The plasma response to a strong high−frequency electric field has been reformulated in a way that shows that the basic nonlinear parameter is &agr; = &Lgr;&eegr;0(&ohgr;p/&ohgr;0)2, where &Lgr; is essentially the number of particles in a Debye sphere and &eegr;0=E0(4&pgr;n0kBT)−1/2is the usual electric field parameter. Numerical integration has produced results which show such phenomena as locally increased absorption, lower dissipation rates for strong fields, and somewhat deeper penetration of the electromagnetic wave turning point (compared with weak field results).