Magnetic Field Research Articles

Magnetically oriented nanosheet interlayer for dynamic regeneration in lithium metal batteries

Lithium (Li) metal has been recognized as a promising anode to advance the energy density of current Li-based batteries. However, the growth of the solid-electrolyte interphase (SEI) layer and dendritic Li microstructure pose significant challenges for the long-term operation of Li metal batteries (LMBs). Herein, we propose the utilization of a suspension electrolyte with dispersed magnetically responsive nanosheets whose orientation can be manipulated by an external magnetic field during cell operation for realizing in situ regeneration in LMBs. The regeneration mechanism arises from the redistribution of the ion flux and the formation of an inorganic-rich SEI for uniform and compact Li deposition. With the magnetic-field-induced regeneration process, we show that a Li||Li symmetric cell stably operates for 350 h at 2 mA cm-2 and 2 mA h cm-2, ~5 times that of the cell with the pristine electrolyte. Furthermore, the cycling stability can be significantly extended in the Li||NMC full cell of 3 mA h cm-2, showing a capacity retention of 67% after 500 cycles at 1C. The dynamic Li metal regeneration demonstrated here could bring useful design considerations for reviving the operating cells for achieving high-energy, long-duration battery systems.

Improvement of superconducting, morphological, and flux pinning ability of YBa2Cu3O7-y matrix with oxygen and Mn2O3 impurity

Abstract In the current work, the influence of oxygen and Mn2O3 impurity levels intervals 0.00≤x≤0.30 on various key properties such as electrical resistivity, superconducting, flux pinning ability, stabilization of ceramic system, and morphological properties of YBa2Cu3O7-y (Y-123) superconductor were examined by electrical resistivity, critical current density, and scanning electron microscopy (SEM), electron dispersive X-ray (EDX) measurements. The EDX test results indicated that all the Y-123 ceramics produced possessed different composition distributions on the sample surface. SEM photomicrographs also confirmed the improvement in the appearance of surface morphology and crystallinity quality of the YBa2Cu3O7-y system. Moreover, the development in the interaction quality between grains, pinning ability and strength quality of 2D coupled vortices was obtained with the oxygen ambient and optimum manganese impurity addition highly dispersing throughout the intra grain and inter-grain boundary couplings due to the increase in the artificial flux pinning nucleation sites in the Y-123 system. Thus, the best sample with the highest Jc value of 98 A/cm2 showed the most resistance to the applied magnetic field and current. Similarly, the same sample exhibited the greatest superconductive offset (98.320 K) and onset (100.504 K) temperatures values based on the development of the Cu-O coordination and stability of the crystal structure. In conclusion, this comprehensive study based on the analysis of oxygen and Mn2O3 impurity addition mechanism through the YBa2Cu3O7-y ceramic matrix may open a new and applicable field for advanced engineering, heavy industry technology and large-scale applications.

Probing the magnetic fields of starspots with transit mapping

Starspots, regions of strong magnetic fields, serve as indicators of stellar activity and the dynamo mechanism at play in the interior of stars. The magnetic fields of main-sequence stars play a crucial role in driving stellar activity. An effective approach to better understanding stellar magnetic fields and activity lies in the detailed characterisation of starspot properties. We propose a new method for estimating the magnetic fields of starspots that employs modelling techniques of planetary transit mapping, which provides estimates of the size, intensity, and location of spots on the stellar photosphere. A starspot's maximum magnetic field was calculated using the linear relationship with the spot flux deficit, $ spot $ (the spot's brightness times its area) and the well-characterised relation for sunspots determined in this work, $B_ spot (G). Applying this relationship to previously mapped spots on the photospheres of 14 FGK and M stars yields spot maximum magnetic fields ranging from 2700 G to 4600 G, with an overall average of $3900 400$ G. We looked for correlations between starspot magnetic fields and stellar properties.\ We did not find any correlation between a spot's mean extreme magnetic field and effective temperature, nor the differential shear. However, a weak anti-correlation is seen between the spots' magnetic field and stellar age as well as between the magnetic field and the rotation period. When compared with previous results of small-scale magnetic field measurements, the B values obtained here are basically constant and near the saturation limit found for rapid rotators. This implies that it is not the intensity of the magnetic field of starspots that decreases with age but rather the filling factor. This result offers a unique window into the magnetic dynamo of stars.

