Symmetric Pair Plasmas with Impurities and Acoustic Wave in it

Symmetric pair plasmas, consisting of two species with opposite charge and equal masses is an exciting field where not only unexpected phenomena have been experimentally identified, but also where new theoretic problems have been defined. The presence of such physical systems like the early universe. neutron stars, active galactic nuclei, and pulsar magnetosphere makes the understanding of pair plasma dynamics relevant study for astrophysics [1], [2]. Although electron-positron pair plasmas ( plasmas) have since long been in laboratories do not allow life times sufficiently long for the excitation and development of coherent structures like acoustic waves and solitons (the annihilation time is short in comparison to the plasma period). This drawback is not present in the recently available long-lived pair plasmas composed by electron-positron [3] or by single charged fullerene molecules ( plasmas) [4], [5]. This poses a unique possibility to investigate the collective behavior of a symmetric pair-ion (mass opposite charged fullerene is almost equal) plasma experimentally under controlled conditions. Electron-hole plasmas ( plasmas) in pure semiconductors also are symmetric pair plasmas if effective masses of electrons and holes are equal. Symmetric pair plasmas are the subject of increasing interest among physicists. A motivation for the study of pair plasma dynamics lies in the insight they provide into the dynamics of more general plasmas, often composed of species with very different masses. One of the main difficulties in the numerical research of ordinary electron-ion plasmas is the large difference between the two involved time scales. It was observed in particle-in-cell simulation that a current-carrying Maxwellian plasma composed of two species with not too different masses is unstable for below the threshold predicted by the linear theory. An integration of the full kinetic equation of both species is therefore computationally very expensive and often masked by numerical limitations and simplifications (e.g., modeling one of the species by fluid dynamics) have instead been used to investigate the long-term behavior.

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In single and multiion plasmas the large differences between the electron and ion masses typically give rise to different scales, which can be used to disentangle in a natural way long and short wavelength phenomena, or high and low frequency modes. Such distinctions disappear when studying symmetric pair plasma, where the equal masses and opposite charges destroy the scales. Symmetric pair plasmas demonstrate drastically other collective behavior than ordinary asymmetric electron-ion plasmas ( e ). A recent theoretical considerations [6] presents a strict proof of impossibility of stationary electrostatic (acoustic) structures such double layers, charged sheaths near electrodes or stationary solitary electrostatic waves in symmetric unmagnitized pair plasmas. The proof is based on the analysis of solutions of momentum and continuity equations of species and Poisson equation with Sagdeev pseudopotential technique. Polytrophic state laws of species with equal coefficients and equal indexes are substituted into the momentum equations. It means that the temperature of species are equal also and thermodynamic equilibrium is assumed. But in [8 ] show how this situation may be changed. In that article main idea is to assume a thermodynamic unequilibrium of pair i plasmas -+ plasma when temperature of species are not equal (T ). It is proved that in these symmetric pair plasma, but with not equal temperature of species acoustic mode may exist.

High temperature laboratory and space plasmas are characterized by the fact that the typical collisional time scale is much longer than the plasma dynamics time scale. As a consequence, these plasmas can be considered in first approximation as collisionlles and the dynamics as Hamiltonian Vlasov-Poisson model since the diffusive scale length is many orders of magnitude smaller than any dynamical or kinetic scale length. In the present study we discuss the properties of collisionless Vlasov-Poisson model in fluid approximation in context of pair plasmas. In symmetric pair plasmas, where both species have the same temperature, acoustic mode are impossible, but in that plasmas exists nonlinear amplitude modulation of electrostatic mode [7 ]. These mode mixed higher harmonics with basic waves and can gives envelope solitons. It is not a pure acoustic modes according to above remarks. Next we consider acoustic waves in symmetric pair fullerene plasmas (

) with two population of electrons: cold and hot.

The possibility of symmetric pair fullerene plasmas ( ) production involve discussion about existing such plasma completely without of electrons. Therefore it seem interesting to consider fullerene pair plasma with some numbers of electrons with two population: cold and hot.The dynamics of the acoustic waves in a fullerene pair plasmas with two popul

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