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Objective. To develop and validate a graphics processing unit (GPU) based superposition Monte Carlo (SMC) code for efficient and accurate dose calculation in magnetic fields. Approach. A series of mono-energy photons ranging from 25 keV to 7.7 MeV were simulated with EGSnrc in a water phantom to generate particle tracks database. SMC physics was extended with charged particle transport in magnetic fields and subsequently programmed on GPU as gSMC. Optimized simulation scheme was designed by combining variance reduction techniques to relieve the thread divergence issue in general GPU-MC codes and improve the calculation efficiency. The gSMC code's dose calculation accuracy and efficiency were assessed through both phantoms and patient cases. Main results. gSMC accurately calculated the dose in various phantoms for both B  = 0 T and B  = 1.5 T, and it matched EGSnrc well with a root mean square error of less than 1.0% for the entire depth dose region. Patient cases validation also showed a high dose agreement with EGSnrc with 3D gamma passing rate (2%/2 mm) large than 97% for all tested tumor sites. Combined with photon splitting and particle track repeating techniques, gSMC resolved the thread divergence issue and showed an efficiency gain of 186-304 relative to EGSnrc with 10 CPU threads. Significance. A GPU-superposition Monte Carlo code called gSMC was developed and validated for dose calculation in magnetic fields. The developed code's high calculation accuracy and efficiency make it suitable for dose calculation tasks in online adaptive radiotherapy with MR-LINAC., (© 2022 Institute of Physics and Engineering in Medicine.)

With the discovery of magnetoreceptor mechanisms in animals, it materialized the novel applications of controlling cell and animal behaviors using magnetic fields. T cells have shown to be sensitive to magnetic fields. Here, we reported that exposure to moderate SMFs (static magnetic fields) led to increased granule and cytokine secretion as well as ATP production and mitochondrial respiration from CD8 + T cells. These effects were inhibited by knocking down the Uqcrb and Ndufs6 genes of mitochondrial respiratory chain, whose transcriptions were regulated by candidate magnetoreceptor genes Isca1 and Cry1/Cry2. SMF exposure also promoted CD8 + T cell granule and cytokine secretion and repressed tumor growth in vivo. SMFs enhanced CD8 + T cell cytotoxicity, and the adoptive transfer into tumor-bearing mice resulted in enhanced antitumor effects. Collectively, our study suggests that moderate SMFs enhance CD8 + T cell cytotoxicity by promoting mitochondrial respiration and promoted the antitumor function of CD8 + T cells.

Increasing evidence shows that static magnetic fields (SMFs) can affect microbial growth metabolism, but the specific mechanism is still unclear. In this study, we have investigated the effect of moderate-strength SMFs on growth and vitamin K 2 biosynthesis of Flavobacterium sp. m1-14. First, we designed a series of different moderate-strength magnetic field intensities (0, 50, 100, 150, 190 mT) and exposure times (0, 24, 48, 72, 120 h). With the optimization of static magnetic field intensity and exposure time, biomass and vitamin K 2 production significantly increased compared to control. The maximum vitamin K 2 concentration and biomass were achieved when exposed to 100 mT SMF for 48 h; compared with the control group, they increased by 71.3% and 86.8%, respectively. Interestingly, it was found that both the cell viability and morphology changed significantly after SMF treatment. Second, the adenosine triphosphate (ATP) and glucose-6-phosphate dehydrogenase (G6PDH) metabolism is more vigorous after exposed to 100 mT SMF. This change affects the cell energy metabolism and fermentation behavior, and may partially explain the changes in bacterial biomass and vitamin K 2 production. The results show that moderate-strength SMFs may be a promising method to promote bacterial growth and secondary metabolite synthesis.

A possible approach to enhance the performance of microbial electrochemical system such as microbial fuel cells is to increase the conductivity of catalytic biofilms and thereby the direct extracellular electron transfer within the biofilms and from the electrode. In the present study, we evaluated the impact of static low-intensity magnetic field on the anodic biofilms in microbial fuel cells (MFCs). Results demonstrated that the application of a low-intensity magnetic field (105 and 150 mT) can significantly shorten the startup time and enhance the overall performance of single-chamber MFCs in terms of current density (300%) and power density (150%). In situ conductance evaluation indicated that short-term application of magnetic field can increase biofilm conductivity, although the long-term enhancements were likely results of increased conductivity of the anodic biofilms associated with enriched population of Geobacteraceae. The peak-manner response of conductivity over gate potentials and the positive response of mature biofilm conductance to low intensity of magnetic field support the redox conduction model of the conductive exoelectrogenic biofilms.