Shock wave propagation in a real gas with or without gravitational field in the presence of magnetic field and monochromatic radiation via group invariance method

PurposeThis article aims to find the similarity solutions for the one-dimensional motion of spherical symmetric shock wave in non-ideal gas influenced by the azimuthal magnetic field and monochromatic radiation in the presence or absence of gravitational field. This paper also aims to study the effects of physical parameters on the strength of shock wave, and on the flow variables in the flow-field region behind the shock front.Design/methodology/approachThe Roche model is used to describe the gravitational field effects due to a massive nucleus at the point of symmetry. To derive the similarity solutions, the Lie group symmetry method has been used. Also, the numerical solutions to the present problem are obtained by using Rung–Kutta method of the fourth order with the use of Mathematica software. The effects of variation in the parameter of non-idealness of the gas, the gravitation parameter, the strength of the ambient magnetic field and the adiabatic index of the gas on the shock wave, and on the flow variables is discussed. A comparative study between with and without gravitational field is also, made.FindingsFor different choices of the arbitrary constants that appeared in the solution of infinitesimal generators, we have obtained seven distinct cases of similarity solutions. In the absence of the gravitational field, the similarity solution exists to the power and exponential law shock paths, but in the presence of gravitational field, the similarity solution exists to the power law shock path case only. In the absence of gravitational field, the shock strength is enhanced in the exponential law shock path case in comparison to the power law shock path case. It is found that the shock wave decays with an increase in the value of the adiabatic exponent, the strength of magnetic field, non-idealness of the gas or gravitational parameter.Research limitations/implicationsThe consideration of medium under the influence of gravitational field due to a heavy nucleus at the center and presence of magnetic field decrease the shock strength. This result may be helpful in designing space vehicle and jet engine.Practical implicationsThe result of the present study may be used in the analysis of data from the measurements by space craft in the solar wind and in neighborhood of the Earth’s magnetosphere.Social implicationsThe obtained results may be used for mankind.Originality/valueThe study of spherical shock wave propagation influenced by monochromatic radiation and azimuthal magnetic field in a non-ideal gas with or without gravitational field has yet to be discussed by any authors by using the Lie group symmetry method. In this article, we have discussed all possible cases of similarity solutions using the Lie group symmetry method, which is not studied by anyone as known to us.

CHANG-ES. XXXIII. A 20 kpc radio bubble in the halo of the star-forming galaxy NGC 4217

Cosmic rays may be dynamically very important in driving large-scale galactic winds. Edge-on galaxies give us an outsider's view of radio haloes, and of their extra-planar cosmic-ray electrons and magnetic fields. We present a new radio continuum imaging study of the nearby edge-on galaxy NGC\,4217. We examine the distribution of extra-planar cosmic rays and magnetic fields. We observed it with both the Jansky Very Large Array (JVLA) in the $S$ band (2--4\,GHz) and the LOw Frequency ARray (LOFAR) at 144\,MHz. We measured vertical intensity profiles and exponential scale heights. We re-imaged both the JVLA and LOFAR data at matched angular resolution in order to measure radio spectral indices between 144\,MHz and 3\,GHz. Confusing point-like sources were subtracted prior to imaging. We then fitted intensity profiles with cosmic-ray electron advection models, using an isothermal wind model that is driven by a combination of pressure from the hot gas and cosmic rays. We discover a large-scale radio halo on the north-western side of the galactic disc. The morphology is reminiscent of a bubble extending up to 20\,kpc from the disc. We find spectral ageing in the bubble, which allowed us to measure the advection speeds of the cosmic-ray electrons, which accelerate from 300 to $600\ $. Assuming energy equipartition between the cosmic rays and the magnetic field, we estimate the bubble may have been inflated by a modest 10\,<!PCT!> of the kinetic energy injected by supernovae over its dynamical timescale of 35\,Myr. While no active galactic nucleus (AGN) has been detected, such activity in the recent past cannot be ruled out. Non-thermal bubbles with sizes of tens of kiloparsecs may be a ubiquitous feature of star-forming galaxies, and if so this would demonstrate the influence of feedback. Determining possible contributions by AGN feedback will require deeper observations.

