A numerical study of the Schumann resonances in Mars with the FDTD method

Abstract

Natural electromagnetic waves generated near the surface by electrostatic discharges in dust storms (dust devils) or by geological activity could be trapped in the resonant cavity formed by the surface and lower ionosphere of Mars, as it occurs on Earth giving rise to Schumann resonances. The finite difference time-domain technique (FDTD) is applied to model the atmosphere of Mars in order to determine Schumann resonant frequencies, and natural electromagnetic fields at the extremely low frequency range (ELF). A numerical tool is provided to analyze the electrical conductivity profile of the Martian atmosphere, with the aim of obtaining Schumann resonance frequencies and their dependence on various ionization sources and solar activity. The effect of local enhancement of conductivity profile at several altitudes is also studied to understand its consequences on Schumann resonances. A criterion to fix the upper limit of the numerical model is established from these results. Copyright 2007 by the American Geophysical Union.