Amplitude Ion Acoustic Double Layers Research Articles

Arbitrary amplitude ion acoustic double layer in plasma with k-distributed electrons and negative ions

In this paper we have discussed the consequence of superthermal electrons and negative ion concentration on the arbitrary amplitude ion-acoustic double layers (IA-DLs) for plasma comprising the hot negative and positive ions with kappa distribution electrons. The energy equation is deduced for ion acoustic waves using Pseudo potential technique. We have investigated different parametric regimes for the existence of rarefactive and compressive ion acoustic DLs. The existence of double layers in term of minimum and maximum Mach number has calculated numerically. The effect of spectral index k on the amplitude of DLs and depth of Sagdeev potential has been discussed in detail. From numerical analysis, it is found that the compressive DLs exist at low values of α and rarefactive double layer exist at higher values of α. On the other hand, the effect of ionic temperature ratio (σ 1 and σ 2) plays significant role for the formation of double layer. Our analytical work also shows that the system supports coexistence of compressive and rarefactive DLs. It is also observed that the mass ratio affect the basic properties of DLs. We expect that the present results may be used to explain the ion-acoustic double layer in space plasma, where two ionic species and superthermal electrons are observed NO52.35g.

Effects of two-temperature nonextensive electrons on ion-acoustic double layers

The dynamic behavior of large amplitude ion-acoustic double layers in a plasma is investigated in the presence of two-temperature nonextensive electrons. The effects of physical parameters, such as the temperature and concentration of positive ions on the formation and structure of double layer are discussed. It is shown that the depth of the Sagdeev potential and the amplitude of both positive and negative ion-acoustic double layers sensitively depend on the temperature and the concentration of positive ions. The obtained results are also compared with the results of a similar Maxwellian plasma with warm ions and two (cold and hot) electron species.

Double layers and solitary structures in electron-positron-ion plasma with Kappa distributed trapped electrons

The effect of electron trapping in an electron-positron-ion plasma is modeled with κ-distributed electrons. The trapped electron number density is truncated to some finite order of the electrostatic potential Φ. Small amplitude solitary structures with Sagdeev potential approach and reductive perturbation method (through Schamel equation) are found to be modified under the impact of superthermality index κ and trapping efficiency β. A modified Schamel equation which gives rise to the small amplitude double layers (SIADLs) is obtained. The role of various plasma parameters in particular, the superthermality index, the positron concentration, and the electron trapping efficiency on the small amplitude ion acoustic double layers (SIADLs) has been investigated. It can be inferred from this investigation that these parameters play modifying character in the formation of nonlinear structures like solitary waves and SIADLs in e–p–i plasma.

Small amplitude double layers in a warm electronegative plasma with trapped kappa distributed electrons

We employ quasipotential analysis to derive the Sagdeev potential which accounts for the effect of electron trapping in a warm electronegative plasma with κ-distributed electrons. The trapped electron density is truncated to some finite order of the electrostatic potential Φ. This consequently leads to an extended KdV equation which gives rise to small amplitude double layers (SIADLs). The effects of various plasma parameters, e.g., superthermality index, the electron trapping efficiency, the mass ratio of negative to positive ion, the number density ratio of electron to positive ion, and temperature ratio of positive ion to electron on the small amplitude ion acoustic double layers (SIADLs), have been investigated. It has been found that these parameters have a significant modifying role in the SIADLs.

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

Small amplitude ion-acoustic double layers in an unmagnetized and collisionless plasma consisting of cold positive ions, q -nonextensive electrons, and a cold electron beam are investigated. Small amplitude double layer solution is obtained by expanding the Sagdeev potential truncated method. The effects of entropic index q , speed and density of cold electron beam on double layer structures are discussed.

Large amplitude ion-acoustic double layers in a plasma having variable-charge dust grain particles

The dust grain charging effect on large amplitude ion-acoustic double layers in a dusty plasma are investigated by the numerical calculation. The nonlinear structures of ion-acoustic double layers are examined, showing that the characteristics of the double layer sensitively depend on the dust charging effect, the influence of the ion temperature, the electrostatic potential, and the Mach number. The flow of the plasma current to the surface of dust particles increases the dust charge numbers. The effect of the ion temperature decreases the propagation speed of the ion-acoustic double layers and decreases the dust charge numbers. It is found that rarefactive double layers can propagate in this system. New findings of large amplitude ion-acoustic double layers with the dust charging effect and finite ion temperature in a dusty plasma are predicted.

Ion acoustic double layers in a magnetized plasma in the presence of impurity ions

We present here an analytic solution for small amplitude ion acoustic double layers in a magnetized plasma consisting of mobile impurity ions, hot background electrons and ions. Considering the fluid equations to describe the impurity ions and Boltzmann equation of state for both electrons and ions we derive a linear dispersion relation and investigate the existence of small amplitude double layer solution. We show that double layer solutions can be obtained for both positively and negatively charged impurity ions.

Small amplitude ion acoustic double layers in dusty plasmas

The existence of small amplitude ion acoustic double layers in a plasma consisting of cold ions, a hot population of electrons and negatively charged dust particles is investigated. The effect of trapped electrons on the formation of double layers is also investigated. It is shown that both compressive and rarefactive double layers can occur.

Ion-acoustic double layers and solitons in multispecies auroral beam-plasmas

A general analysis for small amplitude ion-acoustic double layers and solitons is developed, taking into account any number of ion beams and their charges, together with cold and hot electrons. For auroral plasma parameters, the analysis predicts the excitation of fast and slow hydrogen (as well as oxygen) beam-acoustic modes, which can be either rarefactive double layers or rarefactive or compressive solitons. Variations in the temperature and beam speed of the hydrogen (oxygen) beam can lead to the conversion of modes from originally rarefactive double layers to rarefactive solitons and finally to compressive solitons. Fast and slow hydrogen beam-acoustic modes are the first to be excited. The excitation of fast and slow oxygen modes is usually possible for larger values of beam speeds or beam temperatures. The typical width and speed of the nonlinear modes are in good agreement with the observations of double layers and solitons by the S3-3 and Viking satellites.

Ion acoustic double layers and solitons in auroral plasma

Small amplitude ion acoustic double layers and solitons were studied in an auroral plasma consisting of hot and cold electrons and two cold ion species (e.g. oxygen-hydrogen). For the auroral plasma parameters, the analysis predicts either rarefactive double layers or rarefactive solitons or compressive solitons existing in distinct parametric space (N H, T H T C ) , where N H is a relative density of hot electrons and T H, C represents the temperature of hot (cold) electron population. An increase in the oxygen number density reduces the parametric region of rarefactive double layers and at the same time pushes it towards the higher N H values. Both the width (half width) of the double layer (solitons) and their velocities as predicted by the theory, assuming relative oxygen density of 0.2–0.8, are in good agreement with the observed values from the S3-3 and the Viking satellite data.

Double layers in a field-aligned current driven plasma

The solutions of small amplitude ion acoustic double layers in current-carrying plasma in the presence of the magnetic field have been presented. The electron beam along the magnetic field has only been considered and the drift velocity assumed to be less than the electron thermal velocity. The velocity, the width and the potential of such DLs are calculated.

Theory of weak ion acoustic double layers

We present a theory of small amplitude ion acoustic double layers in a homogeneous unmagnetized plasma. Using fluid equations for ions and a general equation of state for electrons, we show that such double layers exist when the free and reflected electron distributions are different from maxwellians.