Range Of Magnetic Field Intensities Research Articles

An ultra-sensitive photonic crystal fiber magnetic field sensor based on Vernier effect using two parallel Sagnac loops

Magnetic field detection is of significant importance in various fields, including military, industrial, and power transmission systems. In this paper, we propose a novel ultra-sensitive photonic crystal fiber (PCF) magnetic field sensor based on the Vernier effect, employing two parallel Sagnac loops. Since magnetic field detection relies on the magneto-optical effect of magnetic fluids, all air holes in the PCF are assumed to filled with magnetic fluids. By inserting two slightly different lengths of PCFs into two parallel Sagnac loops, the Vernier effect can be excited to improve the sensitivity of magnetic field detection. The sensing characteristics of the PCF magnetic field sensor are theoretically studied using the finite element method (FEM). Moreover, the influences of the wavelength and magnetic field intensity on the sensing performance are also analyzed. The results show that the sensitivity and resolution of the PCF magnetic field sensor can reach 11.9 nm Oe−1 and 8.4 × 10−3 Oe, respectively, within the magnetic field intensity range of 80–150 Oe. To our best knowledge, the proposed magnetic field sensor exhibits the highest sensitivity among existing magnetic field sensors based on optical fiber interferometers. The proposed magnetic field sensor possesses ultra-high sensitivity and resolution, which exhibits good application prospects in the field of magnetic field detection.

Reflective magnetic field and temperature dual-parameter sensor based on no-core fiber probe

A kind of reflection-type magnetic field and temperature dual-parameter sensor based on surface plasmon resonance (SPR) effect was proposed and investigated. The sensing probe was fabricated with a section of no-core fiber, which was evenly divided into two parts. One part was immersed in magnetic fluid (MF) for magnetic field sensing (Channel 1, referred as CH1). The other part was coated with polydimethylsiloxane (PDMS) for temperature sensing (Channel 2, referred as CH2). The issue of magnetic field and temperature cross-sensitivity was resolved ingeniously. In the magnetic field intensity range of 0–55.1 mT, the maximum magnetic field sensitivity of 122.67 pm/mT was obtained. In the temperature range of 30–70 ℃, the maximum temperature sensitivity was 1662.64 pm/◦C. The sensor has the advantages of simple structure, small size, and potentials for applications in narrow space.

Ampere force fiber optic magnetic field sensor using a Fabry-Perot interferometer.

The paper presents a novel fiber-optic vector magnetic field sensor using a Fabry-Perot interferometer, which consists of an optical fiber end face and a graphene/Au membrane suspended on the ceramic ferrule end face. A pair of gold electrodes are fabricated on the ceramic ferrule by femtosecond laser to transmit electrical current to the membrane. Ampere force is generated when an electrical current flows through the membrane in a perpendicular magnetic field. The change in Ampere force causes a shift in the resonance wavelength in the spectrum. In the magnetic field intensity range of 0 ∼ 180 mT and 0 ∼ -180 mT, the as-fabricated sensor exhibits magnetic field sensitivity of 5.71 pm/mT and 8.07 pm/mT. The proposed sensor has great potential application in weak magnetic field measurements due to its compact structure, cost-effectiveness, ease to manufacture, and good sensing performance.

Theoretical Investigation of Strain-Adjustable Ge0.92Sn0.08 Light-Emitting Diodes With Giant Magnetostrictive Stressor for Short-Wave Infrared Light Source

A new idea was provided by the group-IV GeSn alloys for short-wave infrared light source compatible with CMOS due to the low cost integrated on the Si platform and can be transformed into direct bandgap alloy. More than 7.1% Sn content or strain engineering is used to achieve the direct bandgap GeSn semiconductors and enhance the luminous efficiency of GeSn light-emitting devices. We theoretically investigate a strain-adjustable GeSn light-emitting diode with the giant magnetostrictive stressor. A 0∼0.11% adjustable uniaxial tensile strain is introduced into Ge <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.92</sub> Sn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.08</sub> LED by adjusting the external magnetic field. A continuously adjustable bandgap from 0.543 eV to 0.475 eV of the Ge <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.92</sub> Sn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.08</sub> alloy is achieved in the magnetic field intensity range of 0∼240 kA/m, and the spontaneous emission rate of the strained LED is enhanced about 3.63 times compared with the relaxed device. Besides, an adjustable range of luminous peak is achieved from 2.18 μm to 2.46 μm, which can promote the application of GeSn light source for magnetic field detection and photo-communication in short-wave infrared.

