Increase Of Magnetic Field Intensity Research Articles

Effect of Electromagnetic Field Assistance on the Wear and Corrosion Resistance of Nickel-Based Coating by Laser Cladding

Offshore wind turbine generators usually demand higher requirements for key component materials because of the adverse working environment. Therefore, in this study, electromagnetic-assisted laser cladding technology was introduced to prepare the nickel-based composite coating on the Q345R matrix of wind turbine generator key component material. By means of Scanning Electron Microscope (SEM), X-ray diffraction (XRD), Energy Dispersive Spectrometer (EDS), the Vickers hardness tester, friction and wear tester, and electrochemical workstation, the effects of different magnetic field intensities on the macroscopic morphology, microstructure, phase composition, microhardness, wear resistance, and corrosion resistance of the coating were analyzed. The experimental results show that the addition of a magnetic field can effectively reduce the surface defects, improve the surface morphology, and not change the phase composition of the coating. With the increase in magnetic field intensity, the microstructure is gradually refined, and the average microhardness increases gradually, reaching a maximum of 944HV0.5 at 8 T. The wear resistance gradually increases with the increase in magnetic field intensity, especially when the magnetic field intensity reaches 12 T, the wear rate of the coating is reduced by 81.13%, and the corrosion current density is reduced by 43.7% compared with the coating without a magnetic field. The addition of an electromagnetic field can enhance the wear resistance and corrosion resistance of the nickel-based laser cladding layer.

Energy spectrum and magnetic susceptibility of the improved Pöschl-Teller potential

This study presents an analytical representation of the internal motion of a diatomic system using the improved Pöschl-Teller potential. The ro-vibrational energy spectrum is derived by solving the radial Schrödinger time independent wave equation (STIWE) under a 2D electromagnetic potential field. Additionally, an explicit equation for magnetic susceptibility is formulated from the internal partition function. The analytical models are used to investigate physical properties of CO (X1∑+), K2 (a3∑u+), BCl (X1∑+), and NaK (c3∑+) molecules. Average percentage absolute deviations (APAD) for the ro-vibrational energy spectrum are calculated as 0.1001 %, 0.5306 %, 1.2070 %, and 0.9779 %, respectively, compared to observed data. Numerical results are consistent with existing literature. Furthermore, the study reveals that the magnetic susceptibility of the system increases with temperature and decreases with an increase in magnetic field intensity, indicating its paramagnetic nature.

Computational Analysis of MHD Nanofluid Flow Across a Heated Square Cylinder with Heat Transfer and Entropy Generation

Abstract The mixed convection heat transfer of nanofluid flow in a heated square cylinder under the influence of a magnetic field is considered in this paper. ANSYS FLUENT computational fluid dynamics (CFD) software with a finite volume approach is used to solve unsteady two-dimensional Navier-Stokes and energy equations. The numerical solutions for velocity, thermal conductivity, temperature, Nusselt number and the effect of the parameters have been obtained; the intensity of the magnetic field, Richardson number, nanoparticle volume fraction, magnetic field parameter and nanoparticle diameter have also been investigated. The results indicate that as the dimensions of nanoparticles decrease, there is an observed augmentation in heat transfer rates from the square cylinder for a fixed volume concentration. This increment in heat transfer rate becomes approximately 2.5%–5% when nanoparticle size decreases from 100 nm to 30 nm for various particle volume fractions. Moreover, the magnitude of the Nusselt number enhances with the increase in magnetic field intensity and has the opposite impact on the Richardson number. The findings of the present study bear substantial implications for diverse applications, particularly in the realm of thermal management systems, where optimising heat transfer is crucial for enhancing the efficiency of electronic devices, cooling systems and other technological advancements.

