With new high power lasers it is becoming increasingly obvious that fluid based models of laser plasma interaction miss many operationally important interactions. An example is the possibility that trapped electrons may allow for the existence of an undamped electron acoustic waves (EAWs). SRS of such waves can lead to scattering of the incoming EM laser fields beyond the quater critical surface and at different backscatter intensities and frequencies than expected from fluid theory. Understanding such interactions can therefore lead to a better predictive capability for SRS backscatter and also aid the interpretation of experimental results. This work is currently underway at Warwick via both direct Vlasov solvers and PIC codes.