Evolution of nonlinear magnetosonic waves propagating obliquely to an external magnetic field in a collisionless plasma

It is shown that the asymptotic evolution of finite-amplitude magnetosonic waves propagating obliquely to an external uniform magnetic field in a warm homogeneous plasma is governed by a Kadomtsev-Petviashvili equation having an extra dispersive term. The dispersion is provided by finite-Lamor-radius (FLR) effects in the momentum equation and by the Hall-current and electron-pressure corrections in the generalized Ohm's law. A double-layer-type solution of the equation is obtained, and the equation is shown to reduce to a KdV Burgers equation under certain assumptions.