Solitary kinetic Alfvén waves in nonextensive electron-positron-ion plasma

Solitary kinetic Alfvén waves in dense plasmas with relativistic degenerate electrons and positrons

“…Further, if we increase the positron density, then the ion concentration in the system should be reduced in order to maintain the charge neutrality condition [33], and as KAWs are associated with the ion dynamics, therefore, both amplitude and width must decrease on increasing the positron density, which is evident from figure 2 (panel (c)). This result agrees to that reported in our previous paper [44] dealing with KAWs in nonextensive e-p-i plasma, which is relevant to long-range interacting interstellar and astrophysical plasma systems. It is also observed (figure 2 panel (d)) that an increase in the electron relativistic degeneracy parameter results into the reduction of both the width and the amplitude of solitary KAWs.…”

“…It is to be noted that the existence of sub-Alfvénic compressive solitary KAWs in our relativistic degenerate e-p-i plasma system is in agreement with those reported recently in degenerate e-p-i [35] as well as in e-i [41] plasmas but differs from reference [11] where supersonic, subsonic, and super-and sub-Alfvénic solitary waves were predicted in degenerate quantum e-i plasma under different relativistic regimes. This result is also similar to that reported in nondegenerate e-p-i plasmas [42][43][44], but is different from reference [45] where compressive solitons both at sub-and super-Alfvénic regime, were reported. In what follows, we analyze our results numerically in the context of dense astrophysical objects.…”

“…At the same time, the enhancement of relativistic degenerate velocities of electrons and positrons reduces the soliton width by decreasing the wave dispersion effect. However, in the case of nonextensive e-p-i plasma [44], it is reported that an increase in q-nonextensive parameter (which is associated with increase in the population of particles with lower velocities) reduces the amplitude and the width of solitary KAWs. To see the effect of relativistic degeneracy of lighter particles (i.e.…”

Nonlinear periodic coupled Alfvén and ion-acoustic wave structures in plasmas

“…They found that the coupled Alfvén and ion-acoustic waves soliton formed a hump structure, which propagates with sub-Alfvénic speed. Furthermore, Ahmed and Sah [15] studied the characteristics of coupled Alfvén and ion-acoustic waves in a nonextensive electron-positron-ion (EPI) plasma using Sagdeev pseudo-potential approach.…”

“…The ion acoustic mode, which is an electrostatic mode, will not be considered further in the subsequent part of this manuscript. Now, we proceed further and compare the next higher order terms i.e., ~ 5 2 order terms of equations ( 12) and (14); ~ 2 order terms of equations ( 13) and ( 16) and ∼ò 3 order terms of equation (15) to derive the KdV equation of nonlinear coupled Alfvén and ion-acoustic waves in a magnetized plasma as follows:…”