Objective: The tumor inhibition by magnetic fields (MFs) has been reported in many in vivo and in vitro studies, while clinical trials have been rare. This report aimed to evaluate the improvement of survival and general symptoms in advanced cancer patients treated with MFs., Subjects and Methods: In this study, we investigated 21 patients with advanced gastric cancer (AGC) treated with 420 r/min, 0.4-T low-frequency rotary MFs. The treatment area encompassed the primary tumor sites, metastatic sites, and metastatic lymph nodes. In addition, the patients were treated 2 h per day, 5 days per week for 6-12 weeks. The toxicity pilot human study was approved by the competent ethical committee. Toxicity and side effects were assessed according to the WHO criteria. The changes of general symptoms were analyzed during low-frequency rotary MFs treatment and 2 weeks after the end of therapy. Electrocardiogram, chest X-ray, physical examination, blood cell count and complete blood chemistry, biochemical, and kidney function tests were performed before and after the end of the treatment. All 21 patients were followed up by outpatient service or telephone interview., Results: Our results demonstrated that low-frequency rotary MFs improved abdominal pain in 9/21 (42.9%), nausea/vomiting in 4/21 (19.0%), weight loss in 11/21 (52.4%), ongoing blood loss in 2/21 (9.5%), physical strength in 5/21 (23.8%), and sleep quality in 4/21 (19.0%) patients. No severe toxicity and side effect were observed in our trial. The median survival time was 8.0 months (95% confidence interval, 5.190-10.810). The 1-year survival rate was 25.8%., Conclusion: Low-frequency rotary MFs may prolong survival and improve general symptom of AGC patients, as an effective, well-tolerated, and safe treatment choice., Competing Interests: There are no conflicts of interest

Magnetic field exposure is an accepted safe and effective modality for nerve injury. However, it is clinically used only as a supplement or salvage therapy at the later stage of treatment. Here, we used a planarian Girardia sinensis decapitated model to investigate beneficial effects of early rotary non-uniform magnetic fields (RMFs) exposure on central nervous regeneration. Our results clearly indicated that magnetic stimulation induced from early RMFs exposure significantly promoted neural regeneration of planarians. This stimulating effect is frequency and intensity dependent. Optimum effects were obtained when decapitated planarians were cultured at 20 °C, starved for 3 days before head-cutting, and treated with 6 Hz 0.02 T RMFs. At early regeneration stage, RMFs exposure eliminated edema around the wound and facilitated subsequent formation of blastema. It also accelerated cell proliferation and recovery of neuron functionality. Early RMFs exposure up-regulated expression of neural regeneration related proteins, EGR4 and Netrin 2, and mature nerve cell marker proteins, NSE and NPY. These results suggest that RMFs therapy produced early and significant benefit in central nervous regeneration, and should be clinically used at the early stage of neural regeneration, with appropriate optimal frequency and intensity., (© 2016 Wiley Periodicals, Inc.)

Neural stem cells (NSCs) proliferation can be influenced by repetitive transcranial magnetic stimulation (rTMS) in vivo via microRNA-106b-25 cluster, but the underlying mechanisms are poorly understood. This study investigated the involvement of microRNA-106b-25 cluster in the proliferation of NSCs after repetitive magnetic stimulation (rMS) in vitro. NSCs were stimulated by rMS (200/400/600/800/1000 pulses per day, with 10 Hz frequency and 50% maximum machine output) over a 3-day period. NSCs proliferation was detected by using ki-67 and EdU staining. Ki-67, p21, p57, cyclinD1, cyclinE, cyclinA, cdk2, cdk4 proteins and miR-106b, miR-93, miR-25 mRNAs were detected by Western blotting and qRT-PCR, respectively. The results showed that rMS could promote NSCs proliferation in a dose-dependent manner. The proportions of ki-67+ and Edu+ cells in 1000 pulses group were 20.65% and 4.00%, respectively, significantly higher than those in control group (9.25%, 2.05%). The expression levels of miR-106b and miR-93 were significantly upregulated in 600-1000 pulses groups compared with control group (P<0.05 or 0.01 for all). The expression levels of p21 protein were decreased significantly in 800/1000 pulses groups, and those of cyclinD1, cyclinA, cyclinE, cdk2 and cdk4 were obviously increased after rMS as compared with control group (P<0.05 or 0.01 for all). In conclusion, our findings suggested that rMS enhances the NSCs proliferation in vitro in a dose-dependent manner and miR-106b/p21/cdks/cyclins pathway was involved in the process.

