A simple yet novel rf exciter structure has been developed for generating remotely intense rf fields in a magnetoplasma. It is a circular line source of radiusRin a plane ⊥B0driven with an rf signal at &ohgr; <&ohgr;c≃&ohgr;p(where &ohgr;c, &ohgr;pare the electron cyclotron and electron plasma frequency, respectively) which excites two resonance cones with focal points atz=±Rcot&THgr;c(&THgr;cis the cone angle). The rf intensity increasesawayfrom the exciter to reach a maximum (approximately 20 dB enhancement) at the remote focal points. This arrangement is ideally suited to study nonlinear interactions free of boundary effects. At large applied rf signals, &egr;0Erf2/nkTe≳0.2, a strong density depression in the focal region (&dgr;n/n≳40%) is observed. The density perturbation modifies the cone angle and field distribution. This nonlinear interaction leads to a rapid growth of ion acoustic wave turbulence and a corresponding random rf field distribution in a broadened focal region. The development of the interaction is mapped in space and time.