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ENN Science and Technology Development Co., Ltd. (ENN) is committed to generating fusion energy in an environmentally friendly and cost-effective manner, which requires abundant aneutronic fuel. Proton-boron (p-11B or p-B) fusion is considered an ideal choice for this purpose. Recent studies have suggested that p-B fusion, although challenging, is feasible based on new cross section data, provided that a hot ion mode and high wall reflection can be achieved to reduce electron radiation loss. The high beta and good confinement of the spherical torus (ST) make it an ideal candidate for p-B fusion. By utilizing the new spherical torus energy confinement scaling law, a reactor with a major radius R 0 = 4 m, central magnetic field B 0 = 6 T, central temperature T i 0 = 150 keV, plasma current I p = 30 MA, and hot ion mode T i / T e = 4 can yield p-B fusion with Q > 10. A roadmap for p-B fusion has been developed, with the next-generation device named EHL-2. EHL stands for ENN He-Long, which literally means "peaceful Chinese Loong." The main target parameters include R 0 ≃ 1.05 m, A ≃ 1.85 , B 0 ≃ 3 T, T i 0 ≃ 30 keV, I p ≃ 3 MA, and T i / T e ≥ 2. The existing ST device EXL-50 was simultaneously upgraded to provide experimental support for the new roadmap, involving the installation and upgrading of the central solenoid, vacuum chamber, and magnetic systems. The construction of the upgraded ST fusion device, EXL-50U, was completed at the end of 2023, and it achieved its first plasma in January 2024. The construction of EHL-2 is estimated to be completed by 2026. [ABSTRACT FROM AUTHOR]

Atomic bandpass filters are used in a variety of applications due to their narrow bandwidths and high transmission at specific frequencies. Predominantly, these filters are in the Faraday (Voigt) geometry, using an applied axial (transverse) magnetic field with respect to the laser propagation direction. Recently, there has been interest in filters realized with arbitrary-angle magnetic fields, which have been made by rotating permanent magnets with respect to the k-vector of the interrogating laser beam. However, the magnetic field angle achievable with this method is limited as field uniformity across the cell decreases as the rotation angle increases. In this work, we propose and demonstrate a new method of generating an arbitrary-angle magnetic field, using a solenoid to produce a small, and easily alterable, axial field, in conjunction with fixed permanent magnets to produce a large transverse field. We directly measure the fields produced by both methods, finding them to be very similar over the length of the vapor cell. We then compare the transmission profiles of filters produced using both methods, again finding excellent agreement. Finally, we demonstrate the sensitivity of the filter profile to changing magnetic field angle (solenoid current), which becomes easier to exploit with the much improved angle control and precision offered by our new design. [ABSTRACT FROM AUTHOR]

Students may calculate the mutual inductance between an infinite solenoid and a surrounding circular loop using an incorrect method that yields the correct answer, causing frustration and confusion. A physical explanation for the agreement of the two methods is provided that is based on the translational symmetry of the solenoid. As a consequence, the conclusion generalizes to infinite uniform solenoids of arbitrary cross section. When students obtain the right answer using an unjustified method, instructors are faced with a grading quandary. Finding himself in that situation, this author asked, "Why?" The resulting paper, which will be enjoyed by instructors of electromagnetism, shares the explanation, involving the mutual inductance of a solenoid and a loop. [ABSTRACT FROM AUTHOR]

The study of soft pneumatic actuator control techniques is an important research topic in soft robotics. However, much of the research has concentrated on upper-level control algorithms, with little attention paid to the bottom-level pneumatic controller. This work aims to develop a simple, low cost, and quick-response pressure controller for soft pneumatic actuators. The controller is designed based on an on/off valve-driven pneumatic supply system, which is high speed, economical, and easy to set up. Using the actual pneumatic properties of a controlled object to estimate the switching time of the valves, the controller avoids complex nonlinear pneumatic computation and can achieve a high control frequency. Experiments demonstrate that the controller performs well in terms of speed and precision, having practical value in the control of soft actuators. [ABSTRACT FROM AUTHOR]

