Magnetosonic shocklets in electron-positron-ion plasmas

Abstract

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.

The effect of κ-distributed trapped electrons on fully nonlinear electrostatic solitary waves in an electron–positron-relativistic ion plasma

“…Moreover, at the origin, the curve must have a maximum value, imposing d 2 U(φ) d 2 φ | φ=0 < 0, hence it has is an unstable fixed point at the origin. This condition provides the minimum Mach number M min for which the localized solitary pulse solution for equation (18) exists. Finally, we are focused in parameter values for which U(φ) < 0-as obvious from (18)-which is realised in the interval 0 < φ < φ max ; here, φ max say, indicates the first nonzero root of U, i.e.…”

“…It can be seen that the potential well gets deeper and wider as the Mach number M increases. The electrostatic solitary pulse profile is obtained numerically from equation (18) and depicted in figure 1(b). We thus observe that as the pulse gets faster, i.e.…”

“…The nonlinear small amplitude-modulated electrostatic solitary excitations in an unmagnetized, weakly relativistic, degenerate e-p-i plasma have been analyzed [17]. Employing the of diagonalization method to solve the magnetohydrodynamic governing equations, the existence and propagation properties of the large amplitude magnetosonic shocks in a magnetoplasma, containing warm inertial ions with hot non-inertial positrons and electrons have been examined [18]. They have observed the formation of the coherent solitary structures at the beginning, which transformed into the magnetosonic shocklets over time due to the strong steepening of ion-flow velocity and magnetic field excitations.…”