Magnetosonic shocklets in electron-positron-ion plasmas

The formation and propagation characteristics of the magnetosonic shocks are investigated in a three-component magnetoplasma, consisting of warm dynamical ions with hot inertialess electrons and positrons. By solving the well-known nonlinear magnetohydrodynamic equations within the framework of diagonalization method, a set of two exact nonlinear wave equations is derived, which permits for both analytical as well as numerical solutions. It is shown that coherent solitary structures are formed at time τ = 0, which transform into the magnetosonic shocklets with the passage of time (τ > 0) because of the rapid steepening of ion-fluid velocity and magnetic field perturbations. The nonlinear ponderomotive force could be the major responsible force behind the wave steepening and wave breaking in such plasmas. Furthermore, the variation of plasma β, the positron-to-electron density ratio p and the ion-to-electron temperature ratio σ significantly modifies the profiles of the ion-fluid velocity and magnetic field. The present study might be useful for understanding the nonlinear propagation of magnetosonic shocklets in interstellar medium and in laboratory plasma experiments, where an additional positron-component exist. (paper)