Finite element analysis for nightside transfer function lunar electromagnetic induction studies

Autor: I. de Pater, H. Fuqua Haviland, G. T. Delory
Rok vydání: 2019
Předmět:
Zdroj: Advances in Space Research. 64:779-800
ISSN: 0273-1177
DOI: 10.1016/j.asr.2019.05.006
Popis: The global electromagnetic induction response of the Moon has been solved numerically for several electrical conductivity profiles using the finite-element method. Here we demonstrate the capability and applicability in both two and three spatial dimensions for any input magnetic field time series measured at the Moon. We discuss the applicability of a vacuum approximation to the induced magnetic field response to the lunar plasma environment and the challenges of isolating geomagnetic induced fields including the interaction with the lunar wake structure. We perform three validation analyses comparing our vacuum model response to analytic solutions: (1) the time domain response to a step impulse or tangential discontinuity within the solar wind, (2) the time domain response to a ramp driving function, and (3) the broadband frequency domain response. We fit the analytic solutions to a root-mean-square error of better than 1% for all cases. We analyze the accuracy range and demonstrate our model’s capability of resolving interior structure from Apollo magnetometer data. We present the first time domain numerical solution of the induced magnetic field response of the Moon in vacuum for any driving input signal and any interior conductivity profile, building on previous Apollo era work. Lastly, we discuss the trade-offs between model accuracy and performance, which is of particular concern for large datasets and iterative optimizations. The transfer function method developed here is applicable to other airless body two-point magnetometer measurements including Apollo, ARTEMIS, and future lunar geophysical networks.
Databáze: OpenAIRE
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