The nonlinear propagation of a lower hybrid (l.h.) disturbance in unif
orm and nonuniform plasmas is computed, consistently with the finite a
mplitude density modifications due to the ponderomotive forces origina
ted by the radio frequency (r.f.) power itself. Strong spectral broade
ning is shown to occur due to the coupling with magnetized acoustic wa
ves. (C) 1997 Elsevier Science B.V.