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

Through the use of a reductive perturbation technique, solitary kinetic Alfvén waves (KAWs) are investigated in a low but finite β (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), σ_F (electron-to-positron Fermi temperature ratio), β 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 σ_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.