  Where spatial gradients in the amplitude of an Alfven wave are non-zero, a
nonlinear magnetic-pressure gradient acts upon the medium (the ponderomotive
force). We investigate the nature of such a force in inhomogeneous 2.5D MHD
plasmas by analysing source terms in the nonlinear wave equations for the
general case of inhomogeneous B and {\rho}, and consider supporting nonlinear
numerical simulations. Our equations indicate there are two distinct classes of
ponderomotive effect induced by Alfven waves in general 2.5D MHD, each with
both a longitudinal and transverse manifestation; i) Geometric Effects:
Gradients in the pulse geometry relative to the background magnetic field cause
the wave to sustain cospatial disturbances, the longitudinal and transverse
daughter disturbances - where we report on the transverse disturbance for the
first time. ii) Grad (c_A) Effects: Where a pulse propagates through an
inhomogeneous region (where the non-zero gradients in the Alfven-speed profile
are non-zero), the nonlinear magnetic-pressure gradient acts to accelerate the
plasma. Transverse gradients (phase mixing regions) excite independently
propagating fast magnetoacoustic waves (generalising the result of Nakariakov
et al. 1997, Solar Physics, 175, 93) and longitudinal gradients perturb along
the field (thus creating static disturbances in {\beta} = 0, and slow waves in
{\beta} \= 0).
  We additionally demonstrate that mode conversion due the nonlinear Lorentz
force is a one-way process, and does not act as a mechanism to nonlinearly
generate Alfven waves due to propagating magnetoacoustic waves. We conclude
that these ponderomotive effects are induced by an Alfven wave propagating in
any MHD medium, and have the potential to have significant consequences on the
dynamics of energy transport and aspects of dissipation provided the system is
sufficiently nonlinear and inhomogeneous.