It has been suggested that the line width of ions in molecular clouds is narrower than that of the co-existing neutral particles, which has been interpreted as an indication of the decoupling of neutral turbulence from magnetic fields within a partially ionized environment. We calculate the principal component analysis (PCA) correlation coefficients of CCH versus H |$^{13}$| CO |$^{+}$| and H |$^{13}$| CN versus H |$^{13}$| CO |$^{+}$|⁠. We find aside from H |$^{13}$| CN, CCH could also be strongly spatial correlated with H |$^{13}$| CO |$^{+}$| in high-mass star-forming regions. CCH and H |$^{13}$| CO |$^{+}$| line emissions are strongly spatial correlated with each other in 48 per cent sources with a PCA correlation coefficient over 0.7. So, we investigate the ambipolar diffusion (AD) effect using CCH and H |$^{13}$| CO |$^{+}$| lines as a neutral/ion pair in a sample of 129 high-mass star-forming clumps. We conduct a careful analysis of line widths of the CCH–H |$^{13}$| CO |$^{+}$| pair pixel-by-pixel in 12 sources, which show a strong correlation in CCH–H |$^{13}$| CO |$^+$| emission and no obvious outflows or multiple velocity components. The mean velocity dispersion of CCH is about the same as H |$^{13}$| CO |$^{+}$| in 12 sources. In low-density regions of most sources, CCH shows a broader velocity dispersion than H |$^{13}$| CO |$^{+}$|⁠. However, the AD effect is not significant from a statistical point of view. [ABSTRACT FROM AUTHOR]

While intensively studied, it remains unclear how the star formation (SF) in infrared dark clouds (IRDCs) compares to that of nearby clouds. We study G351.77-0.53 (henceforth G351), a cluster-forming filamentary IRDC. We begin by characterizing its young stellar object (YSO) content. Based on the average parallax of likely members, we obtain a Gaia distance of |$\sim \, 2.0\pm 0.14$|  kpc, resolving the literature distance ambiguity. Using our Herschel-derived N(H2) map, we measure a total gas mass of 10 200 M⊙ (within 11 pc2) and the average line-mass profile of the entire filament, which we model as |$\lambda =~1660 (w/\rm pc)^{0.62}\, \, {\rm M}_{\odot }\, \rm {pc}^{-1}$|⁠. At w < 0.63 pc, our λ profile is higher and has a steeper power-law index than λ profiles extracted in Orion A and most of its substructures. Based on the YSOs inside the filament area, we estimate the SF efficiency (SFE) and SF rate (SFR). We calculate a factor of 5 incompleteness correction for our YSO catalogue relative to Spitzer surveys of Orion A. The G351 SFE is ∼1.8 times lower than that of Orion A and lower than the median value for local clouds. We measure SFR and gas masses to estimate the efficiency per free-fall time, ϵff. We find that ϵff is ∼1.1 dex below the previously proposed mean local relation, and |$\sim \, 4.7\times$| below Orion A. These observations indicate that local SF-relations do not capture variations present in the Galaxy. We speculate that cloud youth and/or magnetic fields might account for the G351 inefficiency. [ABSTRACT FROM AUTHOR]

Here, we study a magnonic crystal made of low-damping yttrium iron garnet that utilizes pseudo-caustic spin wave beams generated from subwavelength square well features arranged in a two-dimensional array. The lattice symmetry and the angle between the caustic beam propagation direction and the applied magnetic field were tailored to optimize the interaction of spin waves with the engineered defects. A prominent, narrow 3 MHz feature with large rejection efficiency is observed in the spin wave transmission spectrum that could be useful as a narrowband notch filter, and time- and space-resolved Brillouin light scattering (BLS) measurements suggest that both caustic interference and edge effects may contribute to this notch feature. Furthermore, the BLS measurements show that caustics are generated efficiently at the laser ablated wells, and by tuning the frequency by 30 MHz, the caustic beam angles and, hence, the details of how the spin wave caustics hit the ablated wells change sufficiently to add and remove caustic beams, which can be used to create additional device functionality. The generation and conversion of caustic beams show promise for applications that require directional energy transport and for magnonic devices. [ABSTRACT FROM AUTHOR]

The pressure crashes observed in shot No. 71326 in the Experimental Advanced Superconducting Tokamak are numerically investigated with the three-dimensional, toroidal, and full resistive-magnetohydrodynamics code (CLT). Based on the experimental observations, the pressure crash is caused by the nonlinear evolution of the m/n = 2/1 double tearing mode (DTM), where n and m are the toroidal and poloidal mode numbers, respectively. However, we find that the m/n = 2/1 DTM is stable based on the safety factor (q) profile from the equilibrium code EFIT, which indicates that the original q profile is somewhat inconsistent with the actual profile due to q measurement uncertainty. Since there is no motional Stark effect diagnostic for this shot, the local information of the magnetic field is missing, which leads to the largest contribution to the discrepancy. If other information is perfectly known and the q profile is the only uncertainty, then we could provide some information for the EFIT reconstruction by comparing our simulation results with electron cyclotron emission signals to constrain the uncertainty of the q profile to a much smaller region. The influence of plasma rotation and the two-fluids effect is also discussed. [ABSTRACT FROM AUTHOR]

An innovative divertor concept, the fish tail divertor, is proposed in this paper, aimed at reducing the surface temperature on the tokamak divertor plate as well as that due to the edge localized modes. This new concept has been implemented in experiments to demonstrate its capability of strike point sweeping on the plate at a frequency range from 10 to 100 Hz by using an oscillating magnetic field. A strike point movement of 5–6 cm is achieved by applying a coil current of several percent of plasma current, leading to a significant reduction of divertor surface temperature. The result indicates a possible application in a fusion reactor. [ABSTRACT FROM AUTHOR]