Correction of dynamic magnetic field errors at the rapid cycling synchrotron of China Spallation Neutron Source

At a Rapid Cycling Synchrotron (RCS), dynamic magnetic field errors, such as magnetic field tracking errors and dynamic fringe field effects, can cause time-dependent tune shift during beam acceleration. If the tune shift is significant enough to pass through resonance lines, it can lead to emittance growth and beam losses. Correcting time-dependent tune shift during acceleration is crucial for a RCS. Modulating the exciting current and magnetic field of quadrupole magnets at a RCS, which are powered by resonant circuits, is challenging during the ramping process. Correcting time-dependent tune shift at a RCS poses a significant technical challenge. We have proposed a method for correcting time-dependent tune shift at the rapid cycling synchrotron of China Spallation Neutron Source (CSNS), based on waveform compensation at the quadrupole magnets. This approach involves modulating the magnetic field variation process by injecting time harmonic exciting current into the quadrupole magnets. This method has been validated during the CSNS beam commissioning and has been applied at the RCS of CSNS to correct various dynamic magnetic field errors.

Study of Magnetic Hydrogel 4D Printability and Smart Self‐Folding Structure

4D printing technology offers the potential to create smart structures that respond to external stimuli. This study focuses on a novel magnetic hydrogel with promising applications in 4D printing, particularly for medical devices such as guidewire robots, drug delivery systems, and vascular stents. Magnetic‐responsive hydrogels suitable for 4D printing are scarce, and their complex rheological properties pose challenges for printing. The study investigates these properties and optimizes them through adjustments in ink composition and the application of an external magnetic field, improving printability. Using the direct writing (DLP) method, which allows magnetic programming of individual strands, the study achieves greater flexibility compared to the traditional SLA method. Optimized printing parameters and material ratios produced high‐quality single strands, grids, and sheet‐like structures, demonstrating responsiveness to varying magnetic fields. Results confirm that DLP can be effectively applied to hydrogel 4D printing, achieving flexible structures with tunable mechanical properties. Additionally, magnetic‐responsive, self‐folding hydrogel structures were created, with a response speed of 180 ms under a magnetic field. This research establishes a foundation for magnetic hydrogel 4D printing and offers insights for the development of future smart medical devices.

Revealing the pinning landscape and related vortex pattern evolution in granular superconducting films

Most superconducting electronics based on films exhibit granular structures. It has been suggested that grain boundaries form a network with relatively weak superconductivity, potentially acting as pinning centers. Yet, so far, detailed microscopic studies of the pinning landscape and its relation to vortex behavior remain scarce. Here, we imaged the vortex lattices (VL) in granular Nb films using magnetic force microscopy over large scanning areas at various magnetic fields. A non-monotonic evolution in the degree of vortex lattice ordering was observed with increasing vortex density, driven by a combination of vortex-vortex interactions and pinning effects. The spatial distribution of pinning potential within the film was directly mapped using a recently developed scanning quantum vortex microscope (SQVM). Instead of the network formed by grain boundaries, the pinning landscape presents a network-like structure, yet with domains significantly larger than the individual grains. The results of numerical simulations based on pinning landscape revealed by SQVM well reproduce our experiments. The pinning force per unit length at low magnetic fields was calculated. The critical current density, estimated from the relative positions of vortices, aligns well with the critical state model. Our work illustrates the relationship between the evolution of the vortex lattice with magnetic field and the structural features of granular Nb film, providing new insights into the design of high-performance superconducting electronic devices.