The electromagnetic characteristics of the input cavity with electron beams loaded are measured successfully in an X-band triaxial relativistic klystron amplifier (TKA) with a high frequency electrical probe. To solve the frequency response issue in the X band, a coaxial electrical probe is optimized and inserted obliquely into the input cavity at the designed angle so that the microwaves in the cavity can be sampled and extracted with the required coupling coefficient while the probe does not interfere with the solenoid coil, which is tightly integrated outside the TKA. Besides, the TKA is redesigned as a structure integrally sealed by the solenoid coil, and the secondary sealing induced by probe insertion is implemented on the flange of the solenoid coils rather than on the wall of the TKA, which is conducive to simplifying the coupling structure while maintaining the high vacuum level. The design is examined in a GW level TKA experiment, indicating that microwaves with a power of about 670 MW are generated in the input cavity at a frequency of 8.40 GHz, which is completely consistent with the injected and output microwave frequencies. [ABSTRACT FROM AUTHOR]

In high-temperature superconducting magnets, slow quench propagation of YBa2Cu3O7−δ coils makes the time delay of detection signal and active protection, resulting in the local heat accumulation and further coil degradation accompanied by strong mechanical response. Based on Maxwell's equations, the heat conduction equation, and basic equations of elasticity, we build and theoretically validate a two-dimensional axisymmetric electro-thermal-mechanical model for an insulated pancake coil with real dimensions in this work. Such a model has an important advantage that the simulation domain can be restricted to the coil itself by applying appropriate boundary conditions. The operating current of the coil is ramped up to a maximum and then remains unchanged. By using the model, we perform a systematic study of the quench and stress evolution triggered by various factors in the coil. The results indicate that the quench triggered by a heater is most likely to occur at the inner and outer turns. As the temperature keeps rising, the insulation layer near the heater is most prone to mechanical failure. Whereas if the quench is triggered by a local degradation caused by defects, the electromagnetic stress is dominant in the initial period, and after the initial period, the thermal stress will be dominant. The mechanical failure probably occurs at both ends of the insulation layer close to the degradation layer. In addition, the quench in an axial stack of pancake coils containing a local degradation is also analyzed. It is found that the position where the quench occurs first is mainly determined by the position of the local degradation and the number of the stack's layers. [ABSTRACT FROM AUTHOR]

This paper proposes a drop-on-demand (DOD) system that can produce single droplets of highly repeatable size in the order of 2 mm. This system utilizes an on-the-shelf solenoid injector used in automotive applications. The design methodology is explained along with the necessary measurements and numerical simulations of droplet generation. The invention consists of a solenoid injector that produces monodisperse single or in-series droplets with the help of a developed pulse width modulated signal generator. Mass per injection is measured over a range of supply pressures and injection durations to find the operation window to generate 2 mm droplets. Later, various nozzle geometries are designed and tested by flow simulations. The contracting nozzle is found suitable for generating single droplets, so the design is implemented at the tip of the solenoid injector. The effects of different opening times, pressures, and nozzle's orifice diameters were tested to observe the operating window of the newly designed DOD system and the repeatability of generated droplets by utilizing a coherent circular Hough transform image processing algorithm to measure droplet sizes. The standard deviation of measured diameters is less than 5% of the mean droplet diameter, which is in the range of 1.68–2.07 mm. Next, the voltage and current signals are measured per injection, and exact instants for the initiation and ending for both opening and closing are determined to construct transient mass flow rate functions for flow simulations in which the dependence of droplet formation on the speed of closing is revealed. The numerical and experimental results indicate the repeatability and consistency of the invention. [ABSTRACT FROM AUTHOR]

Liquid handling is a necessary act to deal with liquid samples from scientific labs to industry. However, existing pipetting devices suffer from inaccuracy and low precision when dealing with submicroliter liquids, which significantly affect their applications in low-volume quantitation. In this article, we present an automated liquid pipetting device that can aspirate liquid from microplates and dispense nanoliter droplets with high precision. Liquid aspiration is realized by using a micropump and a solenoid valve, and on-demand nanoliter droplet printing is realized by using a low-cost and interchangeable pipette tip combined with a piezoelectric actuator. Based on the microfluidic printing technology, the volumetric coefficient of variation of the dispensed liquid is less than 2% below 1 µl. A demonstration of concentration dilution for quantitative analysis has been successfully performed using the automated liquid pipetting device, demonstrating its potential in low-volume liquid handling for a wide range of biomedical applications. [ABSTRACT FROM AUTHOR]

