Analysis of Primary Field Shielding Stability for the Weak Coupling Coil Designs

Area of Science:

• Geophysics
• Electromagnetism
• Signal Processing

Background:

• Weak coupling coils are crucial for transient electromagnetic (TEM) methods, enhancing signal-to-noise ratio by minimizing mutual inductance.
• Structural instability in aerial or drag-based TEM exploration can lead to primary field leakage, compromising detection reliability.

Purpose of the Study:

• To introduce primary field shielding stability as a critical metric for evaluating weak coupling coil designs.
• To propose a calibration scheme for assessing this shielding stability.
• To quantitatively compare the shielding stability of five typical weak coupling coil designs.

Main Methods:

• Structural optimization of transmitter and receiver coils to reduce mutual inductance.
• Development of a calibration scheme to assess primary field shielding stability.
• Quantitative comparison of shielding stability across five distinct weak coupling coil designs.

Main Results:

• Identified structural instability as a source of primary field leakage in aerial/drag TEM.
• Established a method for quantitatively assessing primary field shielding stability.
• Demonstrated significant differences in shielding stability among various weak coupling coil designs.

Conclusions:

• Shielding stability is a vital consideration for weak coupling coil design in TEM.
• The proposed calibration scheme provides a reliable method for assessing coil stability.
• Findings can guide the selection and improvement of TEM coils for enhanced detection reliability.