Shift of plasmon resonance in silver nanoparticles: effect of magnetic field pre-treatment

Abstract A novel magnetic field induced phenomenon in ZnO/Ag nanoparticles is detected and investigated with reference to the surface plasmon resonance (SPR) effect. A shift of the maximum of plasmon absorption of the ZnO/Ag nanoparticles formed in different days in magnetic field treated ZnO/ethanol solutions was observed. The observed phenomena were explained in terms of the ferromagnetic-like properties of the ZnO nanoparticles due to the surface broken bonds, which result in the appearance of non-zero magnetic moments. Magnetic field pre-treatment may be used as an effective tool for manipulating the plasmon properties of silver-based nanoparticles, which is perspective for creating new-generation sensor systems.

The putative center in NGC 1052

Context: Many active galaxies harbor powerful relativistic jets, however, the detailed mechanisms of their formation and acceleration remain poorly understood. Aims: To investigate the area of jet acceleration and collimation with the highest available angular resolution, we study the innermost region of the bipolar jet in the nearby low-ionization nuclear emission-line region (LINER) galaxy NGC\,1052. Methods: We combined observations of NGC\,1052 taken with VLBA, GMVA, and EHT over one week in the spring of 2017. Our study is focused on the size and continuum spectrum of the innermost region containing the central engine and the footpoints of both jets. We employed a synchrotron-self absorption model to fit the continuum radio spectrum and we combined the size measurements from close to the central engine out to $ to study the jet collimation. Results: For the first time, NGC\,1052 was detected with the EHT, providing a size of the central region in-between both jet bases of $43\ perpendicular to the jet axes, corresponding to just around $250\,R_ S $ (Schwarzschild radii). This size estimate supports previous studies of the jets expansion profile which suggest two breaks of the profile at around $3 10^3\,R_ S $ and $1 10^4\,R_ S $ distances to the core. Furthermore, we estimated the magnetic field to be 1.25\,Gauss at a distance of $22\ from the central engine by fitting a synchrotron-self absorption spectrum to the innermost emission feature, which shows a spectral turn-over at $ 130\,$GHz. Assuming a purely poloidal magnetic field, this implies an upper limit on the magnetic field strength at the event horizon of $2.6 10^4\,$Gauss, which is consistent with previous measurements. Conclusions: The complex, low-brightness, double-sided jet structure in NGC\,1052 makes it a challenge to detect the source at millimeter (mm) wavelengths. However, our first EHT observations have demonstrated that detection is possible up to at least 230\,GHz. This study offers a glimpse through the dense surrounding torus and into the innermost central region, where the jets are formed. This has enabled us to finally resolve this region and provide improved constraints on its expansion and magnetic field strength.

Investigation of comparative entropy in different nanofluids inspired by solar radiations and unsteady effects: Model analysis for permeable channel

Entropy analysis in nano as well as conventional fluids is of paramount interest and highly affected by the active physical quantities. The research provides comprehensive comparative entropy performance of multiple nanofluids in the view of model quantities. The physical model considered in the presence of solar radiations, dissipation energy and magnetic field. The multiple fluids squeezed in a channel formed by two horizontal sheets with upper non-stationary surface. The entropy modeling performed using similarity variables for transient flow and governing laws. The numerical approach (RK method coupled with shooting scheme) is used for entropy results which obtained for ternary, hybrid, nano and base fluids. It is found that entropy optimized in ternary nanofluid while hybrid, nano and common fluids caused reduction in it. Dissipation effects (Ec=0.1,0.3,0.5,0.7) increases the entropy while significant reduction is observed for Ω1=0.1,0.2,0.3,0.4. The solar radiations in the range of Rd=1.0 to Rd=7.0 contributes effectively to improve entropy phenomena in both inward and outward plate movement. Thus, the system can be maintained at low entropy by strengthening the effects of Ω1 and optimum entropy is subject to Eckert number, α=0.1,0.2,0.3,0.4, radiations (Rd=1.0,3.0,5.0,7.0) for S>0.0 and S<0.0, respectively.