Solving Magnetodynamic Problems via Normal Form Method

Closed-form formulations are difficult to find when the material behavior law is nonlinear. A linear approximation, on the other hand, has a very narrow range of validity. In this communication, the normal form (NF) method is used to solve a 1-D nonlinear magnetodynamic problem. The discrete model is formulated in a state-space form suitable for NF applications. The resulting system is then expanded on a linear mode basis to cubic order. Analytical solutions are obtained using the NF technique and compared with traditional solutions. The results show that the cubic polynomial adequately approximates the problem, and the NF solution is valid for some range of magnetic field intensity.

High-Sensitivity Magnetic Field Sensor Based on Long-Period Grating Near the Dispersion Turning Point

We demonstrate the fabrication of a high-sensitivity magnetic field sensor based on the packaged long-period fiber grating (LPFG) with magnetic fluid. The transmission spectra and the surrounding refractive index (SRI) characteristics of the LPFGs near the dispersion turning point (DTP) were investigated theoretically and experimentally. We have studied the influence of mode order and wavelength separation at DTP on the SRI sensitivity of the DTP-LPFG. The experimental results are consistent with the simulation. The LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0,10</sub> mode has the highest SRI sensitivity of 1956.4 nm/RIU in the range of 1.333-1.435 when the wavelength separation at DTP is 89.1 nm. The sensor achieves a magnetic field sensitivity of 1.9 nm/mT in the magnetic field intensity range of 0-20.5 mT, which indicates that the sensor can be used as a high-sensitivity magnetic field sensor.

Reflective fiber-optic magnetic field sensor based on a magnetic-fluid-filled capillary probe structure

A novel reflective magnetic field sensor is presented and experimentally demonstrated. The sensing probe is fabricated by splicing a section of uncoated four-core fiber (FCF) between two sections of no-core fibers (NCFs), and the end face of the last NCF is coated by silver. The sensor structure is sealed in a magnetic fluid (MF)-filled capillary, so that the NCF–FCF–NCF magnetic field sensing probe structure is obtained. The NCF is used to excite the high-order modes of the FCF’s cladding. Combined with the adjustable refractive index of MF, the sensor is sensitive to the magnetic field and temperature. Experimental results indicate that the presented sensor can measure the low magnetic field and high magnetic field. In the low magnetic field ranges of 0–10 mT and 10–18 mT, the wavelength near 1548 nm varies linearly with the magnetic field intensity, and the sensitivities are −7.43 pm mT−1 and −60 pm mT−1, respectively. The sensitivity of the interference intensity is −0.30782 dB mT−1 in the low magnetic field intensity range of 0–18 mT. The sensor under low magnetic field is also affected by temperature. In the temperature range of 20 °C–70 °C, the temperature sensitivity of the wavelength shift around 1548 nm is 62.33 pm °C−1, and the corresponding sensitivities of the interference intensity are −0.03888 dB °C−1 and −0.02076 dB °C−1 in the range of 30 °C–50 °C and 50 °C–70 °C, respectively. However, the effect of temperature on the sensor in the high magnetic field (18–36 mT) can be ignored. Within the high magnetic field intensity range of 26–36 mT, the sensitivity of the interference intensity near 1598 nm is −1.20993 dB mT−1. The dual-parameter matrix is used to eliminate the cross-sensitivity of temperature in the low magnetic field. This sensor, with the advantages of easy fabrication, high sensitivity and low cost, has the potential application in the magnetic field monitoring.

Magnetic sensor based on WGM hollow microbubble resonator filled with magnetic fluid

In this work, a magnetic sensing scheme based on whispering gallery mode (WGM) hollow microbubble resonator (HMR) filled with magnetic fluid (MF) is proposed. The HMR is made by the pressure-assisted arc discharge method on the microcapillary. WGM is excited by evanescent fields in HMR. The quality factor of resonator is 4.02×106. Then, the influence of the wall thickness of HMR and the concentration of MF on the sensor is studied both theoretically and experimentally. When MF is infiltrated in the HMR, the refractive index (RI) of the MF increases with the increase of the magnetic field intensity, resulting in the shift of the resonance wavelength. By reducing the wall thickness, the magnetic sensing sensitivity is increased from 2.6 pm/mT to 25.21 pm/mT within the magnetic field intensity range of 2 mT–20 mT. In addition, the increase in the concentration of MF and the clustering phenomenon caused by it have also been observed. This work provides a novel magnetic sensing scheme, and the proposed WGM resonator has great application prospects in optofluidic sensing.

