Effect Of Magnetic Field Research Articles

The Effect of the Interplanetary Magnetic Field Clock Angle and the Latitude Location of the Intense Crustal Magnetic Field on the Ion Escape at Mars: An MHD Simulation Study

AbstractIn this paper, using a three‐dimensional multifluid MHD model, we studied the effects of the interplanetary magnetic field (IMF) clock angle and the latitude position of the intense crustal magnetic field (ICMF) on the escape of ions O+, , and at Mars. The main results are as follows: (a) The IMF clock angle affects the ion escape at Mars. When the ICMF is on the dayside, the ion escape rate reaches a maximum at the IMF clock angles close to 60°–90° and a minimum at the IMF clock angles close to 120°–150°, because the ICMF can change the topology of the magnetic field and affect the interaction between the solar wind and Mars. The difference between the maximum and minimum ion escape rates due to the IMF clock angle can reach over 50%. (b) Compared with the −ESW hemisphere, the escape flux of and in the +ESW hemisphere is more significant. However, O+ generally has a larger escape flux in the −ESW hemisphere. The different results in the ±ESW hemispheres might be due to the larger distribution of the hot oxygen corona, which changes the flow pattern of O+. (c) The latitude location of the ICMF can also affect the ion escape. When the ICMF is on the dayside, as the subsolar point varies from 25°S to 25°N, that is, the intense crustal magnetic field position keeps shifting southward, the ion escape rate shows a gradual increase.

The effects of surface fossil magnetic fields on massive star evolution: V. Models at low metallicity

Abstract At metallicities lower than that of the Small Magellanic Cloud, it remains essentially unexplored how fossil magnetic fields, forming large-scale magnetospheres, could affect the evolution of massive stars, thereby impacting the fundamental building blocks of the early Universe. We extend our stellar evolution model grid with representative calculations of main-sequence, single-star models with initial masses of 20 and 60 M⊙, including appropriate changes for low-metallicity environments (Z = 10−3–10−6). We scrutinise the magnetic, rotational, and chemical properties of the models. When lowering the metallicity, the rotational velocities can become higher and the tendency towards quasi-chemically homogeneous evolution increases. While magnetic fields aim to prevent the development of this evolutionary channel, the weakening stellar winds lead to less efficient magnetic braking in our models. Since the stellar radius is almost constant during a blueward evolution caused by efficient chemical mixing, the surface magnetic field strength remains unchanged in some models. We find core masses at the terminal-age main sequence between 22 and 52 M⊙ for initially 60 M⊙ models. This large difference is due to the vastly different chemical and rotational evolution. We conclude that in order to explain chemical species and, in particular, high nitrogen abundances in the early Universe, the adopted stellar models need to be under scrutiny. The assumptions regarding wind physics, chemical mixing, and magnetic fields will strongly impact the model predictions.

Improving plasma uniformity in the inductively coupled plasma by external magnetic field

To enhance etching efficiency and uniformity in process production, in this work, a two-dimensional fluid model was used to study the modulation effect of an external magnetic field on the argon–oxygen inductively coupled plasma (ICP). The study found that as the magnetic coil current increases, the electron density changes from center-high to uniform to edge-high distribution. The best plasma uniformity degree is 94%, obtained at a magnetic coil current of 10 A, which represents a 39% improvement over the unmagnetized ICP. The electric field reversal occurs during the transition from weak magnetization to strong magnetization. The electron temperature shows a single-peak to dual-peak to single-peak distribution during this period. In addition, we also found that gas pressure and oxygen ratio also impact magnetized plasma, where the effect of gas pressure on magnetized plasma is more significant than that of oxygen ratio. The results show that introducing an external magnetic field can significantly improve the plasma density and radial uniformity. This finding has contributed to enhancing plasma etching uniformity and optimizing etching processes.