Performance evaluation of a racetrack high temperature superconductor winding in an HTS levitation platform

Abstract High temperature superconducting (HTS) is a key technology of next generation high-speed railway systems, which guarantees high current and highly efficient traction power supply. HTS devices can reduce system weight and thus improve loads of vehicles. On high-speed maglev trains, HTS windings wound by second-generation (2G) HTS tapes play an important role in suspension and traction. However, in complex ferromagnetic environments, the performances of windings are notably influenced by the varying magnetic fields. In this paper, a new maglev platform is designed and comprised of a winding of six racetrack HTS coils, an E shape iron core and a magnetic guide rail. The air core structure of the winding is modeled，tested and the electromagnetic characteristics are analyzed for three dimensional (3D) finite element analysis of the platform. An A formulation is used to calculate magnetic vectors A and infer magnetic flux densities and current densities for the structures. After the winding is installed on the iron core and the magnetic guide rail is suspended above the iron core, the air gap between the iron core and the rail is varied from 0 mm to 20 mm in models and experiments. The magnetic fields, critical currents and losses of the winding in cases of the air core and the iron core conditions are used for analysis. The comparison between the air core and the iron core conditions confirms the reliability of the proposed models. This study provides means for analysis of complex superconducting maglev systems.

Magnetic Induction Tomography for Brain Tissue Imaging Based on Conductivity Distribution for Parkinson’s Disease Diagnosis

Parkinson's disease is a prevalent neurodegenerative complication defined by the accumulation of alpha synuclein lewy bodies in the brain. Misdiagnosis results widespread of Parkinson’s disease because clinical diagnosis is challenging, underlining a need of a better detection technique, such as non-invasive magnetic induction tomography (MIT) technique. Non-invasive techniques for biological tissues imaging are becoming popular in biomedical engineering field. Therefore, MIT technology as a non-invasive technique has been encouraged in a medical field due to its advancement of technology in diagnosing diseases. The measurement parameters in MIT are passive electromagnetic properties (conductivity, permittivity, permeability) for biological tissue and the most dominant parameter in MIT is conductivity properties. It is uses a phase shift between a primary magnetic field and an induced field caused by a target object's conductivity. As a function of conductivity, the phase shift between the applied and secondary fields is expressed. Thus, the phase shift can be used to characterize the conductivity of a target object. The phase shift between the excitation and induced magnetic fields (EMF and IMF) reflects the change in conductivity in biological tissues. This paper focuses on the virtual simulation by using COMSOL Multi-physics for the design and development of MIT system that emphasizes on single channel magnetic induction tomography for biological tissue (bran tissue) imaging based on conductivity distribution for Parkinson’s disease diagnosis. The develop system employs the use of excitation coils to induce an electromagnetic field (e.m.f) in the brain tissue, which is then measured at the receiving side by sensors. The proposed system is capable of indicating Parkinson’s disease based on conductivity distribution. This method provides the valuable information of the brain abnormality based on differences of conductivities of normal brain and Parkinson’s disease brain tissues.

Computational Analysis of Unsteady Oscillatory Flow of Nanofluid with Variable Electric Conductivity: Gear-Generalized Differential Quadrature Approach