Study on the static normal force of MRF in non-uniform magnetic field

Nowadays, many scholars have been studied the normal force of MRF in the uniform magnetic field. However, the research on the normal force of MRF in the non-uniform magnetic field is relatively limited. The non-uniform magnetic field can cause the MRF to generate normal force of different sizes and directions to cope with different working conditions, thus the normal force generated in the non-uniform magnetic field require more attention. In this paper, a theoretical model of the normal force of MRF in the non-uniform magnetic field was developed based on the enhanced magnetic dipole model. The normal force of MRF within a unit area can be calculated based on this theoretical model. However, the magnetic induction intensity is different at different locations of the non-uniform magnetic field, which leads to the normal force generated by the MRF are not accurately calculated. Therefore, it is necessary to use COMSOL to establish the material model of the MCR-302 plate rheometer and MRF to verify the accuracy of the proposed model. Then a flat-plate rheometer was used to test the static normal force of the MRF in the non-uniform magnetic field. Finally, the simulation and experimental data were compared. The results show that the simulation result with the experimental data is a good agreement, which verifies the reliability of the theoretical model. The static normal force of the MRF increases with the increase of volume fraction and magnetic field intensity.

Assessing the efficacy of magnetic water treatment: A concise review and experimental investigation

The utilization of magnetic water treatment has gained significant attention as a promising method for addressing scaling and water quality issues. This strategy has attracted interest due to its ability to potentially alter the behavior of dissolved particles in water. This investigation aimed to examine the impact of magnetic water treatment utilizing two different pipe materials, "iron pipe" and "PVC pipe", with a specific emphasis on the levels of total dissolved salts (TDS). Unexpectedly, the research findings indicate a positive correlation between the number of coil turns and the levels of TDS, which contradicts the popular belief that magnetic treatment would lead to a decrease in TDS. For instance, at a flow rate of 1 mL/s, TDS levels increase from an average of 265 ppm to roughly 277 ppm utilizing 500 and 2000 coil turns around an iron pipe, respectively. Similarly, when using a PVC pipe, TDS levels increase from around 263 ppm to 271 ppm as the magnetic field intensity increases. Furthermore, experiments carried out at an increased flow rate under a constant magnetic field strength show an inverse relationship with TDS. The TDS levels fall from 265 ppm to 261 ppm and from 263 ppm to 260 ppm as the flow rate rises from 1 mL/s to 6 mL/s for iron and PVC pipes, respectively. This intriguing phenomenon presents a challenge to long-held theories and highlights the complex relationship between magnetic fields, pipe materials, and water chemistry. Despite the unexpected results, the increase in the total dissolved salts indicates a possible improvement in reducing scaling, a common problem in fluid systems. In this discourse, this study analyzes the ramifications of these discoveries and underscores the necessity for additional investigation in order to elucidate the intricate mechanisms that underlie these interactions and enhance the efficacy of magnetic water treatment approaches. This research enhances the comprehension of water treatment strategies and emphasizes the significance of customizing procedures to suit individual scenarios in order to achieve efficient water quality control.

STUDY OF VELOCITY DISTRIBUTION OVER A NON-LINEAR STRETCHING IN PRESENCE OF VISCO-ELASTIC LIQUIDS

The study deals with the investigation of velocity of a boundary layer flow of a visco-elastic liquid over an non-linear stretching sheet. For analyzing velocity profiles have been employed for reducing the nonlinear model equation to a system of ordinary differential equations by employing analytical method velocity distribution are studied. It is found that with the increase of magnetic field intensity the fluid velocity at a particular point of the sheet the fluid velocity decreases. KEY WORDS: Visco-elastic, Newtonian fluid, viscosity

Active manipulation of the plasmonic induced asymmetric photonic spin Hall effect

The asymmetric photonic spin Hall effect (APSHE) induced by surface plasmon polaritons in a graphene-based structure is actively manipulated by external magnetic field and electric field. It is revealed that the spin-dependent splitting exhibits spatio-temporal asymmetric property due to the involvement of the anisotropic graphene. The peak of asymmetry degree in APSHE at the position of reflectance valley corresponds toward a smaller incident angle with the increase of magnetic field intensity or Fermi energy, which is attributed to the tunability of reflectance for the graphene-based structure. Based on the asymmetric splitting shift, a potential application is proposed for detecting low concentration gas molecules and the detection resolution can be dynamically tunable by changing the magnetic field intensity and Fermi energy. This study may provide a new reference in the fabrication of graphene-based plasmonic sensor devices.

