scholarly journals Contributors to Fluxgate Magnetic Noise in Permalloy Foils Including a Potential New Copper Alloy Regime

2021 ◽  
Author(s):  
David M. Miles ◽  
Richard Dvorsky ◽  
Kenton Greene ◽  
Christian Hansen ◽  
B. Barry Narod ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Copper Alloy ◽  
Low Frequency ◽  
Magnetic Field Measurement ◽  
Physical Parameters ◽  
Magnetic Noise ◽  
Ramp Rate ◽  
Vector Magnetic Field ◽  
Empirical Experiment ◽  
Ring Core

Abstract. Fluxgate magnetometers provide sensitive and stable measurements of the static and low frequency vector magnetic field. Fluxgates form a magnetic field measurement by periodically saturating a ferromagnetic core and the intrinsic magnetic noise of this material can determine the noise floor of the instrument. We present the results of an empirical experiment to understand the physical parameters that influence the intrinsic magnetic noise of fluxgate cores. We compare two permalloy alloys – the historical standard 6 % molybdenum alloy and a new 28 % copper alloy. We examine the influence of geometry using the historical standard 1” diameter spiral wound ring-core and a new stacked washer racetrack design. We evaluate the influence of material thickness by comparing 100 µm and 50 µm foils. Finally, we investigate heat treatments in terms of temperature and ramp rate and their role in both grain size and magnetic noise. The results of these experiments suggest that thinner foils, potentially comprising the copper alloy, manufactured into continuous racetrack geometry washers may provide excellent performance in fluxgate sensors.

Vector magnetic field measurement based on magnetic fluid and high-order cladding-mode Bragg grating

2021 ◽  
Vol 143 ◽  
pp. 107264
Author(s):  
Junying Zhang ◽  
Fengyi Chen ◽  
Ruohui Wang ◽  
Xueguang Qiao ◽  
Haibin Chen ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fluid ◽  
Field Measurement ◽  
High Order ◽  
Bragg Grating ◽  
Magnetic Field Measurement ◽  
Vector Magnetic Field ◽  
Cladding Mode

Physics of Flexible Magnetic Filaments

2011 ◽  
Vol 222 ◽  
pp. 221-224 ◽  
Author(s):  
Ivars Javaitis ◽  
Vineta Zilgalve
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Coefficient Of Friction ◽  
Low Frequency ◽  
Rotating Magnetic Field ◽  
Physical Parameters ◽  
Filament Dynamics ◽  
Field Coefficient ◽  
Stable Shape

A model of elastic magnetic filaments is developed, which allows investigating the dependence of filament dynamics on such physical parameters as magnetoelastic number (Cm), frequency of magnetic field, coefficient of friction, etc. By numerical simulation of the dynamics of filament shaping under the action of magnetic field it is shown that a characteristic U-like stable shape (hairpins) can form. Such a shape of filament can exist in the case of low-frequency rotating magnetic field. At the frequency increasing the U-like shape transforms to the S-like one. In the present work it is shown that in unsteady magnetic field a flexible magnetic filament “swims” in the direction of magnetic field.

scholarly journals The Application of Low-Frequency Transition in the Assessment of the Second-Order Zeeman Frequency Shift

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8333
Author(s):  
Yang Bai ◽  
Xinliang Wang ◽  
Junru Shi ◽  
Fan Yang ◽  
Jun Ruan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Frequency Shift ◽  
Low Frequency ◽  
Pulse Signal ◽  
Second Order ◽  
Magnetic Field Measurement ◽  
Central Frequency ◽  
Zeeman Frequency ◽  
The Magnetic Field ◽  
Frequency Pulse

