High Fidelity Sporadic E Model

Program Objectives: The objective of this solicitation is to develop a high-fidelity sporadic-E model that is useful for and can be integrated into currently accepted and deployed ionospheric-modeling and ray-tracing tools. “High fidelity” in this context refers to a 3-dimensional (3D) model that is spatially and temporally on the order of the development of the key features of sporadic E, consistent with high-resolution Incoherent Scatter Radar (ISR) observations. The intention is to use results from this model to develop and update operational ionospheric-propagation codes used by the Space Force in modeling and tracking ISR performance and communication. Description of Effort: NWRA has developed a sporadic-E model based on coupled gravity-wave and wind-shear dynamics observed to occur in the ionosphere and simulated by Dr. Werne, using his high-resolution spectral DNS (Direct Numerical Simulation) fluid-dynamics solver, currently running on a host of DoD HPC platforms. By adding a magnetic field and tracking and interpreting the resulting motions of ions, Dr. Werne has been able to reproduce key observed ISR temporal and spatial features. The proposed effort a) extends existing 2D results to 3D, and evaluates the feasibility of b) simulating a suite of 3D cases that explore relevant ionospheric conditions, across the globe and through a variety of solar conditions, and c) assessing the consequences of the modeled sporadic E using existing ionospheric-propagation codes developed by NWRA. The focus of the work in this proposed effort is to use DNS to understand the small-scale structuring within sporadic-E layers (10m - 10km irregularity scale sizes) due to instability processes, with the intention of using this understanding in the development of a small-scale structure component in the Es models under development by us in two parallel AFRL efforts (SEEM Calls 007 and 009).