The dc and ac flux density vs magnetic field B(H) loops of Epstein electrical strips are measured in an IEC type-A permeameter with a high-quality electrical strip wound double yokes of inside length l0 = 0.2 m and inside height h0 = 0.1 m and in a long solenoid. The relevant demagnetizing and eddy-current effects are analyzed, modeled, and discussed. It is concluded that demagnetizing corrected solenoid measurement developed for determining dc B(H) loops of the material cannot be used for the ac case, owing to complicated eddy-current demagnetizing effects. Permeameter-measured ac B(H) loops with H detected by a flat H-coil of length less than l0/2 touching the strip's middle surface may be considered representative of the actual material because H is very uniform along the strip within 3l0/4. Strips with ac B(H) loops thus determined should be used to calibrate the effective magnetic path length lm of Epstein measurements, where a very nonuniform field is applied to the strips. [ABSTRACT FROM AUTHOR]

A device consisting of an array of coaxial, identical, circular rings behaves like a solenoid when the ratio of its radius and distance between two successive rings is higher than 1. As this ratio decreases, the device significantly deviates from the solenoid behavior. At the same time, a diffraction-like phenomenon for the magnetic field appears when currents of random direction flow through the rings. This phenomenon demonstrates critical behavior. Thus, an extension of the diffraction phenomenon can be done beyond the classical wave diffraction. A possible application of this device could be the diffraction of charged particle beams. [ABSTRACT FROM AUTHOR]

In this paper, we analyzed the influence of a static magnetic field (SMF), generated by a pair of neodymium magnets, on the temperature rise and the specific absorption rate (SAR) of superparamagnetic nanoparticles when exposed to an alternating magnetic field (AMF). Furthermore, we attempted to verify the feasibility of controlling the SAR and steady state temperature increase of the magnetic nanoparticles (MNP) by controlling the magnitude of the applied SMF. Magnetic heating was produced by applying a high-frequency AMF generated by a solenoid coil and an SMF generated by using a pair of magnets; the SMF value could be controlled by varying the separation distance between the magnets. We performed two sets of experiments: in the first, heating was performed using different amplitudes of AMF and SMF. The results showed that while the increase in temperature and SAR was maximum in the absence of an SMF, these values decreased with increasing SMF value, tending to zero as the nanoparticles approached their magnetic saturation state. In the second set of experiments, we used the curve fitting of the experimental data to obtain the required SMF value to achieve two different specific temperatures and SAR values. The measured values of temperature rise and SAR were quite similar to those calculated using the curve-fitted data. Thus, the experimental results confirm the possibility of controlling the heating properties of MNP during magnetic hyperthermia through an applied SMF. [ABSTRACT FROM AUTHOR]

We have developed experimental equipment for observing the Barnett effect, in which mechanical rotation magnetizes an object, at low temperatures. A sample in a rotor is rotated bidirectionally using a temperature-controlled high-pressure gas. The stray field generated from the sample due to the Barnett effect was detected using a fluxgate magnetic sensor with a sensitivity on the order of several picoteslas, even at low temperatures. By replacing the rotor with a solenoid coil, the magnetic susceptibility of the sample was estimated from the stray field to be of the same order of magnitude as that due to the Barnett effect. The Barnett field was estimated using the dipole model. To assess the performance of the setup at low temperatures, measurements were performed on commercial magnetite (Fe3O4) nanogranules. We confirmed the accordance of the g′ factor between the experimental results using the present setup and those of our previous study performed at room temperature. [ABSTRACT FROM AUTHOR]

We present a modified complex-valued Shimizu–Morioka system with a uniformly hyperbolic attractor. We show that the numerically observed attractor in the Poincaré cross section expands three times in the angular direction and strongly contracts in the transversal directions, similar in structure to the Smale–Williams solenoid. This is the first example of a modification of a system with a genuine Lorenz attractor, but manifesting a uniformly hyperbolic attractor instead. We perform numerical tests to show the transversality of tangent subspaces, a pivotal property of uniformly hyperbolic attractors, for both the flow system and its Poincaré map. We also observe that no genuine Lorenz-like attractors appear in the modified system. [ABSTRACT FROM AUTHOR]