Влияние нелинейности закона намагничивания феррожидкости на неустойчивость Кельвина--Гельмгольца

We study Kelvin-Helmholtz instability which develops when a homogenous gas flow is moving over a horizontal surface of a ferrofluid of given physical properties moving in the same direction, in presence of a homogeneous magnetic field parallel to this direction. Magnetic field intensity range includes the values that correspond to the interval where magnetization curve reaches magnetization saturation level. Stability area is constructed in the “magnetic field intensity – dimensionless relative velocity of fluids” parameter plane.

Interpretation of Aeromagnetic Data over the Nigerian Sector of the Mamfe Basin

Four Aeromagnetic data over a part of the Nigerian Sector of the Mamfa Basin have been analyzed using qualitative approach and spectral analysis. The aeromagnetic maps, its analytic signal amplitude and geological modelling sketch helped in identifying the nature and depth of the magnetic sources in the study region. The qualitative interpretation reveals that the study area is characterized by magnetic lineament trend in NE-SW direction and subordinate E-W direction. The results obtained are in line with the trend of the Benue Trough. The aeromagnetic maps reveal that the sedimentary thickness increases towards the northern parts of the study area. The results also reveal that the total magnetic field intensity range from 7800 to 8290 nanotesla (nT) in the study area. The residual anomaly map reveals that the maximum anomaly value is 160nT which is found around Bansara and Ugep environs while the minimum magnetic value is -140nT towards the Abakiliki and Ikom areas. Results from spectral analysis indicated two magnetic source depths, which account for deeper and shallower sources. The deeper magnetic sources vary from 2.76 km near Abakiliki to 5.37 km near Bansara, whereas the shallow magnetic sources vary from 0.58 km near Ikom to 1.76 km near Ugep. The depth to basement map reveals that the sediment thickness increases towards the northern parts of the study area. The depths to basement are deeper in the northern and central parts trending northwest-southeast direction and shallower in the eastern and southern parts of the study area. The result also shows a linear depression with sedimentary accumulation trending northwest-southeast. The temperatures at depth for each anomaly block were estimated to range between 48.46 and 225.69°C with an average of 117.04°C. Based on the computed sedimentary thickness (2.76-5.37km) and temperature at depth (62-220°C), the possibility of hydrocarbon generation in the northern and central parts of the study area is realistic

A Molecular Dynamics Simulation of the Toluene-Water Interface in the Presence of an External Magnetic Field

Among the current techniques in the stabilizing the emulsion, the magnetic treatment is attracting more attention during past years. In this work, a molecular dynamics simulation was performed to investigate the effect of an external magnetic field on the toluene-water interface. An extended version of Nanoscale Molecular Dynamics (NAMD) source code including the magnetic field feature was used to do all MD calculations. The radial distribution function (RDF), the integration RDF, and the non-bonded energy of three pairs atoms, beside the interfacial tension (IFT) values in the presence of different magnetic field intensities have been calculated and reported in this paper. The changes in the potential of the interaction has been proved by analyzing the RDF and integration RDF plots. The obtained results showed that the increase of IFT is only appeared within a specific range of magnetic field intensities. Moreover, the IFT decreases when the magnetic field intensity is increased. The simulation results provide an elementary understanding of the applying magnetic treatment as a technique in the preparing of emulsion system.

Quantum state preparation of hydrogen atoms by hyperfine quenching

We discuss the use of a region of uniform and constant magnetic field in order to implement a two-state atomic polarizer for an H(2S) beam. We have observed that a device with such field configuration is capable of achieving an efficient polarization for a wide range of magnetic field intensities and atomic velocities. In addition, we establish a criterion that must be met to confirm a successful polarization. That is possible due to a specific beating pattern for the Lyman-α radiation expected for the outgoing two-state atomic beam.

High-sensitivity dual-direction weak magnetic field sensor based on structural modulated ultralong period microfiber grating

A high-sensitivity optical fiber dual-direction weak magnetic field sensor based on a structural modulated ultralong period microfiber grating (SULPMG) is proposed. The SULPMG was fabricated by an electric arc discharge and flame-heating drawing method, and the sensor was fabricated by cascading the SULPMG with a core offset section. By tuning the direction of an applied magnetic field, the refractive index of a magnetic fluid (MF) can be tuned accordingly. The transmission spectral response of the proposed sensor was measured and analyzed. For the weak magnetic field intensity range from 0 mT to 7 mT, the obtained magnetic field sensitivity is −1.759 nm/mT and 1.082 nm/mT when the magnetic field is perpendicular or parallel to the light propagation direction, respectively. Theoretical analysis shows that reducing the waist diameter can further improve the sensitivity of the sensor. The proposed sensor is expected to be applied to weak magnetic field measurements in the aviation, vehicle detection and biomedical fields.

