Solitary kinetic Alfvén waves in a dense electron–positron–ion plasma with degenerate electrons and positrons

Abstract

Through the use of a reductive perturbation technique, solitary kinetic Alfvén waves (KAWs) are investigated in a low but finite b (particle-to-magnetic pressure ratio) dense electron-positron-ion plasma where electrons and positrons are degenerate. The degenerate plasma model considered here permits the existence of sub-Alfvénic compressive solitary KAWs. The influence of r (equilibrium positron-to-ion density ratio), s F (electron-to-positron Fermi temperature ratio), b and obliqueness parameter l z on various characteristics of solitary KAWs are examined through numerical plots. We have shown that there exists a critical value of l z at which a soliton width attains its maximum value which decreases with an increase in r and s. F It is also found that solitons with a higher energy propagate more obliquely in the direction of an ambient magnetic field. The results of the present investigation may be useful for understanding low frequency nonlinear electromagnetic wave propagation in magnetized electron-positron-ion plasmas in dense stars. Specifically, the relevance of our investigation to a pulsar magnetosphere is emphasized.

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

“…u l 1 z 0  + / (in dimensionless form) to be smaller than one suggesting the existence of solitons at sub-Alfvénic speed [40]. 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.…”

“…We seek steady state soliton solution of the KdV equation (35). So, we introduce moving co-ordinate u , 0…”

“…To see the effect of relativistic degeneracy of lighter particles (i.e. electrons and positrons) in comparison to the nonrelativistic degenerate case [35], we draw figures 3 and 4 depicting the nature of variation of width and amplitude of solitary KAWs against positron concentration for different values of electron relativistic degeneracy parameter. We find from these figures that the relativistic degeneracy of electrons and positrons ( p0 h =…”

“…The propagation of electrostatic waves in magnetized dense e-p-i plasma with ultrarelativistic and nonrelativistic degenerate electrons and positrons has been reported in detail by Sadiq et al [9]. Recently, Ahmed and Sah [35] have investigated solitary KAWs in degenerate e-p-i plasma with relevance to a pulsar magnetosphere. In this paper, we propose to study linear KAWs in collisionless relativistic dense e-p-i plasma having low but finite b values, and then investigate small amplitude solitary KAWs therein through the derivation of Kortweg-de Vries (KdV) equation by involving reductive perturbation technique [36].…”

Modulation of kinetic Alfvén waves in an intermediate low-beta magnetoplasma

“…It has been shown that such low-frequency (compared to the ion-cyclotron frequency) KAWs can evolve into intermediate shocks due to the anomalous dissipation, Alfvénic solitons and magnetic kink that are relevant in the solar wind for acceleration of charged particles [8]. Furthermore, the dispersion properties of KAWs and the formation of localized structures, as well as the onset of turbulence have been investigated owing to their applications in space and astrophysical plasmas [2,[9][10][11][12][13].…”