LARGE ASPECT ANGLES IN AURORAL E-REGION ECHOES - A SELF-CONSISTENT TURBULENT FLUID THEORY

We use a recently formulated fluid theory of turbulent Farley-Buneman waves to study the impact of anomalous transport coefficients on the a spect angles of large-amplitude waves in the high-latitude E region in the strong nonlinear regime. The theory is self-consistent and contai ns all the nonlinearities of the system except for the generation of u nstable secondary waves through a two-step process, which has been stu died elsewhere. Our study leads us to conclude that nonlinear processe s are responsible for an increase in the aspect angles of large-amplit ude waves through an increase in the scattering of electrons in the di rection parallel to the geomagnetic field in conjunction with a lack o f any significant increase in the scattering of electrons by waves in the plane perpendicular to the geomagnetic field.