In this paper, a comparative investigation of a C-band long-pulse high-efficiency klystron-like relativistic cavity oscillator is carried out by using numerical simulation and practical experiments. It is indicated that owing to the improper configuration of the solenoid, some returning electrons originating from the cathode supporting rod would hit the entrance of the diode and shunt the input electric power. As a result, the startup process of the device is delayed and the saturated output power is decreased as well. In the initial experiment, the output power and the pulse duration are only about 3.2 GW and 78 ns, respectively. To eliminate the influence of the returning electrons, by increasing the turn number of the winding at both ends of the solenoid, the magnetic field at the diode region is enhanced so that the returning electrons could be guided to the shielding bowl in front of the insulator. As the shielding bowl is under the same potential as the cathode, the returning electrons would not shunt the input power. In contrast, after solenoid compensation, the output power of the device is increased to 4.4 GW at a diode voltage of 700 kV and a current of 14 kA, whereas the pulse duration is extended to 96 ns. Also, the corresponding conversion efficiency achieves about 45%. [ABSTRACT FROM AUTHOR]

Presented here is a theory model based on the beam-envelope approach to determine the global behavior of a charged beam propagating through a high intensity linac with a solenoid channel, namely, the orbital evolution of the root-mean-square beam size in the transverse and longitudinal direction. The model is applied to the Gaussian particle distribution, where the motion of an individual particle is governed by linear focusing/defocusing forces in the solenoid channel and RF fields, except for space-charge forces. In this model, highly nonlinear effects that originated from space-charge forces disappear by averaging over the harmonic motions such as the betatron motion and phase motion in the moving direction and the Gaussian distribution. All particles making up a 3D Gaussian bunch obey the same linear equations of motion where all information of nonlinearity in the space-charge forces and the particle distribution are carried in. The theory is validated using Gaussian macro-particle simulation and one of the widely used photonic integrated circuit codes, TraceWin. As an example, the model is applied to the case of an international fusion materials irradiation facility superconducting linac with solenoid guiding and half wave RF acceleration. The results are compared with results obtained by this model and other two approaches. [ABSTRACT FROM AUTHOR]

Solenoid coils with grounded ends positioned on the dielectric window were proposed and numerically studied to reduce the capacitive coupling in conventional inductively coupled plasma (ICP) sources. The capacitive coupling between the plasma and the coils was subsequently suppressed, leading to a significant reduction of the window erosion. To understand the plasma characteristics and the advantages of this configuration, the discharges by the solenoid coil were modeled and compared with a conventional planar coil ICP discharge. The solenoid coil could generate a plasma with higher density than the planar coil under the same absorbed power. The ratio of inductive to capacitive heating power of the solenoid coil was more than one magnitude higher than that of the planar ICP source. The voltage drop on the dielectric window under the solenoid coil was significantly reduced, which was attributed to a potential shielding effect of the grounded end of the radio frequency coil. [ABSTRACT FROM AUTHOR]

In order to make the high-power microwave sources packaged with a permanent magnet more compact and miniaturized, we design a novel compact and lightweight permanent magnet package based on a C-band coaxial transit time oscillator. Before conducting the microwave generation experiment, research on the emission and transmission is carried out. In the beam transmission experiment, when the compact and lightweight permanent magnet is applied, the transmission efficiency in the diode is only 68.1%, while a phenomenon of side emission of electron beams is observed. When a solenoid is used, no side emission occurs. We theoretically analyze this experimental phenomenon and conclude that the radial magnetic field generated by the permanent magnet aggravates the side emission on the surface of a cathode holder. To solve this problem, a novel diode with a gradient cathode holder is proposed. In the beam transmission experiment using the compact and lightweight permanent magnet, this diode can suppress the side emission of electron beams, and the transmission efficiency in the diode is increased to 80.7%. The potential of the diode proved to work efficiently with this permanent magnet package, laying the foundation for the experimental research of microwave generation with this permanent magnet. [ABSTRACT FROM AUTHOR]