The effects of compressibility and guiding field on the Kelvin–Helmholtz (KH) instability in a double resonant surface system are numerically investigated by using a compressible magnetohydrodynamics model. The linear growth rate and the nonlinear saturation amplitude are analyzed for different parameters. A transition from double tearing modes to the KH instability occurs depending on the compressibility and guiding field with a weak magnetic shear. These results may deepen our understanding of the properties of the KH instability with double resonant surfaces in both space and laboratory plasmas. [ABSTRACT FROM AUTHOR]

Spin waves in micrometer-sized, patterned Y-shaped Permalloy structures were studied using micro-focus Brillouin light scattering (BLS) with a magnetic field applied in-plane. For in-plane magnetized thin films and microstrips, the dispersion relations depend on the angle of the magnetization with respect to the microstrip axis. BLS measurements show that spin waves generated in the two arms that form the top of the Y structure can be channeled into a longer magnetic microstrip that forms the base when the applied field is oriented perpendicular to the long axis of the base. In this configuration, the base supports surface spin waves. A comparison of the BLS data with micromagnetic simulations reveals that low- k spin waves generated by a microstrip antenna in the arms are converted to higher- k spin waves in the base, which may be useful for nanomagnonic applications. [ABSTRACT FROM AUTHOR]

The equilibrium of the Chinese first quasi-axisymmetric stellarator (CFQS) has been investigated by the HINT code. It is found that the stochastization of magnetic field lines expands with the increase in the volume-averaged beta value 〈β〉 in the plasma boundary. In the high-β regime, the generation of large magnetic islands at rational surfaces not only leads to an effective shrinkage of the plasma confinement region but also increases the outward shift of the magnetic axis. With bootstrap current effects, the low-order islands spread over the whole plasma area, leading to a stochastization of magnetic field lines due to island chain overlapping. However, for a flat pressure profile, the magnetic islands are significantly suppressed so that the magnetic surfaces can be fairly maintained. Moreover, the magnetohydrodynamic (MHD) instabilities in the optimized CFQS configurations have been simulated by the MEGA code. The linear properties of unstable resistive MHD modes are studied. The results show that in the CFQS the main MHD behaviour is dominated by the resistive ballooning modes with strong mode coupling. The mode structure and resistivity scaling are consistent with related theories. [ABSTRACT FROM AUTHOR]

In this paper, we report new results of spectroscopic observations of γ-ray blazar S5 0716+714 from 2019 September to 2020 March with the 2.4 m optical telescope at Lijiang Observatory of Yunnan Observatories. The median cadence of observations is ∼1 day. During the second observation period (Epoch2), the observational data reveal an extremely bright state and a bluer-when-brighter (BWB) chromatism. The BWB trend of Epoch2 differs significantly from that of the first observation period (Epoch1). A significantly brightness-dependent BWB chromatism emerges in the total data of Epoch1 and Epoch2. The BWB trend becomes weaker toward the brighter states, and likely becomes saturated at the highest state. Based on a log-parabolic function, a power law of synchrotron peak flux and frequency νp, and a power law of the curvature of synchrotron spectrum and its νp, simulation well reproduces the brightness-dependent BWB trend of S5 0716+714. The BWB trend is seemingly controlled by the shift of νp with respect to the observational window, and effectively may be dominated by the variations of electron average energy and magnetic field in the emitting region. [ABSTRACT FROM AUTHOR]

A set of Observing System Simulation Experiments (OSSEs) are performed to assess the impact of assimilating Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) electron density profiles and ground-based Global Navigation Satellite System (GNSS) total electron content (TEC) observations in a whole atmosphere data assimilation system. The OSSEs are performed using the Whole Atmosphere Community Climate Model with thermosphere-ionosphere eXtension (WACCMX) with data assimilation provided by the Data Assimilation Research Testbed (DART) ensemble adjustment Kalman filter. Results from the OSSEs demonstrate that the assimilation of ionosphere observations improves the short-term (1 hr) forecasts and analyses. The OSSEs show that the short-term forecasts and analyses are further improved when the ionosphere observations adjust the thermosphere neutral composition and temperature in addition to the ionosphere electron density. Based on an initialized forecast experiment, we find that adjusting the thermosphere neutral composition and temperature also leads to improved forecast skill in the ionosphere on longer time scales (i.e., beyond 1 hr). Additionally, it is shown that using a 1 hr data assimilation cycle, and removal of second-order divergence damping inWACCMX+DART significantly improves tidal amplitudes, which were previously found to be too small. These initial results represent the first whole atmosphere data assimilation system with capabilities to assimilate observations from the troposphere to the ionosphere-thermosphere. [ABSTRACT FROM AUTHOR]

