Field trial of an electrically passive optical-fiber magnetometer.

Area of Science:

• Geophysics
• Sensor Technology
• Electromagnetism

Background:

• Geomagnetic surveying is crucial for understanding Earth's magnetic field.
• Transient electromagnetic (TEM) methods are widely used in geophysical exploration.
• Developing sensitive and passive magnetic field sensors is an ongoing challenge.

Purpose of the Study:

• To describe a field trial of an electrically passive optical-fiber magnetometer.
• To evaluate its integration with the transient electromagnetic (TEM) method for geomagnetic surveying.
• To assess the performance of the novel magnetometer in measuring magnetic field decay rates.

Main Methods:

• An optical-fiber magnetometer utilizing a metallic glass wire core was developed.
• The magnetometer transducer was integrated into a TEM surveying system.
• The sensor's capability to measure the decay rate of the surface magnetic field was tested.

Main Results:

• The optical-fiber magnetometer successfully measured magnetic field decay rates during the field trial.
• The sensor demonstrated a minimum detectable magnetic field of 2.5 × 10(-8) G/√Hz at 2 kHz.
• The electrically passive nature of the magnetometer simplifies its integration into existing surveying techniques.

Conclusions:

• The described optical-fiber magnetometer is a viable tool for geomagnetic surveying using TEM methods.
• The sensor's sensitivity and passive design offer advantages for geophysical applications.
• Further development could enhance its application in various magnetic field measurement scenarios.