Spectral-element-based radar modeling: An application to Asteroid imaging.

Abstract

Imaging the interior structure of asteroids, comets, and other Near Earth small body structures could play a significant role in the scientific community’s understanding of the Solar system. Accurate imaging of near-Earth objects (NEOs) can in principle be achieved by using Seismic or Radar Systems. In this project, the use of a dual-orbiting Radar System is advocated, which is based on the radiation of electromagnetic waves. This dual-orbiting setup, involves two orbiters around the target model (sources and receivers), acquiring data without landing on the target. We demonstrate a 2D imaging method on a complex asteroid model, which is a good approximation of the asteroid 433 Eros. Using synthetic models, we simulate multiple electromagnetic sources and set up a Reverse Time Migration (RTM) algorithm as an asteroid imaging application. Honoring the complex structure of an asteroid while accounting for the strong contrast in electromagnetic parameters hinders the implementation of standard finite difference solvers in this context. Therefore, for the modeling part, we opt for a high-order finite spectral element method, as it is considered as one of the most efficient numerical approaches to solve wave propagation problems of high computational demand. This general workflow is implemented using the Salvus framework developed by Mondaic AG. Here, we set a specific parameterization that allows us to solve the telegraph equation within the seismic-oriented salvus engine. Finally, we show multiple asteroid structural images reconstructed from different acquisition setups to distinguish their main characteristics and implications for subsequent studies. For more expensive computations, we make use of a cluster HPC environment