This study will investigate a source mechanism generating ion acoustic wave turbulence in the topside ionosphere that can cause strong backscatter radar echoes leading to false satellite detection signals. Theoretical investigation of the problem will be conducted at MIT, while field experiments are planned at the Arecibo Observatory to simulate the ionospheric conditions for the generations of ion acoustic wave turbulence. The proposed source mechanism is a nonlinear mode coupling process whereby Langmuir waves induced by particle precipitation can interact nonlinearly to produce ion acoustic mode waves. Detailed formulation of this nonlinear interaction process will be carried out, incorporating realistic energy spectra of high particles with a numerical analysis. In the simulation experiments at Arecibo, the VLF waves induced in the ionosphere by the HF heater are expected to cause the pitch angle scattering of originally trapped electrons in the radiation belts. These suprathermal electrons precipitated into the ionosphere along the earth's magnetic field will form a potential source producing large amplitude ion acoustic waves. Both the 430 MHz and 50 MHz radars will be employed to diagnose the ionoaphere over Aercibo. The Aercibo experiments will be conducted primarily in the 1991 ionosphere heating campaign for the dedicated research program.