Effect of magnetic field on the apparent viscosity of water-in-oil waxy crude oil emulsion

The application of the magnetic field to reduce the apparent viscosity of water-in-oil waxy crude oil emulsions holds significant potential. A novel integrated magnetic processing apparatus was developed. The effects of magnetic treatment conditions on the viscosity of waxy crude oil and water-in-oil waxy crude oil emulsions with different water cuts were experimentally investigated. The viscosity reduction induced by the magnetic field was more pronounced for the emulsion with a higher water cut. The viscosity reduction degree of the emulsion first increased and then decreased with the increase in magnetic field intensity and magnetic treatment temperature. The viscosity reduction degree of the emulsion had a slight correlation with the magnetic treatment time and magnetic field frequency. Microscopic observation demonstrated that water droplet aggregation occurred in the magnetically treated emulsion compared to the untreated emulsion. Mechanism analysis shows that the oscillation of asphaltene molecules at the oil–water interface, the orientational arrangement of asphaltene molecules in crude oil, and the generation of monomeric water molecules induced by magnetic field contribute to the reduction in the apparent viscosity of waxy crude oil and the aggregation of water droplets. The viscosity of the emulsion is thus decreased. The research results provide a theoretical basis for the field application of viscosity reduction for water-in-oil waxy crude oil emulsion by magnetic treatment technology.

Industrial-scale fabrication of FeSiBC cores with balanced soft magnetic properties by transverse magnetic field annealing and mixing of carbonyl iron powder

In this study, the effects of transverse magnetic field annealing and mixing fine powder on the soft magnetic properties of FeSiBC soft magnetic powder cores (SMPCs) are investigated. The results show that with the increase of transverse magnetic field intensity, the core loss of FeSiBC SMPCs decreases and then increases with a continuous increase in permeability compared to the zero magnetic field treatment. Wherein, the effective permeability of the powder cores is increased from 58.07 to 59.63 after transverse magnetic field annealing at a magnetic field intensity of 900 Gs and annealing temperature of 430 ℃. It shows that mixing the FeSiBC amorphous crushed powder with fine powder and transverse magnetic field annealing are effective ways to further promote amorphous SMPCs to meet the requirements of the development of electronic devices, and the prepared high-performance SMPCs also have a certain prospect of industrial application.

Analytical solutions for hyaluronic acid flow and heat transfer between joints with periodic oscillations under the magnetic field

Osteoarthritis (OA) is a globally prevalent disease that poses significant challenges to the daily work and life of patients. Viscosupplementation is one of the most commonly used drug treatments for OA, which involves injecting hyaluronic acid (HA) into the joint cavity to alleviate synovial inflammation. The current research aims to explore the rheological and thermal behavior of HA between joints by studying the axisymmetric squeezing flow and heat transfer of incompressible Maxwell fluid under the action of static magnetic field between two rigid spheres with partial wall slip. The analytical solutions for velocity and temperature are obtained by using the Laplace integral variational theory. Detailed explanations are provided on the effects of different fluid parameters on velocity and temperature, presented in the form of charts. It can be shown that as the magnetic field intensity increases, the viscosity of HA increases with the increasing of relaxation time, thereby fluid motion is weakened and a strong damping effect is produced. As the frequency of joints motion increases, the velocity distribution becomes more uniform in the central region, and the overall distribution deviates from a parabolic distribution. In addition, as Reynolds number, Prandtl number and squeezing depth increase, the heat transfer capacity of the fluid decreases, resulting in a lower temperature at the top wall and a higher temperature at the bottom wall. This study provides theoretical support for exploring the rheological and thermal behavior characteristics of HA in the treatment of OA.

