Parallelization of 3-D Global FDTD Earth-Ionosphere Waveguide Models at Resolutions on the Order of ∼1 km and Higher

Three-dimensional finite-difference time-domain (FDTD) models of the global Earth-ionosphere waveguide were first introduced in the early 2000s. These models have been applied to a wide variety of applications at ultralow and extremely low frequencies, including hypothesized earthquake precursors, Schumann resonances, and space weather hazards to electric power grids. The deployment of petascale supercomputers and future plans for exascale supercomputers introduce for the first time the possibility of generating ultrahigh-resolution FDTD models of the Earth-ionosphere waveguide at 1 km and higher globally. When including a magnetized ionospheric plasma algorithm, these models may simulate very low frequencies for the first time on a global scale and/or extend to altitudes well above 100 km as needed. We describe the parallelization strategy of efficient latitude-longitude FDTD Earth-ionosphere models and describe some example performances on the Blue Waters supercomputer, which has over 360 000 computational cores.