Electron beam transport in the ionosphere - energy deposition and optical emissions based upon the combined effects of plasma turbulence and particle-particle interactions. Final report Jan-Dec 81

The problem of electron beam propagation in the E-region is examined. A model is developed to describe that part of beam spreading due to plasma turbulence. The basis of the model is that the given turbulence can cause a series of effective displacements delta r(GC) of the beam electron guiding centers through a corresponding series of briefly experienced perpendicular components of the turbulent electric field. Weak turbulence theory is considered and applied to cases of warm and cold beams. A Monte Carlo code has been developed to follow the spreading of the beam electron guiding centers where delta r(GC) is given altitude dependence. An analytic expression is used when delta r(GC) is constant with altitude. The turbulence model is used to examine beam spreading as observed by Davis et al. (1971) and Hallinan et al. (1978). We can generally account for the observed amount of spreading by adding in the contribution due to particle-particle interactions. Optical properties associated with beam energy deposition are also modeled. Most features in the UV and visible portion of the optical spectrum are considered along with their emission efficiencies.