Abstract The present study numerically investigated the entropy production in nanofluids' dissipative unsteady oscillatory flow characterised by variable electric conductivity and magnetic heating effects. The imposition of the non-isothermal boundary condition on the oscillatory stretching sheet plays a crucial role in establishing the self-similar solution in the presence of viscous heating. An external magnetic field (uniform in space and time) is imposed perpendicular to the plane of the oscillating stretched boundary. The energy equation, incorporating viscous dissipation effects and momentum equation, is reduced to nonlinear coupled partial differential equations and numerically solved using the Gear-generalized differential quadrature scheme. The Corcione model is implemented to describe the nanofluid's effective viscosity and thermal conductivity. Furthermore, expressions for entropy production and relative irreversibility parameter (Bejan number), considering variable electric conductivity, are derived and computed based on solutions obtained from momentum and energy equations. The impacts of parameters such as magnetic parameter, variable electric conductivity parameter, Eckert number, Strouhal number, Prandtl number and temperature difference parameters on flow, heat transfer, entropy generation, and Bejan number are systematically illustrated and examined. We observed that increasing the variable electric conductivity parameters reduces the velocity profiles while improving the thermal fields. Similar behaviour is found when the strength of a magnetic field is increased. The skin friction coefficient exhibits an augmentation in response to the Eckert number, dimensionless time, Strouhal number, nanoparticle volume fraction, magnetic parameter, and variable thermal conductivity parameter. Conversely, the Nusselt number increases concerning the Strouhal number and nanoparticle volume fraction. At the same time, it declines in association with the magnetic parameter, dimensionless time, Eckert number, and variable electric conductivity parameter. Additionally, to ensure the precision and reliability of the outcomes, the numerical code undergoes a thorough validation process that involves comparing its outputs to the findings of previous available studies. This comprehensive investigation enhances our understanding of nanofluid dynamics and provides valuable insights for optimising thermal management systems across various engineering disciplines.

Design of a compact beam transport system for laser-driven proton therapy

Abstract We put forward a new design of a compact beam transport system for intense laser-driven proton therapy, where instead of using conventional pulsed solenoids, our design relies on a helical coil irradiated by a nanosecond laser pulse to generate strong magnetic fields for focusing protons. A pair of dipole magnets and apertures are employed to further filter protons with large divergences and low energies. Our numerical studies combine particle-in-cell simulations for laser-plasma interaction to generate high-energy monoenergetic proton beams, finite element analysis for evaluating the magnetic field distribution inside the coil, and Monte-Carlo simulations for beam transport and energy deposition. Our results show that with this design, a spread-out Bragg peak in a range of several centimeters to a deep-seated tumor with a dose of approximately 16.5 cGy and fluctuation around 2% can be achieved. The instantaneous dose rate reaches up to 109 Gy/s, holding the potential for future FLASH radiotherapy research.

Synchrotron CT dosimetry for wiggler operation at reduced magnetic field and spatial modulation with bow tie filters.

The Australian Synchrotron Imaging and Medical Beamline (IMBL) uses a superconducting multipole wiggler (SCMPW) source, dual crystal Laue monochromator and 135 m propagation distance to enable imaging and computed tomography (CT) studies of large samples with mono-energetic radiation. This study aimed to quantify two methods for CT dose reduction: wiggler source operation at reduced magnetic field strength, and beam modulation with spatial filters placed upstream from the sample. Transmission measurements with copper were used to indirectly quantify the influence of third harmonic radiation. Operation at lower wiggler magnetic field strength reduces dose rates by an order of magnitude, and suppresses the influence of harmonic radiation, which is of significance near 30 keV. Beam shaping filters modulate the incident beam profile for near constant transmitted signal, and offer protection to radio-sensitive surface organs: the eye lens, thyroid and female breast. Their effect is to reduce the peripheral dose and the dose to the scanned volume by about 10% for biological samples of 35-50 mm diameter and by 20-30% for samples of up to 160 mm diameter. CT dosimetry results are presented as in-air measurements that are specific to the IMBL, and as ratios to in-air measurements that may be applied to other beamlines. As CT dose calculators for small animals are yet to be developed, results presented here and in a previous study may be used to estimate absorbed dose to organs near the surface and the isocentre.

Time-resolved x-ray imaging of nanoscale spin-wave dynamics at multi-GHz frequencies using low-alpha synchrotron operation

Time-resolved x-ray microscopy is used in a low-alpha synchrotron operation mode to image spin dynamics at an unprecedented combination of temporal and spatial resolution. Thereby, nanoscale spin waves with wavelengths down to 70 nm and frequencies up to 30 GHz are directly observed in ferromagnetic thin film microelements with spin vortex ground states. In an antiparallel ferromagnetic bilayer system, we detect the propagation of both optic and acoustic modes, the latter exhibiting even a strong non-reciprocity. In single-layer systems, quasi-uniform spin waves are observed together with modes of higher order (up to the 4th order), bearing precessional nodes over the thickness of the film. Furthermore, the effects of magnetic material properties, film thickness, and magnetic fields on the spin-wave spectrum are determined experimentally. Our experimental results are consistent with numerical calculations from a micromagnetic theory even on these so-far unexplored time- and length scales.