A magnetic field configuration of an island divertor for a quasi-axisymmetric stellarator (CFQS) is proposed. The configuration incorporates large islands surrounding the core confinement region. The interface between the core region and the peripheral region of the island divertor is a clear magnetic separatrix similar to a tokamak divertor. The structure of divertor magnetic field lines is very regular without stochasticity and the connection length is sufficiently long for good divertor performance. Such a divertor configuration is produced in the magnetic field configuration for the CFQS device, which is now under construction in China. [ABSTRACT FROM AUTHOR]

Density sweeping-down experiments have been performed in order to investigate the electron dynamics and the effects on instabilities such as magnetohydrodynamics (MHD) in the low collisionality regime in the Experimental Advanced Superconducting Tokamak (EAST). It is found that an electrostatic instability is always excited which is recognized as the anomalous Doppler instability (ADI). The ADI is characterized by the stair-stepping electron cyclotron emission (ECE), converting the parallel energy to the perpendicular component of energetic electrons in the direction of the magnetic field. The background electron temperature profile is redistributed which results in the gradient change in the core. Non-negligible bootstrap current causes the loop voltage decrease. The bootstrap current is dissipated by the bursting MHD instability which is explained as the Alfvén-acoustic mode. Analysis indicates that bulk electrons are easily trapped in the steepened temperature gradient region, intensifying the asymmetry of electron velocity distribution in the parallel direction and creating the bootstrap current in the low-collisionality regime. In particular, it is shown that the global Alfvén-acoustic mode dramatically removes trapped electrons and quenches the bootstrap current, which is the main limit for the bootstrap current life. [ABSTRACT FROM AUTHOR]

Based on the magnetic field configuration of the Chinese First Quasi-axisymmetric Stellarator (CFQS) device, three types of orbits such as the passing orbit, blocked trapped orbit, and localized trapped orbit are simulated using the Boris algorithm. Also, the orbital topology, orbit transition, and loss characteristics of these particles under different initial conditions are studied in this paper. It is found that there exists a transition from blocked trapped orbits to localized trapped orbits due to small continuous helical ripples. This phenomenon is analyzed as follows: we define the angle between the particle drift velocity ( v → D ) and the radial direction ( ρ ^ ) as β. If the blocked-localized transition appears in the region where β > 9 0 ○ , the localized particles will return to the blocked particles and be constrained. However, if the blocked-localized transition happens in the region where β < 9 0 ○ , localized particles will drift out of the last closed flux surface and be lost. The simulation results show that the loss of localized particles in the CFQS is mainly located in some specific regions within the vicinity of the toroidal angle φ = 0 ○ , 18 0 ○ and the poloidal angle θ = 9 0 ○ . [ABSTRACT FROM AUTHOR]

Electronic band structures and spin states of the InAs/GaAs quantum dots (QDs) induced by the wetting-layer fluctuation were investigated by employing the technique of time-resolved Kerr rotation (TRKR) with and without magnetic field. Sign change of the Kerr rotation signal was unambiguously observed when only the wavelength of the pump/probe light was scanned. By carefully examining the dependence of TRKR signal on the excitation wavelength and magnetic field as well as photoluminescence and reflectance spectra, the physical origin causing the sign change of the Kerr signal is uncovered. It is due to the resonant excitations of electrons with opposite spin orientations at heavy- (hh) and light-hole (lh) subbands, respectively, since there is a large enough energy separation in QDs for the excitation laser pulses. This measurement also leads to a precise determination of the energy separation between the hh and lh subbands near k = 0 point in the dots. [ABSTRACT FROM AUTHOR]

The ferromagnetic exchange interaction between Co and Mn in Heusler alloys has been phenomenologically investigated by analyzing the composition dependence of the magnetic moment and the Curie temperature in a series of quaternary CuCoMnAl alloys. The curves of the composition dependence of the magnetic moment show an interesting valleylike profile and their minima are positioned at different Co contents for different Mn concentrations. The ferromagnetic Co–Mn exchange interaction is a short-range effect which is only effective at the nearest-neighbor distance. At this distance, the exchange interaction can be further enhanced by a Mn-rich composition, but it might be destroyed by the lattice distortion due to the martensitic transformation. [ABSTRACT FROM AUTHOR]

A new linear plasma device LEAD (Linear experimental advanced device) has been built in Southwest Institute of Physics (SWIP) in China. One of the most notable features of LEAD is the highly flexible and customizable magnetic field configurations, such as highly-uniform field, convergent field, divergent field and cusp field. In this article, we present the design of the magnetic configurations, taking the topology of the magnets, the three-stage vacuum chamber and the magnetic requirements of plasma sources into account. The interplay between the magnetic shielding box of the matching network and the main magnetic field inside the vacuum chamber is evaluated to ensure both a tolerable influence on main magnetic field and an effective magnetic shielding for the automatic impedance matching box in helicon source. [ABSTRACT FROM AUTHOR]

