Nonlinear rarefactive isothermal ion acoustic waves in magnetized ultrarelativistic degenerate plasmas

Abstract

Nonlinear rarefactive isothermal ion-acoustic periodic travelling waves (RIIAPTWs) are examined in a magnetized ultrarelativistic degenerate plasma, containing warm fluid ions and ultrarelativistic degenerate inertialess electrons as well as positrons and immobile heavy negative ions. In the linear regime, the excitation of an isothermal ion-acoustic mode and its evolution are investigated. The physical behavior of nonlinear rarefactive isothermal ion-acoustic waves (RIIAWs) in this plasma model is governed by a Zakharov–Kuznetsov (ZK) equation. The analytical solutions for the nonlinear rarefactive isothermal ion-acoustic solitary waves (RIIASWs) and RIIAPTWs are performed by the bifurcation analysis. A careful discussion demonstrates the excitations of RIIASWs and RIIAPTWs are amplified (i.e., the amplitudes become deeper), as the chemical potential (or the Fermi energy at zero temperature) of electrons is decreased. It is found physically that the presence of the ultrarelativistic degenerate positrons and stationary heavy negative ions have strong effects on features of nonlinear RIIASWs and RIIAPTWs. The implications of the present finding in compact astrophysical objects, such as white dwarf stars, have been discussed.

Effects of trapped ions concentration on the dynamics of dust‐acoustic periodic travelling waves in dusty plasmas

“…Note that our numerical values of the amplitude of the electric field agree with the observations of electrostatic solitary waves in previous works, namely Pickett et al [ 21 ] and Moslem. [ 42 ]…”

“…Therefore, due to its important applications in various plasma environments, bifurcation theory has been extensively applied to examine the physical features of non‐linear waves in different plasma models. [ 37,42,51 ] As mentioned in the last part, we introduced the transformation, to obtain Equation (14). After integration and simplifying Equation (14), assuming , we obtain the following equation: …”

“…In addition, many investigators have applied bifurcation analysis [ 35 ] extensively to examine non‐linear waves' physical behaviour in different plasma models due to its significant applications in various plasma cases. [ 36–45 ] In particular, they discussed the probability of the existence and characteristics of periodic travelling waves. For instance, by applying the bifurcation theory, Abdelwahed et al [ 38 ] discussed the non‐linear propagation of dust‐ion acoustic periodic travelling waves in a dusty plasma consisting of cold ions, stationary charged dust grains, and two temperature superthermal electrons.…”

“…Abdelwahed et al found [ 38 ] that the superthermality of cold and hot electrons has a strong and weak influence, respectively, on the non‐linear dust‐ion acoustic periodic wave structures. Recently, El‐Shamy et al [ 42 ] examined non‐linear rarefactive isothermal ion‐acoustic periodic travelling waves in a magnetized ultrarelativistic degenerate plasma, including warm fluid ions, ultrarelativistic degenerate inertialess electrons as well as positrons, and immobile heavy negative ions. El‐Shamy et al [ 42 ] reported that the amplitudes of rarefactive isothermal ion‐acoustic periodic travelling waves become deeper as the chemical potential of electrons is decreased.…”

“…Recently, El‐Shamy et al [ 42 ] examined non‐linear rarefactive isothermal ion‐acoustic periodic travelling waves in a magnetized ultrarelativistic degenerate plasma, including warm fluid ions, ultrarelativistic degenerate inertialess electrons as well as positrons, and immobile heavy negative ions. El‐Shamy et al [ 42 ] reported that the amplitudes of rarefactive isothermal ion‐acoustic periodic travelling waves become deeper as the chemical potential of electrons is decreased. Very recently, Abdikian et al [ 45 ] have employed the bifurcation method to study non‐linear and supernonlinear ion‐acoustic waves in electron‐ion plasmas with generalized ( r , q )‐distributed electrons.…”