  Using high resolution Vlasov - Poisson simulations, evolution of driven
``cold" electron plasma wave (EPW) in the presence of stationary inhomogeneous
background of ions is studied. Mode coupling dynamics between ``cold'' EPW with
phase velocity $v_{\phi}$ greater than thermal velocity i.e $v_{\phi} \gg
v_{thermal}$ and its inhomogeneity induced sidebands is illustrated as an
initial value problem. In driven cases, formation of BGK like phase space
structures corresponding to sideband modes due to energy exchange from primary
mode to bulk particles via wave-wave and wave-particle interactions leading to
particle trapping is demonstrated for inhomogeneous plasma. Qualitative
comparison studies between initial value perturbation and driven problem is
presented, which examines the relative difference in energy transfer time
between the interacting modes. Effect of variation in background ion
inhomogeneity amplitude as well as ion inhomogeneity scale length on the driven
EPWs is reported.