Computational Modeling of Optical Fiber-Based Magnetic Field Sensors Using the Faraday and Kerr Magnetooptic Effects

Fiber-optic magnetic field sensors are attracting interest for applications in navigation, magnetic resonance, geophysics, space systems, power transformers, and generators, especially for harsh environments, at long distances, and for multiple monitoring points. This article presents a computational modeling for optical fiber-based magnetic field sensors using the magnetooptical Faraday and Kerr effects on the polar configuration. We propose two sensor profiles: one using a thin film of Fe and the other using a Ce:YIG layer. A simplified analytical model based on Fresnel equations is used to guide the numerical modeling built on COMSOL Multiphysics. The sensors’ design methodology is also presented, which optimizes the sensor operating range and sensitivity. The proposed sensor sensitivity, resolution, and operating range are presented and compared to others found in the literature. The results indicate the possibility of building high-resolution sensors for a restricted range of magnetic field intensities or a wide-operating range sensor.

MHD forced convection flow in dielectric and electro-conductive rectangular annuli

Abstract The Breeding Blanket is a fundamental component of a nuclear fusion reactor and the Water-Cooled Lead Lithium (WCLL) blanket is one of the possible solutions proposed. In this concept, liquid lithium-lead eutectic alloy (PbLi) serves as tritium breeder, tritium carrier and neutron multiplier. The liquid metal is distributed within the breeding zone by two co-axial rectangular channels and, interacting with the reactor magnetic field, leads to the arising of MagnetoHydroDynamic (MHD) effects. In this work, the general-purpose CFD code Ansys CFX 18.2 is used to study this uncommon configuration, modelled as a prototypical square annular channel. The study covers a wide range of magnetic field intensity (up to H a = 2000 ) and two values for the wall conductance ratio ( c w = 0 and c w = 0.1 ) representing, respectively, the ideal insulated case and one more closely approaching the WCLL manifold actual conditions. For both these scenarios, characteristic flow features and their evolution with increasing magnetic field are discussed. A correlation is found linking the pressure loss in the studied configuration and an equivalent square channel through a corrective factor e , which exhibits an asymptotic behavior for H a > 1000 equal to e c w = 0 ≅ 2.44 and e c w = 0.1 ≅ 1.12 .

Barkhausen noise analysis of friction stir processed steel plate

This work investigates the variation in material properties of steel upon friction stir processing through its magneticresponse. The steel plate of grade IS 2062 having a thickness of 3 mm have been friction stir processed (FSPed) using a toolof tungsten carbide with a 15 mm shoulder diameter along with 3 mm pin diameter with traverse of 150 mm/minute and a800 RPM revolving speed. Magnetic response of these processed plate and base metal has been recorded using Barkhausennoise (BN) analyzer in terms of BN signal parameters i.e. the rms value and pulse count or number of pulses. Barkhausennoise analysis results have been validated with micro-hardness testing and metallographic study of as received metal and theprocessed samples. Higher microhardness has been found in processed sample in comparison to the as received metal due tograin refinement owing to the combined effect of plastic flow of material during stirring action of the rotating tool and thefrictional heat. Barkhausen noise analysis has been performed in a wide range of magnetic field intensity (MFI) andexcitation frequencies to study their effect on variation in rms value and the number of pulses.

Magnetodiffusion Effect of the Fe–Sn System in a Magnetic Field at 730°С

An experimental study is performed of the effect constant and pulsed magnetic fields have on the coefficient of diffusion for Sn in α-Fe in the 39.8–557.2 kА m−1 range of magnetic field intensities and 1‒21 Hz range of frequencies at 730°С. It is found that the pulsed magnetic fields have a considerable effect on the coefficient of diffusion for Sn in α-Fe. Resonant behavior of the coefficient of bulk diffusion at pulsed magnetic field intensities of more than 238.8 kА m−1 is observed. Possible mechanisms of the observed effect are discussed.