The Design and Preparation of Permittivity-Adjustable FeNi@SrFe-MOF Composite Powders

When the thickness of the wave-absorbing material is low, there exists the problem of the narrow wave-absorbing frequency band, making it difficult to regulate the position of the wave-absorbing peak. In this study, FeNi@SrFe-MOF composite powders were synthesized using a hydrothermal method and a liquid-phase reduction method. The composite powder was spherical, with a particle size of about 50 μm–60 μm; the core layers of the powders were porous SrFe-MOF powders with permanent magnetization, and the outer layers were FeNi alloy nano-powder coatings with a particle size of 100 nm–120 nm, which took into account both the soft magnetization and the permanent magnetization properties of the composite powders. Additionally, a directional magnetic field was applied to the powder coating. By regulating the intensity and direction of the magnetic field, the electromagnetic parameters of the composite powder coating underwent sensitive changes, allowing for the precise regulation of the electromagnetic wave absorption performance of the composite powders. With the increase in magnetic field intensity, the ε′ value decreased significantly. The ε′ values were 8.56–7.35 for H453mT and 6.73–6.12 for H472mT. When no magnetic field was applied, the Snoke limit frequency of the μ′ value was 6.0 GHz. When the magnetic field intensity increased, the Snoke limit frequency of the μ′ value increased from 6.0 GHz, without the magnetic field, to 8.3 GHz; the Snoke limit of the composite powders was shattered. After the H453mT magnetic field regulation treatment, the powder coating exhibited good impedance matching characteristics with air. When the magnetic field intensity was 453mT and the thickness of the composite powders coating was 3.5 mm, the composite powders coating showed the strongest absorption peak when the R-value was −59 dB at 7.8 GHz, and the effective absorption bandwidth reached 3.2 GHz, exhibiting superb absorbent qualities. The wave absorption property of the coating can be sensitively changed by the magnetic field regulation treatment at the condition without changing the powder structure or coating structure, which provides a new strategy for the regulation of the wave absorption property and has broad application prospects.

Multi-ion magnetized sheath properties with non-extensive electron distribution

Magnetized plasma sheath plays an important role in semiconductor processing, material surface modification, film deposition, etc. In plasma experiments and discharge applications, multi-ion plasma consisting of more than two kinds of ions often exists. For a long range interacting plasma system, non-Maxwellian electrons can be described by the non-extensive distribution of Tsallis. In this work, a fluid model with one-dimensional spatial coordinates and three-dimensional velocity coordinates is established for the multi-ion plasma sheath. It is assumed that the electron velocity in the sheath follows a non-extensive distribution, and the background helium ions and different kinds of impurity ions are magnetized in a magnetic field with a certain tilt angle. The effects of non-extensive parameters, impurity ions and oblique magnetic field on the number density, velocity, wall potential and kinetic energy of ions in the multi-ion magnetic sheath are investigated by numerical simulation. The results show that in the helium-hydrogen or helium-argon mixed plasma sheath, the ionic velocity along the vertical wall direction decreases with the increase of the non-extensive parameters, the number density of ions and electrons in the sheath, the sheath thickness , and the kinetic energy of ions at the wall decrease. When the concentration of impurity ions increases, the kinetic energy of ions on the wall is independent of the type of ions. With the increase of magnetic field intensity, the number density of helium ions and the velocity along the vertical wall fluctuate along the sheath edge, and the fluctuation amplitude increases with the decrease of non-extensive parameters, while the heavy ions have no obvious fluctuation. In addition, the effects of the types and concentrations of impurity ions on the related properties of the sheath are also analyzed. With the increase of the magnetic field intensity, the number density and the velocity along the vertical wall direction fluctuate at the sheath edge, and the fluctuation amplitude increases with the decrease of the non-extensive parameter, whereas there are no significant fluctuations for heavy ions. In addition, when impurity ions are heavy ions, the absolute value of wall potential increases with the increase of impurity ion concentration and the decrease of non-extensibility parameters, and the kinetic energy of background ions increases at the wall surface. When the impurity ion is a light ion, the absolute value of the wall potential decreases with the increase of the impurity ion concentration and the decrease of the non-extensibility parameter, and the kinetic energy of the background ion at the wall decreases.

