Shear Alfvén wave density dips in electron-positron-ion plasmas

Abstract

Nonlinear kinetic Alfvén waves are studied in an electron-positron-ion plasma. It is noticed that the nonlinearity and Larmor radius effects can compromise to give rise to density dips in such plasmas in the super Alfvénic regime. A comparison is presented with previous results, which predict density humps in such plasmas if ion inertial effects parallel to the external magnetic field are taken into account.