Solitary kinetic Alfven waves in a dense electron-positron-ion plasma with degenerate electrons and positrons

Through the use of a reductive perturbation technique, solitary kinetic Alfven waves (KAWs) are investigated in a low but finite beta (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-Alfvenic compressive solitary KAWs. The influence of r (equilibrium positron-to-ion density ratio), sigma(F) (electron-to-positron Fermi temperature ratio), beta 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 sigma(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.