Radiation Field Inside the Homogeneous Moon Excited by a Vertical Magnetic Dipole

Zhu Hong Lin,Shuai S A Yuan,Kai Li

doi:10.1109/access.2022.3147351

Zhu Hong Lin, Shuai S A Yuan + Show 1 more

Open Access

https://doi.org/10.1109/access.2022.3147351

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Abstract

The investigation of radiation field in the moon is important for the moon subsurface detection and vertical magnetic dipoles (VMD) are especially useful as sources and probes. The present work focuses on the radiation field inside the moon excited by a VMD located on or near the moon’s surface. Analytical expressions are derived with approximate method. Contributions of the fields come from two parts: the series expansions of low-order terms using the multiplication iteration method, and the integrals of high-order terms using the asymptotic method. Meanwhile, the field of high-order terms is close to the total field. Compared with the calculation’s direct sum, our method has advantages of accuracy and is suitable for the large-size model. For a source-receiver system on or near the homogeneous moon, it is found the waves propagating inside the moon can be described in terms of ray optics. Based on the formulas, various modes of reflection are taken into account, and the intensity of the primarily reflected waves is calculated numerically. Furthermore, effects of propagation distance and angel, the operating frequency, as well as the height of the source are considered to demonstrate the properties of the field. Particularly, the proposed method and formulas have applications to the moon interior exploration.

Highlights

A S the nearest planet to the earth, the research of the moon contributes essentially to our scientific understanding
According to above derivations and analyses, radiation field components inside the moon excited by a vertical magnetic dipoles (VMD) are studied in detail
The imaginary part of k1 is smaller than the real part, which can be ignored in the low frequency (LF) ranges

Summary

Introduction

A S the nearest planet to the earth, the research of the moon contributes essentially to our scientific understanding. It is imperative to develop space exploration, outline the stratigraphy structure of the lunar subsurface, and detect related parameters of the moon. In the probing of the moon, the radar detection technique has been employed, which was used for the first time during the Apollo 17 mission (Apollo Lunar Sounder Experiment, ALSE) to characterize the lunar structure [1]. Chang’e-3 (CE-3), Chang’e4 (CE-4), and Chang’e-5 (CE-5), the first attempt to survey the moon’s surface using the Lunar Penetrating Radar (LPR), have landed successfully on the moon in 2013, 2018, and 2019, respectively [2]–[4]. Notwithstanding contributions of experiments or the observation data acquired from the lunar [6]–[8], the theoretical treatment for an antenna near the moon’s surface is still lacking, which motivates us to study this problem

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