Field Strength Research Articles

Commissioning and operation of 11.74T human MRI magnet for Gachon university gil medical center, South Korea

Abstract Magnetic resonance imaging (MRI) systems with magnetic field strengths higher than 7 Tesla (T), offer exceptional image resolution and signal-to-noise ratio, enabling more detailed visualization of fine anatomical structures, especially for brain, musculoskeletal, and cardiovascular studies. Only a few of them are operating in the whole world. An 11.74 T magnet for human MRI has been commissioned at Gachon University Gil Medical Center (GUGMC) in South Korea in 2022 and has now exceeded two-year operational life at full field. An overview of its features, the commissioning test campaign, and the experience gained after operations is presented.

Impact of electric field on donor energy and polarisability in GaAs variant toroidal quantum ring

ABSTRACT This study investigates the electronic properties of a GaAs Variant Toroidal Quantum Ring (VTQR) containing an off-centre donor impurity, focussing on the effect of an external electric field on donor energy and polarisability. Based on the effective mass approximation, we solved the Schrödinger equation using the finite difference method. The results show a typical effect at a toroidal angle of 180 ∘ , where the strength of the electric field leads to a decrease in the donor energy. Intriguingly, at toroidal angles of 90 ∘ and 60 ∘ , the donor energy increases with increasing field strength, indicating improved electron confinement. The probability density distributions shown reveal the location of the electron as influenced by the applied field. Furthermore, polarisability reaches its maximum around an angle of about 80 ∘ for all electric field strengths. This work provides a better understanding of the behaviour of electron in quantum ring systems and suggests potential for the engineering of tunable quantum devices.

Gate leakage mechanisms in Al2O3/SiN/AlN/GaN MIS-HEMTs on Si substrates

Abstract This study investigates the gate leakage mechanisms of AlN/GaN metal-insulator-semiconductor highelectron-mobility transistors (MIS-HEMTs) fabricated on silicon substrate with Al2O3/SiN as stacked gate dielectrics, analyzing behaviors across high and low temperature conditions. In the high-temperature reverse bias region (T > 275 K, V G < 0 V), Poole-Frenkel emission (PFE) dominates at low electric fields, while trap-assisted tunneling (TAT) is the primary mechanism at medium to high electric fields. The shift from PFE to TAT as the dominant conduction mechanism is due to the increased tunneling effect of electrons as the electric field strength rises. Additionally, TAT is found to be the main gate leakage mechanism under low-temperature reverse bias (T < 275 K, V G < 0 V). At lower temperatures, the reduction in electron energy causes the emission process to rely more on electric field forces. Furthermore, under forward bias conditions at both high and low temperatures(225 K < T < 375 K, V G > 0 V), conduction is primarily dominated by defect-assisted tunneling (DAT).

Observationally derived magnetic field strength and 3D components in the HD 142527 disk

Observationally derived magnetic field strength and 3D components in the HD 142527 disk

Magnetic Field Strengths in the Vicinity of Sgr A* via 18 cm Zeeman Observations

Abstract Very Large Array (VLA) observations of 18 cm OH absorption lines were used to determine the strength of the line-of-sight magnetic field in the Galactic center region. This study is an extension of the VLA OH Zeeman observations of Killeen et al. with fourfold the on-source integration time and twice the sensitivity to the Zeeman effect. The new data fail to confirm the 7σ Zeeman detections of 2 mG fields reported in the earlier work. Also, we cannot reproduce these reported detections from our own analysis of archival data of the earlier work. We find no certain detections of the OH Zeeman effect in the Galactic center region. Our results suggest magnetic fields of no more than about a milligauss in the sampled regions.

Pulsed vector atomic magnetometer using an alternating fast-rotating field

We introduce a vector atomic magnetometer that employs a fast-rotating magnetic field applied to a pulsed 87Rb scalar atomic magnetometer. This approach enables simultaneous measurements of the total magnetic field and its two polar angles relative to the rotation plane. Operating in gradiometer mode, the magnetometer achieves a total field gradient sensitivity of 35 fT/Hz (0.7 parts per billion) and angular resolutions of 6 nrad/Hz at a 50 μT Earth field strength. The noise spectra remain flat down to 1 Hz and 0.1 Hz, respectively. Here we show that this method overcomes several metrological challenges commonly faced by vector magnetometers and gradiometers. We propose a unique peak-altering modulation technique to mitigate systematic effects, including a newly identified dynamic heading error. Additionally, we establish the fundamental sensitivity limits of the sensor, demonstrating that its vector sensitivity approaches scalar sensitivity while preserving the inherent accuracy and calibration benefits of scalar sensors. This high-dynamic-range, ultrahigh-resolution magnetometer offers exceptional versatility for diverse applications.

