Streaming positron beams effect on the nonlinear structures in a relativistic multicomponent dusty plasma

In antimatter related research, the existence of electron-positron (e-p) in various astrophysical environments, Tokamak devices as well as in experimentally produced by explosions with highly intense laser beam experiments have already been confirmed. In plasmas, the presence of ions along with electron-positron (e-p) pair of astrophysical interest have given the researchers to study electron-positron-ion (e-p-i) plasmas in a larger domain. However, the massive charged dust particles are frequently find in astrophysical as well as in laboratory plasmas showing some peculiar behavior in the form of complex dusty plasmas. Moreover, when we consider a plasma influenced by the relativistic effect having streaming flow velocity of positron beam, one can expect to get instability in plasma due to the free energy source available to the system. This instability plays a major role in propagation, damping as well as in breaking of a solitary wave in plasmas. In this work, we proceed a theoretical study on four component relativistic plasma comprising mobile positively charged ions, mobile positron beam, negatively charged background dust and a nonthermal electron. By using reductive perturbation method, the K-dV equation is solved numerically. Here, we observed the influence of streaming positron beam on the propagation characteristics of solitary waves for different plasma constituents. It is found that the influence of relativistic effect on the streaming positron beam and positively charged ion does increase the phase velocity (Mach number) variation up-to the hypersonic regime, for the certain plasma parameters. Also, for the certain plasma conditions and for the plasma parameters used, we get a critical point where the formation of both positive (compressive) and negative (rarefactive) potential solitary waves are possible. The presence of increasing concentrations of both negatively charged background dust and nonthermal electron parameter achieve the increase in the potential of compressive solitary wave. While, with the increase in relativistic streaming factor of positron beam and the temperature ratios, the decrease in the potential of compressive IA solitary wave is observed. The findings may helpful in understanding the Earth upper atmospheres (Ionosphere region) as well as the space plasmas. (author)