 661-675 ◽

Cited By ~ 13

Author(s):

S. K. JAIN ◽

M. K. MISHRA

Keyword(s):

Double Layer ◽

Small Amplitude ◽

Double Layers ◽

Cold Electron ◽

Ion Temperature ◽

Temperature Ratio ◽

Plasma Parameters ◽

Electron Positron ◽

Ion Acoustic ◽

Ion Acoustic Double Layers

AbstractThe large-amplitude ion-acoustic double layers in a collisionless plasma consisting of isothermal positrons, warm adiabatic ions and two-temperature distribution of electrons are investigated. Using the pseudo-potential approach, an energy-integral equation for the system has been derived which encompasses complete nonlinearity for the plasma system. The existence region of the double layers is analyzed numerically. It is found that for a selected set of physical parameters, the rarefactive double layer exists in the electron–positron–ion plasma. It is found that the existence regime of the double layer is very sensitive to the plasma parameters, e.g. cold electron concentration (μ) and temperature ratio of two electron species (β). An increase in the finite ion temperature ratio increases the amplitude of the rarefactive double layer. To study small-amplitude double layers, we have expanded the Sagdeev potential. In the case of small amplitude, it is found that the amplitude of the double layer increases with increase in ion temperature ratio (σ) and cold electron concentration (μ). However increase in positron concentration (α) and temperature ratio of positrons to electrons (γ) decreases the amplitude of the double layer. The effect of various plasma parameters on the characteristics of the double layers is discussed in detail. The results of the investigation may be helpful to understanding basic plasma characteristics in space.

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