Simulation of electron and nuclear spin dynamics in many-spin charge-separated states.

This study presents a numerical simulation approach to investigate singlet-triplet interconversion effects in organic materials with rigid molecular structures that facilitate the photogeneration of charge-separated (CS) states, such as zwitterions resulting from intramolecular electron transfer. Our approach enables the detailed modeling of electron and nuclear spin-dependent observables, including magnetic field-affected reaction yields (MARY) and chemically induced dynamic nuclear polarization (CIDNP). The equilibrium solution of the stochastic Liouville equation can be obtained with simple algebraic manipulation by noting the relationship between the Laplace transform of the density operator and the time-domain representation of the same operator. Experimental MARY and CIDNP data are modeled as functions of key external and internal system parameters, such as magnetic field strength, hyperfine interactions, and exchange couplings. This allows for exploring processes that are otherwise experimentally inaccessible, providing deeper insights into the spin dynamics of the photoinduced CS state. Understanding these interconversion processes is not only essential for the fundamental photochemistry studies but also for the rational design and development of novel organic materials for photovoltaics and photocatalysis. Our results demonstrate the significant impact of singlet-triplet interconversion on the overall efficiency of charge separation and recombination processes, highlighting the importance of spin dynamics in the design of next-generation organic photovoltaic materials.

Low-temperature growth of wafer-scale amorphous boron nitride films with low-dielectric-constant and controllable thicknesses.

Amorphous boron nitride (aBN) films, with extremely low relative dielectric constant (κ) and chemical inertness, are excellent insulation and packaging materials for electronic device interconnection. It is of great significance to prepare the low-κ aBN films with controllable thickness, but there are still some limitations to achieve the goal. In this study, we succeed in growing wafer-scale aBN films with specific thicknesses from 1.2 to 4.0 nm by varying the growth time and temperature. The thickness of the films increases linearly with growth time and the crystallinity of BN films is precisely controlled by the growth temperature. The preferred temperature for aBN films ranges from 200 to 400 °C. Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscope all confirm the amorphous feature. These films are wafer-scale uniformity and have an ultra-flat surface, with excellent thermal stability and corrosion resistance. Particularly, the growth temperature affects the κ value and breakdown voltage of aBN films. The aBN films grown at 200 °C have the lowest κ value of 1.66 at 100 kHz, along with the breakdown field strength of 5.5 MV/cm. We believe that wafer-level aBN films with various thicknesses can bring new opportunities for the development and application of nanoscale electrical devices.

Magnetic Fields in Massive Star-forming Regions (MagMaR): The Magnetic Field at the Onset of High-mass Star Formation

Abstract A complete understanding of the initial conditions of high-mass star formation and what processes determine multiplicity requires the study of the magnetic field in young massive cores. Using Atacama Large Millimeter/submillimeter Array (ALMA) 250 GHz polarization observations (0 . ″ 3 = 1000 au) and ALMA 220 GHz high-angular-resolution observations (0 . ″ 05 = 160 au), we have performed a full energy analysis including the magnetic field at core scales and have assessed what influences the multiplicity inside a massive core previously believed to be in the prestellar phase. With a mass of 31 M ⊙, the G11.92 MM2 core has a young CS molecular outflow with a dynamical timescale of a few thousand years. At high resolution, the MM2 core fragments into a binary system, with a projected separation of 505 au and a binary mass ratio of 1.14. Using the Davis–Chandrasekhar–Fermi method with an angle dispersion function analysis, we estimate in this core a magnetic field strength of 6.2 mG and a mass-to-magnetic-flux ratio of 18. The MM2 core is strongly subvirialized, with a virial parameter of 0.064, including the magnetic field. The high mass-to-magnetic-flux ratio and low virial parameter indicate that this massive core is very likely undergoing runaway collapse, which is in direct contradiction with the core accretion model. The MM2 core is embedded in a filament that has a velocity gradient consistent with infall. In line with clump-fed scenarios, the core can grow in mass at a rate of 1.9–5.6 × 10−4 M ⊙ yr−1. In spite of the magnetic field having only a minor contribution to the total energy budget at core scales (a few thousands of astronomical units), it likely plays a more important role at smaller scales (a few hundreds of astronomical units) by setting the binary properties. Considering energy ratios and a fragmentation criterion at the core scale, the binary system could have been formed by core fragmentation. The binary system properties (projected separation and mass ratio), however, are also consistent with radiation-magnetohydrodynamic simulations with super-Alfvenic or supersonic (or sonic) turbulence that form binaries by disk fragmentation.

