Low-Noise Fundamental-Mode Orthogonal Fluxgate Magnetometer Built With an Amorphous Ribbon Core

Using dedicated high-frequency measuring system the distribution of the Barkhausen jumps intensity along a reversal magnetization cycle was investigated for low noise fluxgate sensors of various core shapes. It is shown that Barkhausen (reversal magnetization) noise intensity is strongly inhomogeneous during an excitation cycle. In the traditional second harmonic fluxgate magnetometers the signals are extracted in the frequency domain, as a result, some average value of reversal magnetization noises is contributed to the output signals. In order to fit better the noise shape and minimize its transfer to the magnetometer output the new approach for demodulating signals of these sensors is proposed. The new demodulating method is based on information extraction in the time domain taking into account the statistical properties of cyclic reversal magnetization noises. This approach yields considerable reduction of the fluxgate magnetometer noise in comparison with demodulation of the signal filtered at the second harmonic of the excitation frequency.

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Simple Design for Orthogonal Fluxgate Magnetometer in Fundamental Mode

Journal of the Magnetics Society of Japan ◽

10.3379/msjmag.0901rf7129 ◽

2009 ◽

Vol 33 (2) ◽

pp. 43-45 ◽

Cited By ~ 19

Author(s):

I. Sasada ◽

H. Kashima

Keyword(s):

Fundamental Mode ◽

Fluxgate Magnetometer ◽

Simple Design

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DESMEX: A novel system development for semi-airborne electromagnetic exploration

Geophysics ◽

10.1190/geo2019-0336.1 ◽

2020 ◽

Vol 85 (6) ◽

pp. E253-E267 ◽

Cited By ~ 1

Author(s):

M. Becken ◽

C. G. Nittinger ◽

M. Smirnova ◽

A. Steuer ◽

T. Martin ◽

...

Keyword(s):

Magnetic Field ◽

Transfer Functions ◽

System Development ◽

Low Noise ◽

Raw Material ◽

Measurement Unit ◽

Fluxgate Magnetometer ◽

Low Frequencies ◽

Airborne Electromagnetic ◽

Fixed Reference

There is a clear demand to increase detection depths in the context of raw material exploration programs. Semi-airborne electromagnetic (semi-AEM) methods can address these demands by combining the advantages of powerful transmitters deployed on the ground with efficient helicopter-borne mapping of the magnetic field response in the air. The penetration depth can exceed those of classic airborne EM systems because low frequencies and large transmitter-receiver offsets can be realized in practice. A novel system has been developed that combines high-moment horizontal electric bipole transmitters on the ground with low-noise three-axis induction coil magnetometers, a three-axis fluxgate magnetometer, and a laser gyro inertial measurement unit integrated within a helicopter-towed airborne platform. The attitude data are used to correct the time series for motional noise and subsequently to rotate into an earth-fixed reference frame. In a second processing step, and as opposed to existing semi-AEM systems, we transform the data into the frequency domain and estimate the complex-valued transfer functions between the received magnetic field components and the synchronously recorded injection current by regression analysis. This approach is similar to the procedure used in controlled-source EM. For typical source bipole moments of 20–40 kAm and for rectangular current waveforms with a fundamental frequency of approximately 10 Hz, we can estimate reliable three-component (3C) transfer functions in the frequency range from 10 to 5000 Hz over a measurement area of [Formula: see text] for a single source installation. The system has the potential to be used for focused exploration of deep targets.

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Low-noise permalloy ring cores for fluxgate magnetometers

Geoscientific Instrumentation Methods and Data Systems ◽

10.5194/gi-8-227-2019 ◽

2019 ◽

Vol 8 (2) ◽

pp. 227-240 ◽

Cited By ~ 3

Author(s):

David M. Miles ◽

Miroslaw Ciurzynski ◽

David Barona ◽

B. Barry Narod ◽

John R. Bennest ◽

...

Keyword(s):

Magnetic Field ◽

Basic Research ◽

Field Measurements ◽

Low Noise ◽

Space Physics ◽

Local Magnetic Field ◽

Fluxgate Magnetometer ◽

Noise Performance ◽

The 1960S ◽

Or Gate

Abstract. Fluxgate magnetometers are important tools for geophysics and space physics, providing high-precision magnetic field measurements. Fluxgate magnetometer noise performance is typically limited by a ferromagnetic element that is periodically forced into magnetic saturation to modulate, or gate, the local magnetic field. The parameters that control the intrinsic magnetic noise of the ferromagnetic element remain poorly understood. Much of the basic research into producing low-noise fluxgate sensors was completed in the 1960s for military purposes and was never publicly released. Many modern fluxgates depend on legacy Infinetics S1000 ring cores that have been out of production since 1996 and for which there is no published manufacturing process. We present a manufacturing approach that can consistently produce fluxgate ring cores with a noise of ∼6–11 pT per square root hertz – comparable to many of the legacy Infinetics ring cores used worldwide today. As a result, we demonstrate that we have developed the capacity to produce the low-noise ring cores essential for high-quality, science-grade fluxgate instrumentation. This work has also revealed potential avenues for further improving performance, and further research into low-noise magnetic materials and fluxgate magnetometer sensors is underway.