Second-order Zeeman frequency shift is one of the major systematic factors affecting the frequency uncertainty performance of cesium atomic fountain clock. Second-order Zeeman frequency shift is calculated by experimentally measuring the central frequency of the (1,1) or (−1,−1) magnetically sensitive Ramsey transition. The low-frequency transition method can be used to measure the magnetic field strength and to predict the central fringe of (1,1) or (−1,−1) magnetically sensitive Ramsey transition. In this paper, we deduce the formula for magnetic field measurement using the low-frequency transition method and measured the magnetic field distribution of 4 cm inside the Ramsey cavity and 32 cm along the flight region experimentally. The result shows that the magnetic field fluctuation is less than 1 nT. The influence of low-frequency pulse signal duration on the accuracy of magnetic field measurement is studied and the optimal low-frequency pulse signal duration is determined. The central fringe of (−1,−1) magnetically sensitive Ramsey transition can be predicted by using a numerical integrating of the magnetic field “map”. Comparing the predicted central fringe with that identified by Ramsey method, the frequency difference between these two is, at most, a fringe width of 0.3. We apply the experimentally measured central frequency of the (−1,−1) Ramsey transition to the Breit-Rabi formula, and the second-order Zeeman frequency shift is calculated as 131.03 × 10−15, with the uncertainty of 0.10 × 10−15.

Vector Magnetic Field Measurement of NOAA AR 10197

2006 ◽  
Vol 6 (4) ◽  
pp. 470-476 ◽  
Author(s):  
Hong-Fei Liang ◽  
Hai-Juan Zhao ◽  
Fu-Yuan Xiang
Keyword(s):  
Magnetic Field ◽  
Field Measurement ◽  
Magnetic Field Measurement ◽  
Vector Magnetic Field

scholarly journals Localization of Alternating Magnetic Dipole in the Near-Field Zone with Single-Component Magnetometers

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Gao Xiang ◽  
Du Bo-cheng ◽  
Wang Qi-long
Keyword(s):  
Magnetic Field ◽  
Magnetic Dipole ◽  
Near Field ◽  
Vertical Component ◽  
Low Frequency ◽  
Single Component ◽  
Dipole Source ◽  
Magnetic Field Measurement ◽  
Field Zone ◽  
Theoretical Simulation

Tri-axis magnetometers are widely used to measure magnetic field in engineering of the magnetic localization technology. However, the magnetic field measurement precision is influenced by the nonorthogonal error of tri-axis magnetometers. A locating model of the alternating magnetic dipole in the near-field zone with single-component magnetometers was proposed in this paper. Using the vertical component of the low-frequency magnetic field acquired by at least six single-component magnetometers, the localization of an alternating magnetic dipole could be attributed to the solution for a class of nonlinear unconstrained optimization problem. In order to calculate the locating information of alternating magnetic dipole, a hybrid algorithm combining the Gauss–Newton algorithm and genetic algorithm was applied. The theoretical simulation and field experiment for the localization of alternating magnetic dipole source were carried out, respectively. The positioning result is stable and reliable, indicating that the locating model has better performance and could meet the requirements of actual positioning.

scholarly journals Range Detection of the Extremely Low-Frequency Magnetic Field Produced by Laptop’s AC Adapter

2017 ◽  
Vol 17 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Darko Brodić ◽  
Alessia Amelio
Keyword(s):  
Magnetic Field ◽  
Low Frequency ◽  
Operating Conditions ◽  
Magnetic Field Measurement ◽  
Field Exposure ◽  
Heavy Load ◽  
Safety Standards ◽  
Extremely Low Frequency ◽  
Frequency Magnetic Field ◽  
The Magnetic Field

Abstract Human exposure to extremely low frequency magnetic field represents a risk to their health. This paper takes into consideration the level of an extremely low-frequency magnetic field between 30 and 300 Hz emitted by an AC laptop adapter. The experiment consists of testing 17 different AC adapters for laptops. During the testing, laptops are operated in a normal operating conditions as well as under heavy load. The magnetic field measurement is conducted in the area around the AC adapter. Obtained data is evaluated according to the critical level of the magnetic field proposed by safety standards. Furthermore, data is classified by a K-medians method in order to determine the critical levels of the magnetic field exposure in the nearby area of the AC adapter. Obtained classifications are evaluated according to safety standards, giving a critical analysis of magnetic field areas at risk. Due to emission of a very strong magnetic field in certain areas, a recommendation for safety use of the AC adapter is proposed.

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