Enhanced bioleaching of spent Li-ion batteries using A. ferrooxidans by application of external magnetic field

Recycling spent batteries is increasingly important for the sustainable use of Li-ion batteries (LIBs) and for countering the supply uncertainty of critical raw minerals (Li, Co, and Ni). Bioleaching, which uses microorganisms to extract valuable metals, is both economical and environmentally safe compared to other recycling methods, but its practical application is impaired by slow kinetics. Accelerating the process is a key for bioleaching spent LIBs on an industrial scale. Acidithiobacillus ferrooxidans (A. ferrooxidans), which thrives in extremely low pH conditions, has long been explored for bioleaching of spent LIBs. Metabolism of A. ferrooxidans involves the oxidation of magnetic Fe2+ and produces intracellular magnetic nanoparticles. The possibility of accelerating the leaching kinetics of A. ferrooxidans by the application of an external magnetic field is explored in this work. A weak static magnetic field is applied during the bioleaching of spent LIBs to recover Li, Ni, and Co using A. ferrooxidans. It is determined that 3 mT is the optimal field strength which allows the leaching efficiency of Li to reach 100% after only 2 days of leaching at a pulp density of 3 w/v % while without the external magnetic field, the leaching efficiency is limited to 57% even after 4 days. The leaching efficiency of Ni and Co also increases by nearly three-fold to >80% after 4 days of leaching. The proposed magnetic field-assisted bioleaching of spent LIBs using A. ferrooxidans substantially improves the leaching kinetics and thus the cost-effectiveness of the bioleaching process with minimal environmental impact, hence enabling environment-friendly recycling of raw materials that are increasingly becoming scarce. The positive effect of an external magnetic field on the metabolism of A. ferrooxidans demonstrated in this work provide a new set of tools to engineer the bioleaching process and the possibility for genetic modification of acidophile bacteria, especially targeted for magnetic enhancement.

Instability of double-diffusive magnetoconvection in a non-Newtonian fluid layer with cross-diffusion effects

The study explores the initiation of two-dimensional double-diffusive convection in a horizontal layer of an electrically conducting non-Newtonian Navier–Stokes–Voigt fluid, subjected to a uniform vertical magnetic field and cross-diffusion effects. The numerical results are presented by obtaining the analytical solutions for both steady and oscillatory onset scenarios. The viscoelastic nature of the fluid either delays or hastens the onset of oscillatory convection depending on the strength of solute concentration. The analysis also uncovers contradictions in the linear instability characteristics with and without cross-diffusion terms, even when other input parameters are identical. Under specific conditions, three novel phenomena are observed that are not typically seen in double-diffusive cases: (i) an electrically conducting Navier–Stokes–Voigt fluid layer, initially linearly stable in the presence of a magnetic field, can become destabilized with the addition of a heavy solute to the fluid's bottom; (ii) a stable double-diffusive electrically conducting Navier–Stokes–Voigt fluid layer can be destabilized by the application of a magnetic field; and (iii) the requirement of three critical values of the thermal Rayleigh number to determine linear instability, as opposed to the usual single value owing to the existence of disconnected closed convex oscillatory neutral curves. The results are shown to align with previously published findings in the limiting cases.

Enhancing Transport Processes in Stratified Fluids: Exploring Rotational and Stretching Effects Coupled with Magnetic Fields, Heat, Mass Transfer and Thermal/Solutal Slip