Influence of field strength on quantitative parameters and feature stability in the assessment of the ovaries using 1.5-T and 3-T MRI.

Little is known of the influence of scanner field strength on quantitative diffusivity variables, especially kurtosis in healthy ovaries. To evaluate the influence of scanner field strength on quantitative diffusion variables in pelvic MRI of the ovaries. This prospective, single-centre study consisted of repeated 1.5-T and 3-T examinations in 30 female volunteers (mean age=27.9 years, age range=20.3-45.2 years) from July 2017 to September 2019. Multi b-value DWI 0, 50, 100, 800, 1500, 2000 s/mm2 was acquired over three timepoints during the menstrual cycle. Ovaries were segmented at b = 1500 s/mm2. Median apparent diffusion coefficient (ADC) and advanced kurtosis parameters Dapp and Kapp were calculated. Statistical analysis was performed with the variations of diffusivity variables being compared between 1.5-T and 3-T MRI using a Mann-Whitney rank-sum test. Median ADC and Dapp (µm²/ms) did not statistically differ. Median ADC were 1.509 (range=1.371-1.610), 1.619 (range=1.463-1.747), and 1.511 (range=1.423-1.639) at 1.5 T; 1.542 (range=1.428-1.682), 1.658 (range=1.510-1.806), and 1.572 (range=1.455-1.709) at 3 T (P = 0.14, 0.19, and 0.07), whereas median Dapp were 2.024 (range=1.913-2.152), 2.192 (range=2.010-2.327), and 2.045 (range=1.958-2.170) at 1.5 T; 2.013 (range=1.952-2.188), 2.179 (range=2.018-2.327), and 2.082 (range=1.959-2.194) at 3 T (P = 0.77, 0.99, and 0.34) for timepoints 1, 2, and 3, respectively. Statistical comparison of Kapp revealed significant differences for all timepoints: 0.629 (range=0.595-0.652), 0.604 (range=0.574-0.651), and 0.622 (range=0.581-0.664) at 1.5 T; 0.601 (range=0.563-0.626), 0.567 (range=0.526-0.633), and 0.599 (range=0.541-0.650) at 3 T (P < 0.001, 0.005, and 0.03). Diffusivity mapping in the ovaries provides similar absolute median diffusion values, but statistically significant differences in absolute kurtosis values between 1.5 T and 3 T.

Primary scalar hair in Gauss–Bonnet black holes with Thurston horizons

Abstract In this work, we construct novel asymptotically locally AdS $$_5$$ 5 black hole solutions of Einstein–Gauss–Bonnet theory at the Chern–Simons point, supported by a scalar field that generates a primary hair. The strength of the scalar field is governed by an independent integration constant; when this constant vanishes, the spacetime reduces to a black hole geometry devoid of hair. The existence of these solutions is intrinsically tied to the horizon metric, which is modeled by three non-trivial Thurston geometries: Nil, Solv, and $$SL(2,{\mathbb {R}}).$$ S L ( 2 , R ) . The quadratic part of the scalar field action corresponds to a conformally coupled scalar in five dimensions -an invariance of the matter sector that is explicitly broken by the introduction of a quartic self-interaction. These black holes are characterized by two distinct parameters: the horizon radius and the temperature. Notably, there exists a straight line in this parameter space along which the horizon geometry exhibits enhanced isometries, corresponding to solutions previously reported in JHEP 02, 014 (2014). Away from this line, for a fixed horizon radius and temperatures above or below a critical value, the metric’s isometries undergo spontaneous breaking. Employing the Regge–Teitelboim approach, we compute the mass and entropy of these solutions, both of which vanish. Despite this, only one of the integration constants can be interpreted as hair, as the other modifies the local geometry at the conformal boundary. Finally, for Solv horizon geometries, we extend these hairy solutions to six dimensions.