Magnetic field induced instability pattern evolution in an immiscible alloy

The magnetic field induced instability patterns have been observed in an undercooled immiscible Co–Cu alloy by an in situ magnetization measurement of the supercooled alloy melt. With the increase in magnetic field intensity and gradient, the undercooled immiscible melt experienced a transition from a core-shell structure to a layered structure at a lower field intensity and then a typical normal field instability pattern with the applied higher magnetic field gradient. Due to the different magnetic response ability of the separated phases in the presence of a magnetic field gradient, the transition of the morphology was complex, and its detailed investigations can provide important insight for better understanding of the ferrofluid and the creation of functional material. Furthermore, under an appropriate field gradient condition, it can achieve the subtle transitions between the diverse morphologies in an immiscible alloy.

Insight into acoustic wave-driven gas bubble dynamics in Williamson's fluid

This study's motivation on the behavior of a gas bubble and surrounding fluid during the collapse phase of an acoustic wave leads to the emission of light, which can be modelled using the Rayleigh-Plesset equation. The significant contribution to the major addition to the understanding of gas bubble dynamics in viscoelastic fluids. The results of the study have the potential to impact a wide range of applications, from sonar and underwater acoustic propagation to biomedical applications and industrial operations. Understanding the dynamics of acoustic wave-driven gas bubble oscillations in non-Newtonian fluids is crucial for various applications in medical imaging, therapy, and microfluidics. The aim of this study is to discover the conditions under which these bubbles can undergo sonoluminescence, the emission of light due to the collapse of bubbles under severe sonic pressure. The complex ordinary differential equation is solved numerically, and graphs are generated to evaluates various parameters such as velocity, radius, and pressure. A comparison with the viscous case is also presented to assess the influence of Newtonian and non-Newtonian fluids. A program designed by Mathematica software (13.0) “parametric NDSolve package” is used to solve the equations. The numerical solution supports the boundary conditions, indicating stability and reliability. Notably, the study identifies distinct fluctuations in the phase and stable characteristics associated with non-Newtonian effects. Interestingly, certain fluid parameters lead to discrete group modulation of radial excursions, revealing a novel and previously unknown phenomenon. It is concluded that Higher Reynolds numbers result in turbulent flow, which causes the bubble to enlarge and increase its volume. Furthermore the pressure gradient is affected by magnetic drag force, and as size of bubble increases, required pressure gradient to counteract the drag force also increases. As the magnetic field intensity increases, the velocity of the bubble decreases. Also, considering the implications of these results, the study explores their relevance to medical ultrasonography applications.

Integration of Magnetic-Field-Directed Self-Assembly-Based Cell Culture and Biosensing Platform for Improving hPSCs-Derived Neurons and Quantitative Detection of Neurotransmitter.