This research paper presents an in-depth investigation into the complex interactions governing stratified fluid flow in the presence of rotational and stretching phenomena, magnetic field influences, heat and mass transfer effects, and the incorporation of thermal and solutal-slips at fluid interfaces. Stratified fluid systems are commonly encountered in various natural and industrial processes, ranging from geophysical flows to chemical engineering applications, making a thorough understanding of these phenomena paramount.The study commences by formulating a comprehensive set of governing equations that account for the unique interplay of these multifaceted physical phenomena. Integrating thermal and solutal slip conditions at fluid interfaces introduces innovative prospects for precisely controlling and manipulating mass and heat transfer in these systems. This research paper extensively explores layered fluid dynamics, encompassing phenomena such as rotation and stretching, influences from magnetic fields, effects of heat and mass transfer, and the examination of thermal and solutal slip conditions. The insights obtained from this study not only enhance our comprehension of multi-physics fluid dynamics but also offer practical implications for streamlining processes across diverse fields. The principal findings and implications of this research can be summarized as follows: Various factors that affect fluid flow exhibit evident and discernible patterns.The mathematical model includes the Navier-Stokes equations with rotational and stretching terms, the Maxwell equations describing magnetic field effects, and the transport equations for heat and mass transfer. Additionally, thermal and solutal slip conditions at the fluid interfaces are incorporated to capture boundary layer dynamics.Numerical simulations are conducted to explore the intricate dynamics arising from this amalgamation of physical effects. The results reveal complex flow patterns, including stratification, boundary layer development, and vortical structures, offering insights into the behavior of fluids under the joint influence of rotational and stretching phenomena, magnetic fields, and thermal and solutal gradients. Furthermore, the impact of key parameters, such as rotation rate, stretching rate, magnetic field strength, and concentration gradients, is systematically analyzed to elucidate their effects on flow characteristics, heat and mass transfer rates, and concentration profiles within the stratified fluid layers. The Soret effect, or thermophoresis, causes nanoparticles to migrate away from hot regions due to fluid molecule flow and high energy levels. Elevating ξNt results in decreased heat and mass transfer. The Prandtl number shows minimal influence on heat and mass transfer when increased. The disk separation, and fluid viscosity, significantly affect the rotational spectrum. As the rotational parameter increases, heat and mass transfer decrease.

Mitigation of Screening Current-Induced Magnetic Field Effect in HTS Dipole Magnet Based on Coated Conductors: Overshooting and Shim Coil Study

Mitigation of Screening Current-Induced Magnetic Field Effect in HTS Dipole Magnet Based on Coated Conductors: Overshooting and Shim Coil Study

Predictable Gate-Field Control of Spin in Altermagnets with Spin-Layer Coupling.

Spintronics, a technology harnessing electron spin for information transmission, offers a promising avenue to surpass the limitations of conventional electronic devices. While the spin directly interacts with the magnetic field, its control through the electric field is generally more practical, and has become a focal point in the field. Here, we propose a mechanism to realize static and almost uniform effective magnetic field by gate-electric field. Our method employs two-dimensional altermagnets with valley-mediated spin-layer coupling (SLC), in which electronic states display valley-contrasted spin and layer polarization. For the low-energy valley electrons, a uniform gate field is approximately identical to a uniform magnetic field, leading to predictable control of spin. Through symmetry analysis and abinitio calculations, we predict altermagnetic monolayer Ca(CoN)_{2} and its family materials as potential candidates hosting SLC. We show that an almost uniform magnetic field (B_{z}) indeed is generated by gate field (E_{z}) in Ca(CoN)_{2} with B_{z}∝E_{z} in a wide range, and B_{z} reaches as high as about 10^{3} T when E_{z}=0.2 eV/Å. Furthermore, owing to the clean band structure and SLC, one can achieve perfect and switchable spin and valley currents and significant tunneling magnetoresistance in Ca(CoN)_{2} solely using the gate field. Our work provides new opportunities to generate predictable control of spin and design spintronic devices that can be controlled by purely electric means.

The Physiological Impact of Melatonin, Its Effect on the Course of Diseases and Their Therapy and the Effect of Magnetic Fields on Melatonin Secretion-Potential Common Pathways of Influence.