Nonlinear vibrations of graphene nanoplates with arbitrarily orientated crack located in magnetic field using nonlocal elasticity theory

PurposeThe study explores frequency curves and natural frequencies as functions of crack length, crack angle, magnetic field strength and small size effects under the three boundary conditions.Design/methodology/approachThis study investigates the nonlinear dynamics of a single-layered graphene nanoplate with an arbitrarily oriented crack under the influence of a magnetic field. The research focuses on three boundary conditions: simply supported, clamped and clamped-simply supported. The crack effect is modeled by incorporating membrane forces and additional flexural moments created by the crack into the equation of motion.FindingsResults reveal that increasing the crack length, small size effects and magnetic field intensity reduces the flexural stiffness of the nanoplate, increases the compressive load and lowers its natural frequency. Additionally, excessive magnetic field intensity may lead to static buckling. The critical dimensionless magnetic fields are found to be 33.6, 95.1 and 72.3 for All edges of the nanoplate are simply supported (SSSS), fully clamped edges (CCCC) and two opposite edges are clamped and the other are simply supported (CSCS) nanoplates, respectively. Furthermore, for SSSS and CCCC boundary conditions, an increase in the crack angle results in a softening behavior of the hard spring. In contrast, the SCSC boundary condition exhibits the opposite behavior. These findings emphasize the importance of considering the effects of angled cracks and electromagnetic loads in the analysis and design of graphene-based nanostructures.Originality/valueNovel equations are derived to account for the applied loads induced by the magnetic field. The nonlinear equation of motion is discretized using the Galerkin technique, and its analytical response is obtained via the multiple time-scales perturbation technique.

Electro-Elastic Instability and Turbulence in Electro-osmotic Flows of Viscoelastic Fluids: Current Status and Future Directions

The addition of even minute amounts of solid polymers, measured in parts per million (ppm), into a simple Newtonian fluid like water significantly alters the flow behavior of the resulting polymer solutions due to the introduction of fluid viscoelasticity. This viscoelastic behavior, which arises due to the stretching and relaxation phenomena of polymer molecules, leads to complex flow dynamics that are starkly different from those seen in simple Newtonian fluids under the same conditions. In addition to polymer solutions, many other fluids, routinely used in various industries and our daily lives, exhibit viscoelastic properties, including emulsions; foams; suspensions; biological fluids such as blood, saliva, and cerebrospinal fluid; and suspensions of biomolecules like DNA and proteins. In various microfluidic platforms, these viscoelastic fluids are often transported using electro-osmotic flows (EOFs), where an electric field is applied to control fluid movement. This method provides more precise and accurate flow control compared to pressure-driven techniques. However, several experimental and numerical studies have shown that when either the applied electric field strength or the fluid elasticity exceeds a critical threshold, the flow in these viscoelastic fluids becomes unstable and asymmetric due to the development of electro-elastic instability (EEI). These instabilities are driven by the normal elastic stresses in viscoelastic fluids and are not observed in Newtonian fluids under the same conditions, where the flow remains steady and symmetric. As the electric field strength or fluid elasticity is further increased, these instabilities can transition into a more chaotic and turbulent-like flow state, referred to as electro-elastic turbulence (EET). This article comprehensively reviews the existing literature on these EEI and EET phenomena, summarizing key findings from both experimental and numerical studies. Additionally, this article presents a detailed discussion of future research directions, emphasizing the need for further investigations to fully understand and harness the potential of EEI and EET in various practical applications, particularly in microscale flow systems where better flow control and increased transport rates are essential.

Unsteady Magneto-radiative Flow of Copper-water Nanofluid Over an Exponentially Stretching Surface

Understanding the complex behavior of fluid flows under various physical influences is crucial for advancing engineering and industrial applications. This paper presents the investigation of the unsteady, incompressible, single-phase magneto-radiative flow of a copper-water nanofluid over an exponentially stretching surface, considering the effects of viscous dissipation and temperature-dependent heat sources. This model, proposed in the present analysis, is based on fundamentals of the continuity and Navier–Stokesequations with mass conservation. Further, use of a similarity transformation will reduce the equations to dimensionless form and provide a numerical solution using the Runge–Kutta–Fehlberg method. In physics, engineering, and industrial applications, the most interesting parameters are the velocity, temperature, skin friction, and the Nusselt number (Nu). The results of this study are compared with previous works, showing significant agreement with findings under similar conditions. The analysis reveals that both temperature and velocity boundary layer increase when all very specific effects of radiation (R), heat source (Q), copper nanoparticle volume fraction, and magnetic field strength parameter are present. On the other hand, it is found that skin friction increases when considering both copper nanoparticle volume fraction and magnetic field strength parameter, but the Nu decreases if R, Q, copper nanoparticle volume fraction, and magnetic field strength parameter are the factors responsible for that. These outcomes will be further delineated through graphics and be elaborated in engineering and industrial context.