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Double-pass high-gain low-noise EDFA over S- and C+L-bands by tunable fundamental-mode leakage loss

Optics Express ◽

10.1364/oe.15.001454 ◽

2007 ◽

Vol 15 (4) ◽

pp. 1454 ◽

Cited By ~ 11

Author(s):

Chi-Ming Hung ◽

Nan-Kuang Chen ◽

Yinchieh Lai ◽

Sien Chi

Keyword(s):

Fundamental Mode ◽

High Gain ◽

Low Noise ◽

Leakage Loss ◽

Double Pass

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Design of a Low-Cost Small-Size Fluxgate Sensor

Sensors ◽

10.3390/s21196598 ◽

2021 ◽

Vol 21 (19) ◽

pp. 6598

Author(s):

Xiaoyu Shen ◽

Yuntian Teng ◽

Xingxing Hu

Keyword(s):

Low Cost ◽

Amorphous Ribbon ◽

Magnetic Core ◽

Fluxgate Magnetometer ◽

Fluxgate Sensor ◽

Operational Tests ◽

Race Track ◽

New Race ◽

Data Acquisition Module ◽

Geomagnetic Observations

Traditional fluxgate sensors used in geomagnetic field observations are large, costly, power-consuming and often limited in their use. Although the size of the micro-fluxgate sensors has been significantly reduced, their performance, including indicators such as accuracy and signal-to-noise, does not meet observational requirements. To address these problems, a new race-track type probe is designed based on a magnetic core made of a Co-based amorphous ribbon. The size of this single-component probe is only Φ10 mm × 30 mm. The signal processing circuit is also optimized. The whole size of the sensor integrated with probes and data acquisition module is Φ70 mm × 100 mm. Compared with traditional fluxgate and micro-fluxgate sensors, the designed sensor is compact and provides excellent performance equal to traditional fluxgate sensors with good linearity and RMS noise of less than 0.1 nT. From operational tests, the results are in good agreement with those from a standard fluxgate magnetometer. Being more suitable for modern dense deployment of geomagnetic observations, this small-size fluxgate sensor offers promising research applications at lower costs.

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Low-Noise Permalloy Ring-Cores for Fluxgate Magnetometers

10.5194/gi-2019-15 ◽

2019 ◽

Author(s):

David M. Miles ◽

Miroslaw Ciurzynski ◽

David Barona ◽

B. Barry Narod ◽

John R. Bennest ◽

...

Keyword(s):

Magnetic Field ◽

Basic Research ◽

Field Measurements ◽

Low Noise ◽

Space Physics ◽

Local Magnetic Field ◽

Fluxgate Magnetometer ◽

Noise Performance ◽

The 1960S ◽

Or Gate

Abstract. Fluxgate magnetometers are important tools for geophysics and space physics providing high precision magnetic field measurements. Fluxgate magnetometer noise performance is typically limited by a ferromagnetic element that is periodically forced into magnetic saturation to modulate, or gate, the local magnetic field. The parameters that control the intrinsic magnetic noise of the ferromagnetic element remain poorly understood. Much of the basic research into producing low-noise fluxgate sensors was completed in the 1960s for military purposes and was never publicly released. Many modern fluxgates depend on legacy Infinetics S1000 ring-cores that have been out of production since 1996 and for which there is no published manufacturing process. We present a manufacturing approach that can consistently produce fluxgate ring-cores with a noise of ∼6–11 pT per square root Hertz – comparable to many of the legacy Infinetics ring-cores used worldwide today. As a result, we demonstrate that we have developed the capacity to produce the low-noise ring-cores essential for high-quality, science-grade fluxgate instrumentation. This work has also revealed potential avenues for further improving performance, and further research into low-noise magnetic materials and fluxgate magnetometer sensors is underway.

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Search for Martian Schumann Resonances

10.5194/epsc2020-541 ◽

2020 ◽

Author(s):

Yanan Yu ◽

Christopher Russell ◽

Peter Chi ◽

Syed Haider ◽

Jayesh Pabari ◽

...

Keyword(s):

Fundamental Mode ◽

Electromagnetic Waves ◽

Lightning Discharge ◽

Sampling Rate ◽

Dust Storms ◽

Dust Particles ◽

Fluxgate Magnetometer ◽

Electric Discharges ◽

Schumann Resonance ◽

Schumann Resonances

<p>On Earth, electric discharges in thunderstorms produce ELF waves in the Earth-ionosphere waveguide that circles the globe. These waves give rise to Schumann resonances in the waveguide resonant cavity. These waves are also expected to occur at Venus, produced by strong lightning in the Venus atmosphere and at Mars produced by active dust devils or dust storms, during southern hemisphere summer, when the planet is near periapsis. Within dust storms, dust particles undergo triboelectric charging. The charge transfer leads to charge separation. A lightning discharge is expected to occur when the charge exceeds the breakdown strength of the media present. The transient electric discharge emits electromagnetic waves in the VLF/ELF range of frequency, leading to Schumann Resonance in the surface-ionospheric cavity. In a heterogeneous cavity, Schumann resonance modes are observable using an in-situ instrument. Recently has it been possible to search for these electromagnetic waves from the Mars surface using the UCLA-provided InSight fluxgate magnetometer. The weakness of the vertical component of ULF waves at Mars suggests that the subsurface is electrically conducting, allowing trapping of electromagnetic energy between the sub-surface and the ionosphere. The fundamental mode of Schumann resonance carries higher energy compared to there are more chances of observing the fundamental mode. Various values of the first mode are predicted in the literature for Mars like 13-14 Hz or between 9-14 Hz and 17.5 Hz. Even if the fundamental mode is above 10 Hz, the 20 Hz sampling rate will allow detection of an aliased signal. We examine the data obtained during Martian sandstorms for the possible existence of such waves. A large dust storm was detected on Mars beginning on InSight sols 40 to 50, and ending during sols 50 to 90. Examining the 20 Hz InSight magnetometer data during this period reveals no clearly identifiable Schumann Resonance signals within the bandwidth of the magnetometer.</p>

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