Melatonin is a relic, due to its millions-of-years-old presence in chemical reactions, found in evolutionarily diverse organisms. It has a multidirectional biological function. It controls diurnal rhythms, redox homeostasis, intestinal motor functions, mitochondrial biogenesis and fetal development and has antioxidant effects. It also has analgesic and therapeutic effects. The purpose of this paper is to describe the role of melatonin in vital processes occurring in interaction with the environment, with particular reference to various magnetic fields ubiquitous in the life of animate matter, especially radio frequency/extra low frequency (RF/ELF EMF) and static magnetic fields. The most important part of this article is to describe the potential effects of magnetic fields on melatonin secretion and the resulting possible health effects. Melatonin in some cases positively amplifies the electromagnetic signal, intensifying health effects, such as neurogenesis, analgesic effects or lowering blood pressure. In other cases, it is a stimulus that inhibits the processes of destruction and aggravation of lesions. Sometimes, however, in contrast to the beneficial effects of electromagnetic fields in therapy, they intensify pathogenic effects, as in multiple sclerosis by intensifying the inflammatory process.

Effects of hydrostatic pressure, aluminium composition, and external magnetic field on intersubband and intrasubband transitions characteristics in symmetric potential quantum wells

Aluminium composition (λ), magnetic field (B), and hydrostatic pressure (P) influences on magneto-optical (MO) properties of intra- and inter-subband transitions in GaAs/AlλGa1−λAs symmetric QWs for four models of confined optic phonons are studied and compared. The findings indicate: the MO characteristics of intra- and inter-subband transitions are significantly influenced by B, λ, and P for phonon absorption and emission. The e–p interaction intensity decreases as P increases, whereas it increases as λ increases. The influences of λ and P on phonon absorption are more significant than those on emission. E–p interaction intensity dependence on λ and P for intra-subband transitions is stronger than that for inter-subband ones. The e–p interaction in QWs is well described by Knipp–Reinecke and Huang–Zhu models. To reduce the influence of P on MO properties, we can increase T and λ or decrease B. At T≈600 K, the influence of P is insignificant and can be neglected.

Effect of the Magnetic Field and Rotation on Peristaltic Flow of A Carreau Fluid in Asymmetric Channel with Porous Medium

In this paper, the instability of the Carreau fluid was discussed in the asymmetric channel with a porous medium in the presence of a changing magnetic field and rotation. The Carreau fluid behaves like a non-Newtonian fluid, where it was found that the rotation has an effect on the stability of the fluid. Numerical methods are used to solve the equations, such as the perturbation method. Assumptions are used to analyze the flow. The effect of Hartmann number (Ha), Darcy number (Da), material fluid (We), magnetic field (β), capacitance ratio (∅) and rotation are calculated(Ω)Numerical results were calculated using MATHEMATICA program

Effects of magnetic field on CO2 hydrate phase equilibrium

Effects of magnetic field on CO2 hydrate phase equilibrium

The effect of the external magnetic field on the power of the laser passing through the magnetized plasma and the calculation of the radius of convergence and the investigation of the condition of the beam's filamentation in the Medium

In this article, the power of a laser passing through a magnetized plasma medium which is affected by an external magnetic field is calculated.The change in the intensity of the magnetic field and its rotation around the axis of laser beam propagation in the plasma, on the power of the passing beam is investigated.This work is done based on the indirect effect of the magnetic field on the density distribution of electrons in the plasma, which we can consider the density changes as changes in the refractive index of the medium, so the laser power in this case is different from the case where there is no magnetic field. Also, the condition of beam filamentation has been researched as one of the third-order nonlinear phenomena, and the convergence radius has been calculated under these conditions.