Low‐energy ions of ionospheric origin with energies below 10s of electron volt dominate most of the volume and mass of the terrestrial magnetosphere. However, sunlit spacecraft often become positively charged to several 10s of volts, which prevents low‐energy ions from reaching the particle detectors on the spacecraft. Magnetospheric Multiscale spacecraft (MMS) observations show that ultralow‐frequency (ULF) waves drive low‐energy ions to drift in the E × B direction with a drift velocity equal to VE × B, and low‐energy ions were accelerated to sufficient total energy to be measured by the MMS/Fast Plasma Investigation Dual Ion Spectrometers. The maximum low‐energy ion energy flux peak seen in MMS1's dual ion spectrometer measurements agreed well with the theoretical calculation of H+ ion E × B drift energy. The density of ions in the energy range below minimum energy threshold was between 1 and 3 cm−3 in the magnetosphere subsolar region in this event. Plain Language Summary: Low‐energy ions of ionospheric origin dominate most of the volume and mass of the terrestrial magnetosphere. The amount of low‐energy ions that exist and the way they are distributed are open areas of study important to understanding the magnetized plasma environment surrounding Earth. Magnetospheric Multiscale spacecraft (MMS) is a four‐spacecraft mission carrying numerous instruments for characterizing the particles and fields making up this environment and which can be applied to investigating low‐energy ions. In this study, we found an event based on the MMS data showing that ultralow‐frequency waves drive low‐energy ions to drift in the direction normal to the plane defined by the electric and magnetic fields. This charged particle motion is called the E × B drift. During this event, the observations taken by the MMS from a distance of 64,000 km in space were consistent with the theoretical calculation of the charged particle E × B drift. The results were applied to show density of low‐energy ions in the subsolar magnetosphere region during this event was in the range of 1 to 3 cm−3. This event provides evidence for the E × B drift action based on magnetospheric particle and field observations that can be further applied to detect low‐energy ions in other magnetospheric locations. Key Points: An ultralow‐frequency wave and correlated low‐energy ion monoenergetic acceleration was observed by MMS1The maximum ion flux energy level detected by MMS1 DIS agreed well with the theoretical calculation of H+ ion E × B drift energyThe density of low‐energy ions with energy below minimum energy threshold was between 1 and 3 cm−3 in the magnetosphere subsolar region [ABSTRACT FROM AUTHOR]

The effects of Ni substitution on the magnetic properties and magnetocaloric effect (MCE) of (Mn1-xNix)3Sn2 compounds (x=0–0.5) have been investigated by x-ray diffraction and magnetization measurements. It was found that Ni substitution decreases the crystal cell volume and the magnetic transition temperatures compared with pure Mn3Sn2. The MCE for all samples has been calculated from the magnetization data in terms of the isothermal magnetic entropy change ΔSM. The maximum values of ΔSMmax at the magnetic phase transition temperatures resulting from a change in magnetic field of ΔH=5 T were found to be 28.2 mJ/cm3 K for Mn3Sn2 (TC1∼257 K), increasing to 31.2 mJ/cm3 K for (Mn0.9Ni0.1)3Sn2 (TC∼167 K). [ABSTRACT FROM AUTHOR]

In the process of micro beam plasma welding of thin-walled parts, gravity and surface tension make a molten metal flow downward, sometimes causing a bad formation. To solve this problem, a new external magnetic field-controlled method based on the eddy current principle was proposed. The distribution of the magnetic flux density, the induced current density, and the Lorentz force on a 4 mm stainless steel AISI 304 thin plate was examined using different oscillation frequencies (1, 5, 10 kHz) of the magnetic field with the finite element package COMSOL Multiphysics 5.0. The higher frequency was found to be more helpful to create greater electromagnetic force. This study examined the single-pass and three-layer welding of the 4-mm-thick stainless steel AISI 304 with different magnetic fields (3~12 mT) at 10 kHz. The results show that 7- and 8-mT magnetic fields were effective in suppressing the sagging of the cladding layer. [ABSTRACT FROM AUTHOR]

The tribological properties of Ni-Co alloy coating have been studied extensively. We combined laser processing and magnetic field to improve tribological performance of Ni-Co alloy coating. The relationship between magnetic field and tribological properties was investigated and revealed the anti-friction law of magnetized microtextured/nanotextured surface. A laser direct writing system was used to fabricate microtexture/nanotexture on Ni-Co coating surface, and then the samples were magnetized by a permanent magnet. The tribological properties of the coating were characterised and showed that the magnetic field can significantly reduce the friction forces of Ni-Co coating surface. After magnetizing treatment in a magnetic field, the laser processed coating surface has a much lower friction force than the coating without laser processing; therefore, both laser processing parameters and magnetic flux density could influence the tribological properties of Ni-Co coating surface. [ABSTRACT FROM AUTHOR]