Despite the fact that human neural cell models have played significant roles in both research and cell replacement therapies for neurological diseases, the existing techniques for obtaining neurons from human pluripotent stem cells (hPSCs) are arduous and intricate. Additionally, the evaluation of neuron quality in the natural environment remains deficient. Consequently, we have developed a comprehensive platform utilizing magnetic-field-directed self-assembly (MDSA) of MXenes@Fe3O4 (M/F) nanocomposites. This platform facilitates the cultivation and in situ analysis of differentiated dopaminergic (DA) neurons. Our results showed that the introduction of M/F enhances neurite outgrowth and leads to the development of more intricate ramifications. Moreover, with the increase of magnetic field intensity, neurite outgrowth is further enhanced, and the proportion of differentiated mature neurons from hPSCs increases. This suggests that our platform promotes the maturation of neurons, emphasizing the crucial role of biophysical cues in expediting the differentiation process. The homogenization platform formed by MDSA of M/F nanocomposites exhibits high conductivity, leading to its exceptional performance in the real-time monitoring of the release of dopamine neurotransmitter from hPSC-derived DA neurons. Hence, this platform demonstrates significant potential for monitoring cell quality. In conclusion, our integrated platform, based on MDSA of M/F nanocomposites, offers a reliable and efficient means for the in vitro generation of human neurons with a controllable quality. The as-prepared platform holds potential for enhancing neuronal maturation and ensuring consistent cell quality, showing significant implications for in vitro biological research, disease modeling, and cell replacement therapy.

External magnetic field have significant effects on diversity of magnetotactic bacteria in sediments from Yangtze River, Chagan Lake and Zhalong Wetland in China

Magnetotactic bacteria (MTB) can rapidly relocate to optimal habitats by magnetotaxis, and play an important role in iron biogeochemical cycling. This study aimed to evaluate the contribution of the external magnetostatic field to the diversity of MTB in freshwater sediments from Yangtze River (Changjiang River, CJ), Chagan Lake (CGH) and Zhalong Wetland (ZL). The magnetic field intensity was tightly associated with the community richness of MTB in CJ, whereas it was closely related to the diversity of MTB in CGH and ZL (p < 0.05), elucidating a significant variation in the community composition of MTB. Magnetic exposure time appeared more significant correlation with community richness than diversity for MTB in CJ and CGH (p < 0.05), while an opposite relationship existed in ZL (p < 0.01). Herbaspirillum (93.81–96.48 %) dominated in the sediments of these surfacewatesr regardless of waterbody types, while it shifted to Magnetospirillum in ZL under 100 Gs magnetic field. The network connectivity and stability of MTB deteriorate with the increase of magnetic field intensity. Functional analysis showed that the Two-component system and ABC transporter system of MTB obviously responded to magnetic field intensity and exposure time. Our findings will pave the way to understanding the response mechanism of MTB community in freshwater sediments to the external magnetostatic field.

Experimental Investigation on Viscosity Change of Waxy Crude Oil Emulsion with Magnetic Field

The rheological properties of emulsions are complex, leading to serious flow assurance issues that affect the economical and safe operation of pipelines. It has been reported that applying magnetic treatment technology can effectively improve the flowability of waxy crude oil. The study aims to investigate the influence of magnetic treatment on the viscosity of waxy crude oil emulsions. A dynamic electromagnetic treatment device was designed. The dynamic magnetic treatment experiments of waxy crude oil emulsion were carried out to explore the effects of magnetic field intensity and magnetic field frequency on the viscosity change of waxy crude oil emulsion. Research results show that with four different magnetic field frequencies, the viscosity of the emulsion decreases initially and then increases with the increase in magnetic field intensity. The variation law of emulsion viscosity with magnetic field intensity is related to the magnetic field frequency. When the magnetic field frequency is 100 Hz, the highest and lowest viscosity variation rates are 7.91% and -7.36%, respectively, which occur at the magnetic field strength of 110 mT and 30 mT, respectively. It is believed that applying a higher field strength electromagnetic field to the emulsion is beneficial for viscosity reduction. The research findings can provide guidance for the further study of the viscosity reduction of waxy crude oil emulsion magnetic treatment technology.