Role of Martian Crustal Fields in Ionospheric Electron Density Distribution and Subsequent South‐North Asymmetry: Insights From Multi‐Year MAVEN Observations During (MYs 33–36)

AbstractThis study uses Mars Atmosphere and Volatile EvolutioN observations of electron density and magnetic field for a period of four Martian years (MYs 33–36) (∼8 Earth years) to investigate the effects of Martian crustal magnetic fields on the distribution and variability of Mars' ionosphere. The results show a clear enhancement in electron density in the southern hemisphere in the region where the strong crustal magnetic fields are present with the longitudes between 120° and 240° (i.e., the central longitude), which is in agreement with previous studies. On the contrary, the corresponding northern hemisphere region in the central longitudes shows an exactly opposite behavior that the electron density is lower compared to the surrounding longitude regions. These effects are found to be primarily dayside phenomena. As opposed to dayside, the nightside electron density in the central longitudes are slightly reduced at altitudes below 200 km, compared to longitudes on its western and eastern sides. Above 200 km, the nightside effects are not very clear. Significant hemispheric asymmetry is observed in the longitude regions of enhanced crustal magnetic fields compared to other longitude regions during the daytime. This dayside south‐north asymmetry in the central longitude region is observed to be a constant feature across all seasons. However, on the nightside, the south‐north asymmetry remains more or less similar across all longitude regions, during all seasons implying a weakened control of the crustal fields over the nightside ionosphere. Even then, the northern hemisphere retains a stronger nightside ionosphere during all seasons except summer.

Modeling Ion Transport in the Upper Ionosphere of Mars: Exploring the Effect of Crustal Magnetic Fields

AbstractStatistically ion and electron densities are enhanced above strong crustal magnetic field regions according to measurements made by the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft. Plasma created by ionization of neutrals in the lower ionosphere (where chemistry dominates) flows upward and becomes trapped on closed magnetic field loops. Enhanced ion density in the ionosphere (particularly O2+) is associated with enhanced photochemical escape of atomic oxygen. This paper presents a quasi‐1D multi‐fluid time‐dependent model of the Martian ionosphere for nine ion species. Ionospheric temperatures are adopted but ion densities and velocities (along the field lines) are determined using a numerical solution of the continuity and momentum equations. Diurnal effects are explored by varying photoionization rates. Three crustal field cases are considered: a low altitude closed, a high altitude closed, and a high altitude open field line. Additionally, a case with no crustal field is modeled to provide a comparison between regions with and without crustal fields in the upper Martian ionosphere. Model results show higher ion and electron densities in the crustal field cases than in the purely induced field case. Additionally, we find that densities are generally higher on the closed field lines than on the open field lines, and ion velocities are generally up the field lines, away from the Martian surface. We also find that velocities are larger on the open field line case. We compare modeled density results to MAVEN data and find general agreement. Implications for atmospheric escape, particularly photochemical escape of O, are also discussed.

Irreversibility analysis of Jeffrey fluid flow in a sloping channel with Hall current, thermal radiation, and inclined magnetic field effects

Irreversibility analysis of Jeffrey fluid flow in a sloping channel with Hall current, thermal radiation, and inclined magnetic field effects

Magnetic field effects on the Kitaev model coupled to environment

Magnetic field effects on the Kitaev model coupled to environment

Tunnel transport problem for open multilayer nitride nanostructures with an applied constant magnetic field and time-dependent potential: An exact solution

A quantum mechanical theory for description of electronic quasistationary states in two-dimensional (2D) layered semiconductor nanostructure was developed. A constant external magnetic field B was directed along semiconductor layers. The presence of internal electric fields F originated from the potential barriers and wells in semiconductor layers was taken into account. The vector of F was directed perpendicularly to semiconductor layers. The interaction of tunneled electrons with a time-dependent electromagnetic fields was analyzed in detail. An approach to obtain an exact solution to the problem based on a combination of the Lewis-Riesenfeld method for complete Schrödinger equation and scattering theory was developed. Application of the scattering theory in combination with the -matrix and transfer-matrix methods allowed us to calculate the electron quasistationary spectra. Effects of magnetic field on the resonant energy and width of electronic quasistationary states as well as on the electronic conductivity were also discussed. Published by the American Physical Society 2024

The Effect of Static Magnetic Fields of Different Strengths and Polarities on Cytokine Production by Human Lymphocytes In Vitro.