The longitudinal magnetic-field dependence of quantized spin waves in ordered permalloy nanowire arrays in two dimensions (2D) has been studied by Brillouin spectroscopy. The results were analyzed on the basis of collective spin waves in a hexagonal 2D nanowire array and compared with the results obtained from an analysis of spin waves in an isolated wire. It is found that only the lowest-frequency spin-wave mode of an isolated nanowire is marginally influenced by the presence of neighboring nanowires. These findings are significant for the theoretical understanding and the future technological utilization of magnetic nanowires. [ABSTRACT FROM AUTHOR]

We report the observation of an exchange biasing of ferromagnetic Cr-doped GaN films by an antiferromagnetic MnO overlayer. The center of the magnetic hysteresis loop shifts to a negative magnetic field by ∼70 Oe when measured after a positive field cooling. An enhancement of the coercive field of the Cr-doped GaN film is also found when the exchange-biasing MnO overlayer is present. The mechanism responsible for the exchange bias is attributed to the exchange coupling at the ferromagnetic Cr–GaN/antiferromagnetic MnO interface. [ABSTRACT FROM AUTHOR]

Presents information on a study which analyzed the magnetic field dependence of the tunneling current in gallium arsenide (GaAs)/AlAs double barrier structures. Measurements done in liquid helium with magnetic fields; Single large resonant tunneling peak; Details of the GaAs tunneling structures.

The laser action in one-dimensional (1-D) disordered media composed of magnetically active semiconductor material is investigated by simultaneously solving Maxwell's equations and rate equations of electronic population. An analysis model is proposed to explain that emission spectrum from the semiconductor-based disordered media can be tunable by external magnetic fields. The dielectric constant of the semiconductor would be modified in different frequency ranges due to the magneto-optical Voigt effect which has significant influence on the laser action. Results indicate that the threshold characteristics can be externally controlled by varying the external magnetic field and pump profile, which provides an effective mode selection method in disordered media. [ABSTRACT FROM AUTHOR]

This paper investigates the operating characteristics of hybrid-flux-modulated motor with amorphous magnetic material core using 3D time-stepping finite element method. In the proposed hybrid-flux-modulated motor, the radial-iron segments and axial-iron segments in the air-gap are used to modulate the magnetic field, the concentrated stator windings are built to reduce the end length, therefore to reduce copper losses, the stator core and the modulated segments are built with the amorphous magnetic material to reduce the core losses and therefore to enhance the efficiency of the motor. The flux distribution, electromotive force waveforms, cogging torque, output torque, core losses and efficiency of the proposed hybrid-flux-modulated motor have been investigated. All studies show that the efficiency of the proposed hybrid-flux-modulated motor can be improved by utilising amorphous magnetic material and the motor is potential to apply in variable speed driving applications. [ABSTRACT FROM AUTHOR]

We highlight distinct and systematic observational features of magnetic field morphologies in polarized submm dust continuum. We illustrate this with specific examples and show statistical trends from a sample of 50 star-forming regions. [ABSTRACT FROM AUTHOR]

Superconductor-ferromagnetic (FN) metamaterial with effective magnetic shielding and transmittal properties that allow the cloaking and transferring of static magnetic fields has been introduced. Most metamaterials consist of different arrangements of superconducting and ferromagnetic materials whose performance and feasibility mainly depend on the involved materials, their geometrical distribution and the permeability of each. In this paper, combining the method of transformation optics with the design of metamaterials, we experimentally demonstrated a superconductor-FM metamaterial system, composed of two coaxial cylinders of different lengths, to investigate the influence of the length and the properties of superconducting material on the magnetic transferring properties of the magnetic field produced by the permanent magnets. By comparing the transmittal magnetic field of different cases, the optimal structure has been ultimately achieved in terms of calculating the transmitted magnetic field ratios. The insights attained by the present study are aimed to provide useful implications for the design of wireless energy transmission and increasing the efficiency of magnetic transmittal devices. [ABSTRACT FROM AUTHOR]

We report on an instrument for applying ac and dc magnetic fields by capturing the flux from a rotating permanent magnet and projecting it between two adjustable pole pieces. This can be an alternative to standard electromagnets for experiments with small samples or in probe stations in which an applied magnetic field is needed locally, with advantages that include a compact form-factor, very low power requirements and dissipation as well as fast field sweep rates. This flux capture instrument (FLUXCAP) can produce fields from -400 to +400 mT, with field resolution less than 1 mT. It generates static magnetic fields as well as ramped fields, with ramping rates as high as 10 T/s. We demonstrate the use of this apparatus for studying the magnetotransport properties of spin-valve nanopillars, a nanoscale device that exhibits giant magnetoresistance. [ABSTRACT FROM AUTHOR]