Experimental study on the dehydration performance of synergistic effect of electric field and magnetic field

Electromagnetic synergistic oil-water separation is a promising technology for deep dehydration with higher efficiency, shorter dehydration period and flexible control of field parameters. In this paper, non-conductive silicone oil without colloid and asphaltene was used as the continuous phase. The effect of magnetization and Lorentz force on the continuous phase can be excluded to explore the mechanism of the electric field and magnetic field synergistic dehydration. Firstly, the particle size of droplets was characterized. The results showed that the dispersed phase was uniformly distributed and the average particle size was 18.24 um. Then the dehydration performance of different types of outfields was compared. The experimental results showed that the dehydration performance of AC electric field combined with magnetic field was better than that of single AC electric field. The dehydration performance of AC electric field and magnetic field was better than that of DC electric field and magnetic field. On this basis, the theory of AC polarization-electromagnetic force was proposed. Finally, the influence of magnetic field intensity on dehydration performance was explored, including dehydration depth and dehydration speed, and the optimal magnetic field intensity range in this experiment was obtained, and its value was [0.269, 0.355] T.

High-accuracy numerical calculations of the bound states of a hydrogen atom in a constant magnetic field with arbitrary strength

We develop a simple and effective method for solving the Schrödinger equation of a hydrogen atom in a constant magnetic field with arbitrary strength. Energies are obtained not only for the ground and low-lying states but also for highly excited states with precision from 12 up to 20 decimal digits. The calculations are performed for an entire range of magnetic field intensity up to 9.4×108 Tesla, the strongest field ever observed. The strong point of the development of the method is the construction of an anharmonic oscillator model for a hydrogen atom in a constant magnetic field via the Kustaanheimo–Stiefel transformation. This model allows the use of purely algebraic calculations and the Feranchuk–Komarov (FK) operator method for effectively solving the Schrödinger equation. The advantages of the basis set in this work are also discussed to extend its application to other problems, such as multi-electron atoms in a constant magnetic field. We also provide a program written by FORTRAN for the solutions mentioned above. Program summaryProgram Title: CHAMFProgram Files doi:http://dx.doi.org/10.17632/s5shscgfcj.1Licensing provisions: BSD 3-clauseProgramming language: FORTRAN77Nature of problem: The Schrödinger equation for a hydrogen atom in a magnetic field is rewritten into that of a four-dimensional anharmonic oscillator by using the Kustaanheimo–Stiefel transformation. The later has a structure more convenient for applying the algebraic method based on annihilation and creation operators. Therefore, the FK operator method [1] can be applied for obtaining high-accuracy numerical solutions which means the obtained energies converge to a given precision (up to twenty decimal digits in this work). The method is developed for an entire range of magnetic field intensity up to 9.4×108 Tesla and for not only ground state but also highly excited states.Solution method: The FK operator method is modified and used for the high-accuracy numerical solutions. This method combines with the algebraic technique which is useful for calculating all the needed matrix elements. Thus, the Schrödinger equation becomes the symmetric generalized eigenvalue problem which can be solved by the subroutine dsygvx.f of the LAPACK library [2]. For the better accuracy with quadruple precision, we modify this subroutine and its dependence with using the real*16 number instead of the real*8. Moreover, a free parameter introduced by the FK operator method can be used for increasing the speed of convergence. The optimal choice of this free parameter is implemented in the program.Additional comments including restrictions and unusual features: Operating system: Linux. RAM: at least 1 GByte per core. The gfortran compiler is recommended for this program. The running time is from a centisecond to a few minutes depending on the required precision. However, for the super-strong magnetic fields (γ≥200), the running time may reach to two hours for the precision of twelve decimal digits, and RAM is needed to be at least 60 GB.[1] I. Feranchuk, A. Ivanov, Van-Hoang Le, A. Ulyanenkov, Non-perturbative Description of Quantum Systems, Springer, Switzerland, 2015. doi:10.1007/978-3-319-13006-4.[2] Netlib.org. LAPACK: Linear Algebra PACKage, Subroutine dsygvx.f. URL http://www.netlib.org/lapack/lapack-3.1.1/html/dsygvx.f.html

Adaptive Damping of a Double‐Beam Structure Based on Magnetorheological Elastomer

A method of vibration reduction based on activation of an MRE block that couples twin cantilever beams at their free ends is investigated. Four types of magnetorheological elastomers have been manufactured, and their rheological properties in a range of magnetic field intensities are established. Free vibrations of several double‐beam structures with controllable damping members made of these MREs are investigated, and a method of semiactive control of such structures is proposed. The effects of compression of the elastomers and alignment of the magnets used to activate them are reported. The mathematical modeling of the system is verified experimentally.