- 1Key Laboratory of Deep Petroleum Intelligent Exploration and Development, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- 2College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
With the advancement of deep space exploration, conducting electromagnetic (EM) sounding on the Moon is of great significance for investigating the lunar internal structure and the surface EM environment. Since the Moon lacks a global dipole magnetic field and is directly exposed to complex solar wind and Earth's magnetotail environments, clarifying its time-domain response mechanisms to external magnetic perturbations is a prerequisite for lunar surface EM exploration.
This study establishes a homogeneous spherical model to simulate the lunar electromagnetic response to disturbances in the interplanetary magnetic field. By deriving analytical solutions for electromagnetic fields under step excitation (simulating a 10 nT abrupt change in the solar wind), the transient response characteristics for lunar internal electrical conductivities in the range of 10-5 ~10-7S/m are quantitatively analyzed.
The simulation results reveal distinct induction mechanisms:(1) The penetration of the magnetic field is governed by the skin effect. Higher conductivity leads to a stronger shielding effect and a longer rise time to reach the steady state, whereas lower conductivity allows for faster magnetic propagation. (2) The induced electric field exhibits a transient response, with its magnitude inversely proportional to conductivity. Lower conductivity results in a higher instantaneous peak electric field but a faster decay, while higher conductivity suppresses the peak amplitude but extends the signal duration. (3) The induced electric field displays a toroidal symmetry along the latitudes, reaching its maximum at the lunar equator and zero at the poles, with no vertical component.
These findings indicate that electric field detection is particularly suitable for capturing high-frequency transient variations. The derived relationships between signal bandwidth, field intensity, and conductivity provide a theoretical reference for future lunar electromagnetic exploration.
How to cite: Zhang, W., Wang, Z., and Liu, Z.: Time-Domain Simulation and Transient Characteristics of Induced Electromagnetic Fields for Lunar Deep Interior Sounding, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3527, https://doi.org/10.5194/egusphere-egu26-3527, 2026.