Abstract: The coupled magnetic plasmons (CMPs) has been investigated in an active system composed of coupled metamaterial and quantum dots. By introducing a full-quantum description of CMPs, the interaction Hamiltonian of the active system was obtained, through which the stimulated emission could be investigated. The results showed that the CMP amplification by the stimulated emission radiation could be achieved under certain conditions. This may be used to work as a CMP source in the integrated optics and nano-photonics. [Copyright &y& Elsevier]

A study of radial propagation and electric fields induced by charge separation in blob-like structures has been performed in a non-confined cylindrical electron cyclotron resonance heating plasma on Q-shu University Experiment with a Steady-State Spherical Tokamak using a fast-speed camera and a Langmuir probe. The radial propagation of the blob-like structures is found to be driven by E × B drift. Moreover, these blob-like structures were found to have been accelerated, and the property of the measured radial velocities agrees with the previously proposed model [C. Theiler et al., Phys. Rev. Lett. 103, 065001 (2009)]. Although the dependence of the radial velocity on the connection length of the magnetic field appeared to be different, a plausible explanation based on enhanced short-circuiting of the current path can be proposed. [ABSTRACT FROM AUTHOR]

The spin polarization (P) of high-density InSb two-dimensional electron systems (2DESs) has been measured using both parallel and tilted magnetic fields. P is found to exhibit a superlinear increase with the total field B. This P-B nonlinearity results in a difference in spin susceptibility between its real value χs and χgm / m*g* (m* and g* are the effective mass and g factor, respectively) as routinely used in experiments. We demonstrate that such a P-B nonlinearity originates from the linearly P-dependent g* due to the exchange coupling of electrons rather than from the electron correlation as predicted for the low-density 2DES. [ABSTRACT FROM AUTHOR]

The magnetization, Raman spectroscopy, and ferroelectricity of multiferroic GdMn2O5 as a function of temperature and magnetic field are investigated. The complicated magnetic transitions at low temperatures are featured with anomalous Raman mode shifts, dielectric response, and ferroelectricity generation, indicating the significant spin–phonon coupling. It is argued that this coupling is possibly responsible for the electrical polarization generation associated with the incommensurate–commensurate transition. [ABSTRACT FROM AUTHOR]

The current controversy over the need for an experimental test of String Theory is considered. We report recent experiments on quasi-bound electrons in crossed electric and magnetic fields, in which states of very large electric dipole moment are excited. The excited electron is confined to one side of the atomic nucleus in the outer well of a controllable double-well potential. These states are discussed in relation to a recent theoretical proposal to test the spatial non-commutativity underpinning String Theory by studying Penning orbits of Rydberg atoms in crossed electric and magnetic fields. [ABSTRACT FROM AUTHOR]

Based on the plane wave expansion method, the complete band gaps of two-dimensional terahertz photonic crystals with typical structures are optimized through varying structural parameters. During our calculation, two kinds of lattice structures that are very promising for the materials of terahertz components are found and some interesting phenomena that were not reported in the former papers are also presented. Using the finite difference time domain method, we simulated the electromagnetic field distribution of THz waves in a PC splitter. And by the plane wave expansion method, we achieved the dispersion relation and defect modes in a rotated PC waveguide. These results provide a useful guide and a theoretical basis for the developments of THz functional components. [ABSTRACT FROM AUTHOR]

The conductivity of manganese perovskite (La0·82Sr0·18MnO3) fine particles compacts of different densities has been investigated. An evident percolation behavior, which can work only with the aid of the double-exchange interaction, has been observed. The critical compactness and the threshold for the percolation have been estimated. Some concepts have been developed to study the bond continuum percolation. By applying an external magnetic field, a field-induced enhancement in percolation of the granular material has been obtained, and it was also found that the effect increases with decreasing compactness and temperature. [ABSTRACT FROM AUTHOR]

Abstract: Large negative magnetoresistance (MR) has been observed in the broken cold-pressed CrO2 powder samples near the room temperature, which is ascribed to the magnetic field-induced mechanical contact variation. This large, room-temperature negative MR might easily lead to a wrong conclusion that the spin-polarization is still very high at high temperatures. This observation may also point to the possibility to develop field sensors based on the mechanical MR. [Copyright &y& Elsevier]

The thin films of Co-doped and Co3O4-doped dielectric LaAlO3 (LAO) by co-ablation of magnetic metal Co and dielectric LAO on Pt – Ti – SiO2 – Si substrates have been prepared by pulsed laser deposition. A significant enhancement of dielectric constant of LAO upon doping of Co and cobalt oxide clusters is observed. Furthermore, modulation of the dielectric constant of the thin films by applying a magnetic field is verified, obviously due to the ferromagnetism of Co metal and Co oxide clusters embedded in the LAO thin films. A series of microstructural and dielectric characterizations on the as-prepared thin films have been performed and the mechanism underlying the dielectric enhancement upon the doping of Co and Co3O4 clusters is discussed. [ABSTRACT FROM AUTHOR]