  Nonlinear set of equations for inertial or slow shear Alfven wave (SSAW) in
ideal electron-positron-ion (e-p-i) plasmas are presented. The analytical
solution for arbitrary amplitude SSAW in such multi-component plasmas is
obtained using Sagdeev potential approach. The numerical solutions for several
different cases have also been presented for illustrative purpose. It is found
that the electron density dips of SSAW are formed in the super Alfvenic region.
The amplitude and the width of the nonlinear shear Alfven wave reduces with the
increase in the concentration of positrons in electron-ion (e-i) plasmas. The
width of the soliton also depends upon the direction of propagation of the
perturbation in both e-i and e-p-i plasmas.