Doping effects in strontium hexaferrite: Theoretical and experimental analysis

Hexagonal ferrites based on SrFe12O19 (SFO) are vital materials in the field of permanent magnets, valued for their cost-effectiveness and reliable magnetic properties, making them a more affordable alternative to rare-earth permanent magnets. This study focuses on understanding the doping effects of commonly used elements in SFO system. DFT calculation results show that doping La or La-Co can enhance the phase stability of SFO, in which Co has a preference for the 4f1 sites of Fe. The total magnetic moment was observed to slightly decrease with La doping, whereas it exhibited an increasing trend with La-Co and La-Ca-Co co-doping and the largest increase of 6.5 % can be obtained in Sr2LaCaFe44Co4O76 (SLCFCO). The increase in the total magnetic moment is mainly attributed to the smaller antiferromagnetic moment of Co than that of Fe on 4f1 sites, as well as the reduction in the antiferromagnetic Fe moments at 4f1 and 4f2 sites. The total density of states indicates a transition from semiconductor behavior to a metallic character both in the La-Co and La-Ca-Co doped versions. The experimental results validate the theoretical predictions, confirming enhancements in magnetic performance. The saturation magnetization increased from 63.86 Am2/kg in SrFe11.7O19 (SFO) to 67.53 Am2/kg in Sr0.4La0.4Ca0.2Fe10.5Co0.5O19 composition. These findings provide a vital understanding of tuning the magnetic and electronic properties in doped SFO, which will enable the development of advanced applications in magnetic materials.

Design, development and test of single beamlet microwave ion source with spot-dense plasma system

In this paper, an efficient ion source with unique characteristics is introduced and proposed. It outlines the generation of a spot-dense plasma just below the plasma electrode aperture of the extractor system through the utilization of a 2.45 GHz microwave plasma source with a power of 1000 W, in the absence of a magnetic field. This source utilizes a 2.45 GHz microwave plasma generator operating at 1000 W, resulting in the generation of a spot-dense plasma just below the plasma electrode aperture of the extractor system, all achieved without the need for a magnetic field.The spot-dense plasma results in the extraction of an ion beam with high current density. Furthermore, the suggested ion source can be utilized in a smaller size using a higher frequency. Therefore, our findings indicate that the proposed method not only substantially enhances the extracted positive ion beam current but also significantly reduces the size of the ion beam source system. Based on the design and simulation results, an experimental model of the ion beam source is constructed. The diagnostic tools provided the beam current density and system efficiency values of 99mA/cm2 and 7×10−6A/W, respectively.

Development of differential hall sensors for Pulsed Eddy Current Testing using Gaussian pulse excitation

This study presents the use of differential Hall sensors in Pulsed Eddy Current Testing with Gaussian pulse excitation. This method was selected for its ability to effectively distribute energy across the frequency spectrum, thereby enhancing inspection depth and precision compared to the conventional rectangular pulses. The design of the differential Hall sensors, which includes two Hall sensors, greatly minimizes interference from the primary magnetic field, resulting in improved accuracy in detecting defects, particularly corrosion, across varying lift-off distances. 3D-FEM simulations and experimental results demonstrate that differential Hall sensors outperform traditional single Hall sensors in reducing noise and maintaining corrosion signal. Compared to traditional single Hall sensors, the differential Hall sensors exhibit a significantly improved signal-to-noise ratio, particularly at larger lift-off distances. Additionally, the study employs the Full Width at Half Maximum method to accurately estimate the size of corrosion, offering a precise and non-invasive approach to assessing structural integrity.