Particle-in-cell Simulations of Electromagnetic Wave Scattering From Numerically Generated Flute-type Density Irregularities

Abstract:

The propagation of electromagnetic (EM) waves can be influenced by the presence of plasma turbulence. It is known that Flute-type density irregularities can develop during the nonlinear stage of an interchange instability in Earth’s ionosphere and can affect radio communication channels. These density structures play an important role in the refraction and scattering of EM waves in Earth’s ionosphere and also in laser diagnostic scattering experiments. To generate Flute-type density irregularities, we will use previously obtained numerical solution of nonlinear fluid equations involving the electrostatic potential and density. The solutions to these fluid equations govern the development of an interchange instability and results in the spatial dependence of density irregularities which can be used to analyze scattering of high frequency EM waves. This solution contains both large scale vortex density structures coexisting with short scale density perturbations. Next we will initialize a PIC simulation with the density structure from the fluid simulation to calculate the scattering cross-section and compare the results with an analytic solution obtained using numerically calculated density spectra. Because the linear and non-linear stages are well separated in time, we will compare the effect of scattering from density irregularities which form in both the linear and non-linear stages.