Assessment of Airfoil Lightning Strikes Characterization on Aircraft in Dynamic Conditions

Lightning is a long-gap high-current discharge event in nature, and its enormous discharge energy can cause structural damage to struck objects. Relevant studies have shown that aircraft in the air are exposed to a higher risk of lightning strikes than ground objects. However, most studies on aircraft lightning strikes have used static models, and there are still shortages of research objects under high-speed movements. Therefore, it is necessary to conduct an investigation of the lightning strike characteristics of aircraft under dynamic conditions to ensure flight safety fully. In this study, the lightning strike characteristics of airfoil under dynamic conditions have been simulated by studying two variables, airspeed and angle of attack, while employing the Leader Progression Model (LPM). The results show that adjustments in the angle of attack cause changes in the atmospheric pressure field, and a maximum pressure difference of up to 5.44 × 104 Pa is observed at the angle of attack of 15°, which results in a change in the average electric field strength Estr, leading to a 33.63% difference in the upward leader trigger height. At an airspeed equal to 120 m/s, the trigger height in the low-pressure region is only 54.7% of that in the high-pressure region (435 m and 795 m, respectively). A higher lightning strike risk is found in areas of higher air pressure and is positively correlated with angle of attack and airspeed.

Multi-observatory Study of Young Stellar Energetic Flares (MORYSEF): No Evidence for Abnormally Strong Stellar Magnetic Fields after Powerful X-Ray Flares

Abstract We explore the empirical power-law relationship between X-ray luminosity (L X) and total surface magnetic flux (Φ), established across solar magnetic elements, time- and disk-averaged emission from the Sun, older active stars, and pre-main-sequence (PMS) stars. Previous models of large PMS X-ray flares, lacking direct magnetic field measurements, showed discrepancies from this baseline law, which MHD simulations attribute to unusually strong magnetic fields during flares. To test this, we used nearly simultaneous Chandra X-ray and HET-HPF near-infrared observations of four young Orion stars, measuring surface magnetic fields during or just after powerful PMS X-ray flares. We also modeled these PMS X-ray flares, incorporating their measured magnetic field strengths. Our findings reveal magnetic field strengths at the stellar surface typical of nonflaring PMS stars, ruling out the need for abnormally strong fields during flares. Both PMS and solar flares deviate from the L X–Φ law, with PMS flares exhibiting a more pronounced deviation, primarily due to their much larger active regions on the surface and larger flaring loop volumes above the surface compared to their solar counterparts. These deviations likely stem from the fact that powerful flares are driven by magnetic reconnection, while baseline X-ray emission may involve less efficient mechanisms like Alfvén wave heating. Our results also indicate a preference for dipolar magnetic loops in PMS flares, consistent with Zeeman–Doppler imaging of fully convective stars. This requirement for giant dipolar loops aligns with MHD predictions of strong dipoles supported by polar magnetic surface active regions in fast-rotating, fully convective stars.

Doppler velocity of m=1 high-latitude inertial mode over the last five sunspot cycles

A variety of solar global modes of oscillation in the inertial frequency range have been identified in maps of horizontal flows derived from GONG and HMI data. Among these, the high-latitude mode with azimuthal order m=1 (HL) has the largest amplitude and plays a role in shaping the Sun's differential rotation profile. We aim to study the evolution of the HL mode parameters, utilizing Dopplergrams from the Mount Wilson Observatory (MWO), GONG, and HMI, covering together five solar cycles since 1967. We calculated the averages of line-of-sight Doppler signals over longitude, weighted by the sine of longitude with respect to the central meridian, as a proxy for zonal velocity at the surface. We measured the mode's power and frequency from these zonal velocities at high latitudes in sliding time windows of three years. The HL mode is easily observed in the maps of zonal velocity at latitudes above 50 degrees, especially during solar minima. The mode parameters measured from the three independent data sets are consistent during their overlapping periods and agree with previous findings using HMI ring-diagram analysis. We find that the amplitude of the mode undergoes very large variations, taking maximum values at the start of solar cycles 21, 22, and 25, and during the rising phases of cycles 23 and 24. The mode amplitude is anticorrelated with the sunspot number (textrm corr =-0.50) but not correlated with the polar field strength. Over the period 1983--2022 the mode amplitude is strongly anticorrelated with the rotation rate at latitude $60^∘$ (textrm corr =-0.82), that is, with the rotation rate near the mode's critical latitude. The mode frequency variations are small and display no clear solar cycle periodicity above the noise level (∼ ± 3 nHz). Since about 1990, the mode frequency follows an overall decrease of ∼ 0.25 nHz/year, consistent with the long-term decrease of the angular velocity at $60^∘$ latitude. We have shown that the amplitude and frequency of the HL mode can be measured over the last five solar cycles, together with the line-of-sight projection of the velocity eigenfunction. We expect that these very long time series of the mode properties will be key to understand the dynamical interactions between the high-latitude modes, differential rotation, and (possibly) magnetic activity.