In contrast to electromagnetic fields, static magnetic fields (SMFs) have not been extensively studied in terms of their potential health consequences. Although upward- and downward-oriented magnetic poles may cause various biological effects, only the pole with the upward orientation has been mainly investigated. Considering that the interaction of antigen-presenting cells (APCs) and T lymphocytes is crucial to trigger an immune response, we assessed the effect of long-term exposure of human T lymphocytes and dendritic cells (DCs) to moderate strength SMFs of different orientations focusing on the cytokine profile of activated T cells. Cultures of allogenic T lymphocytes and DCs (immature and matured by TLR3 and TLR7 agonists) were continuously exposed to four SMFs. The intensity of the applied field was 1 militesla (mT) or 56 mT of the upward- and downward-oriented pole of the SMF. Cell culture supernatants were assayed for IFN-γ, IL-4, IL-17, TNF-α, TNF-β, IL-1 β, IL-6, IL-8, and IL-10 by ELISA or flow cytometry. The upward-oriented 56 mT SMF significantly increased the release of IFN-γ and TNF-β (both p < 0.05) in the cell culture supernatants of T cells and immature DCs. In contrast, the same cultures exposed to the upward-oriented 1 mT SMF showed significantly elevated levels of IL-17 (p < 0.05). The levels of IL-4, TNF-α, IL-1 β, IL-6, IL-8, and IL-10 were not affected by the upward-oriented SMF. The downward-oriented 56 mT SMF increased TNF-α release when T cells were stimulated with mature DCs. The production of other cytokines was unchanged by the downward-oriented SMF. These findings demonstrate for the first time different in vitro biological effects of upward- and downward-oriented static magnetic fields on the cytokine production of T cells activated by DCs, helping to better understand SMF effects on the immune system and suggesting that the selective SMF effect on the immune response could have potential therapeutic effects in different immune-mediated disorders.

The influence of temperature and the magnetic field on Ni electrodeposition from citrate bath and its electrocatalytic performance towards hydrogen evolution reaction

The demand for energy surpasses the available supply, leading to various economic, social, and environmental consequences. Hydrogen is one of the most clean and renewable source for energy. Therefore, the electrocatalytic hydrogen evolution reaction (HER) presents a promising eco-friendly approach for generating sustainable hydrogen energy. However, in alkaline conditions, HER encounters slow kinetics due to challenges associated with hydrogen adsorption and hydrolysis. In this article, thin Ni films were synthesized using the electrodeposition technique from citrate electrolyte. Their suitability as electrocatalysts for the hydrogen evolution reaction (HER) in a 1 M NaOH solution was estimated. This research investigates how the uniform magnetic field and temperature affect the process of nickel electrodeposition from a citrate bath and its subsequent influence on surface morphology and catalytic properties for the hydrogen evolution reaction (HER). Additionally, alterations in surface material wettability were examined based on changing the temperature during using the magnetic field for the electrodeposition process and shows how this effect on the catalytic performance towards HER. The outputs show that using the magnetic field for fabrication of Ni thin films at room temperature enhances the surface morphology and its catalytic performance for HER. However, the study reveals that using the temperature for Ni electrodeposition improves its catalytic performance independently of the magnetic field, whereas combining temperature with the magnetic field for Ni thin film fabrication diminishes their catalytic performance for the hydrogen evolution reaction (HER). The nickel thin film produced at 25 °C under the influence of a magnetic field, whether parallel or perpendicular, demonstrates the lowest overpotential of − 268 mV to achieve a current density of 10 mA cm−2. Additionally, it exhibits the smallest Tafel slope values of 106 mV dec−1 and 128 mV dec−1 for the parallel (Bǁ) and perpendicular (BꞱ) directions, respectively. However, the magnetic field effect diminishes at elevated temperatures. Nickel thin films prepared at 35 °C under the influence of perpendicular (BꞱ) and parallel (Bǁ) directions exhibit higher overpotential values of − 314 mV and − 322 mV, respectively.