Numerical analysis for the normal force of magnetorheological fluids

As one of the most important mechanical parameters of magnetorheological fluids (MRF), the normal force has been studied by a large number of researchers using various experimental equipment and methods. However, it is difficult to reveal the effects of particle microstructure characteristics on the normal force of MRF by experimental methods, especially for such factor as the particle size distribution. To advance this research area, a numerical method for calculating the normal force of MRF is proposed in this study. The accuracy of the simulation model is verified with the experimental results measured by a plate-plate magnetorheometer. The results show that the simulated values agree well with the experimental data, which indicates the feasibility of calculating the normal force of MRF using numerical methods and provides a new research idea for a more intuitive and comprehensive analysis of the normal force characteristics of MRF. Besides, the simulated data show that the increase in magnetic field intensity and particle volume fraction will sufficiently enhance the normal force of MRF and improve the response time of MRF. For the MRF with the same particle volume fraction, a decline in the average particle diameter will increase the normal force. Moreover, increasing the dispersion of particle size of MRF particles can also improve its normal force.

Application of Water-Based Ferrofluid for Water Electrolysis

A combination of renewable energies and water electrolysis has been attracting much attention as an environmentally-friendly method to produce hydrogen, which has been expected as promising future energy storage and carrier media. And micro-gravity induces the adsorption of gas-bubbles on the surface of electrodes and this leads the declination of water electrolysis. In the present study, a new method which has the potential to dramatically enhance the water electrolysis efficiency was proposed by utilizing the magnetic buoyancy. Using water-based ferrofluids as an electrolyte and directly electrolyzing them in the presence of inhomogeneous magnetic fields enhance the desorption of gas-bubbles adsorbed on electrodes.When non-magnetic bodies are placed in the ferrofluid and are exposed to an inhomogeneous magnetic field, the magnetic buoyancy force acts on the non-magnetic bodies. Because the gradient of the magnetic field gives the magnetic buoyancy force, the non-magnetic body moves as the non-magnetic body is ejected from the magnetic field. When the water-based ferrofluid is used as an electrolyte and magnets are placed nearby electrodes, the magnetic buoyancy force acts on the bubbles (H2 and O2) generated from the surface of the electrodes, resulting in the water electrolysis enhancement.However, the effect of the magnetic fields on the water electrolysis using the ferrofluid is not well understood. In the present study, to understand the effect of the magnetic field on the water electrolysis, the chronoamperometry measurements in the presence of the magnetic field was carried out. The results showed that the water electrolysis is found to be enhanced by increasing the magnetic field intensity due to the magnetic buoyancy force. The present study showed that our proposed method has a great potential to enhance the water electrolysis substantially.In addition, we investigated the effect of magnetic field strength on the water electrolysis process by a dynamic impedance method. The Nyquist plot was obtained by the dynamic impedance method. The tested electrolyte was a water-based ferrofluid adding Na2SO4 with 0.1 mol/L. When the magnetic field intensity increases, Z Re decreases, which represents that the resistance in the water electrolysis becomes smaller. The equivalent circuit fits the experimental data well, resulting in that it is possible to divide the whole resistance into the charge-transfer and solution resistances. The charge-transfer resistance dramatically decreases with the magnetic field strength, while the solution resistance doesn't change. This phenomenon explains that the magnetic buoyancy sufficiently enhances the bubble desorption, resulting in the water electrolysis enhancement.

The resonance between the electromagnetic field and electrons in the helicon plasma source of a magnetoplasma rocket engine

The helicon plasma source is of great significance for the magnetoplasma rocket engine (MPRE) to be used as an effective propulsion device. In this paper, a multi-fluid, two-dimensional, axisymmetric model coupled with the electromagnetic field was developed to simulate the helicon plasma source in the MPRE. The simulation results demonstrate that the operation mode of the helicon plasma source in the MPRE gradually converts to a high-order wave mode and the resonance between the electromagnetic field and electrons is observed; due to the resonance, the deposit power density inside the plasma increases significantly, and the plasma density is two orders of magnitude higher than that in the inductively coupled plasma source. As the magnetic field intensity increases, the helicon plasma source enters into a high-order wave mode, which suggests that the MPRE can improve the utilization rate of the working medium by a stronger magnetic field.