Exploring Magnetic Fields in Molecular Clouds through Denoising Diffusion Probabilistic Models

Abstract Accurately measuring magnetic field strength in the interstellar medium, including giant molecular clouds, remains a significant challenge. We present a machine learning approach using denoising diffusion probabilistic models (DDPMs) to estimate magnetic field strength from synthetic observables such as column density, orientation angles of the dust continuum polarization vector, and line-of-sight (LOS) nonthermal velocity dispersion. We trained three versions of the DDPM model: the 1-channel DDPM (using only column density), the 2-channel DDPM (incorporating both column density and polarization angles), and the 3-channel DDPM (which combines column density, polarization angles, and LOS nonthermal velocity dispersion). The code and trained model are available on GitHub at https://github.com/xuduo117/DDPM_Bmag. We assessed the models on both synthetic test samples and new simulation data that were outside the training set's distribution. The 3-channel DDPM consistently outperformed both the other DDPM variants and the power-law fitting approach based on column density alone, demonstrating its robustness in handling previously unseen data. Additionally, we compared the performance of the Davis–Chandrasekhar–Fermi (DCF) methods, both classical and modified, to the DDPM predictions. The classical DCF method overestimated the magnetic field strength by approximately an order of magnitude. Although the modified DCF method showed improvement over the classical version, it still fell short of the precision achieved by the 3-channel DDPM.

Landau levels induced by synthetic strain in plasmonic metasurface

The quantum Hall effect arises when electrons in a two-dimensional plane are subjected to a magnetic field, causing them to undergo cyclotron motion and form discrete energy levels, known as Landau levels. These levels play a critical role in condensed matter physics. However, practical limitations of applying a magnetic field have led to the introduction of pseudomagnetic fields, which can similarly induce Landau levels. Such pseudomagnetic fields are typically generated through synthetic strain, achieved by deforming geometric patterns, and have been applied to systems like graphene, photons, and phonon crystals. Building on previous research in electronics and optics, we present a plasmonic metasurface that induces Landau levels via synthetic strain in the microwave frequency range. This strain is realized by printing metal structures of specific shapes on a dielectric substrate using printed circuit board technology. The fundamental unit of the plasmonic metasurface is a C6 symmetric structure composed of six localized surface plasmon patches. By applying a displacement function along the transmission direction, we discretize the dispersion curve, leading to band degeneration and the emergence of edge states. The distribution of these edge states is influenced by the strength of the pseudomagnetic field, which is controlled by the magnitude of the displacement function. We validate our design through fabricated models and demonstrate the existence of edge states using near-field scanning experiments. Our work, which combines synthetic magnetic fields and plasmonic metasurface, provides valuable insights for the development and application of integrated photonic devices.

The role of machine learning in analyzing magnetic field localization and vortex generation in tetra-hybrid nanofluid: A numerical study

This research distinguishes itself by integrating machine learning algorithms to assess the impact of confined magnetic fields on vortex dynamics in hybrid nanofluid flow, through the inclusion of both vertical and horizontal magnetic field strips. Specifically, the study focuses on a vertical cavity with an aspect ratio of 1:5, where a bottom lid moves horizontally from left to right to drive the flow. We have applied a limited magnetic field consisting of vertical, and horizontal strips. The authors have developed MATLAB codes to implement an algorithm for solving the governing equations of the nanofluid flow and heat transfer. The algorithm is based on the Stream-Vorticity formulation and uses a finite difference method. The algorithm can examine how several parameters, such as magnetic field strength (0–300), nanoparticle volume fraction (0–20%), and Reynolds number (Re) (1–50), impact the characteristics of nanofluids in terms of flow and thermal properties. The results demonstrate that magnetic fields influence the stress distribution of the flow pattern and the temperature distribution. Further, the presence of a magnetic field also affects stress distribution. Moreover, it has been determined that the Nusselt number (Nu) experiences a 60% increase due to the magnetic field, while there is a remarkable rise attributed to the Re. Similarly, significant changes are observed in skin friction under both parameters. These findings carry implications for designing and operating devices.