A solenoid is a coil wound many times on a cylinder of length greater than its diameter. Solenoids are mainly used as electromagnets, because a magnetic field is formed when current flows through a solenoid. The solenoid described in secondary school and university textbooks is a single-layered solenoid. Further, textbooks and papers focusing on education primarily describe the magnetic fields caused by infinite solenoids. However, most solenoids used in laboratory or daily life are finite solenoids with multiple layers to achieve a strong magnetic field. Examples include solenoid valves, Faraday rotators, and modulators. [ABSTRACT FROM AUTHOR]

A controlled welding arc is an up-and-coming research area for high-efficiency and high-precision wire arc additive manufacturing. This numerical simulation demonstrates that an alternating external cusp magnetic field (ECMF) can compress the arc. This is the result of the reversal of the Lorentz force direction caused by the reversal of the magnetic poles. The simulation results show that the solenoid current directly affects the arc section ellipticity, and the alternating frequency affects the arc contraction. The high-speed photos demonstrate the feasibility of ECMF. [ABSTRACT FROM AUTHOR]

Intense charged particle beams will generally be formed with an initial correlation between their longitudinal properties, including longitudinal variations in current, and their transverse properties, including their radius and divergence. This is due to the competition between the transverse focusing fields in the beam source and the time-varying space charge forces in the beam. In DC electron guns where the current modulation is slow compared to the electron transit time, the nature of these correlations was previously shown to depend on the gun geometry, exhibiting a linear dependence of the beam radius and divergence on the beam current at the gun exit. Here, we extend the previous work to study the transport of beams with such correlation in uniform and periodic solenoid channels. For each transport channel configuration studied, the transverse envelope equation is used to calculate the envelope of 101 beam slices differing in their slice currents, as well as initial radius and divergence (due to their dependence on slice current). For each channel configuration, these calculations are performed 546 times, with each of these iterations considering a different degree of correlation between the radius and divergence, and the slice current. It is found that some degree of correlation between the initial radius and slice current actually aids in beam transport, and the required strength of correlation can be estimated with simple models. Increasing the degree of correlation between the initial divergence and slice current is generally counterproductive, and the degree of sensitivity to such correlations depends on the design of the transport channel. [ABSTRACT FROM AUTHOR]

An intermittent flash evaporation method is proposed. The experimental system of the flashing is realized by an intake or extraction system composed of two solenoid valves and a controller. The feasibility of this flashing method is verified through experiments under conditions of different time ratios of intake to extraction. The mechanism of the intermittent flashing method was studied by analyses of liquid temperature, pressure gradient in the flash chamber, and pressure difference between the flash chamber and the vacuum chamber in flashing processes under different conditions. Results suggested that the amount of steam produced by the flash evaporation with the increase in liquid superheat was more than that of the process with a certain superheat. Periods of intake and the extraction of the intermittent flash evaporation influenced the flashing efficiency significantly. By comparing the results with continuous static flashing, the intermittent flash evaporation is proven capable of improving the flashing efficiency. Appropriate intake and extraction periods promote the flashing process and reduce the amount of air intake in a single flashing cycle. [ABSTRACT FROM AUTHOR]

We present in this Note a numerical study on the dynamic performance of a Dilation X-ray Imager (DIXI). The DIXI including a photoelectron tube (PT) and a magnetic solenoid is modeled in 3D space. The initial parameters of the photoelectrons are sampled with a Monte Carlo code. The trajectories of the photoelectrons are calculated by using the particle-in-cell method, and the transit time spread (TTS) and temporal magnification are analyzed in detail. We have designed a PT with a double-microstrip structure and compared the performance of the double-microstrip PT with the traditional single-microstrip PT. The results show that the sensitivity of the TTS and the temporal magnification to the emission time of the photoelectrons can be significantly reduced by using the double-microstrip PT, resulting in an improvement of the time window. Therefore, the dynamic performance of the DIXI is improved. [ABSTRACT FROM AUTHOR]

The upcoming commissioning of the superconducting (SC) continuous wave Helmholtz linear accelerators first of series cryomodule is going to demand precise alignment of the four internal SC cavities and two SC solenoids. For optimal results, a beam-based alignment method is used to reduce the misalignment of the whole cryomodule, as well as its individual components. A symmetric beam of low transverse emittance is required for this method, which is to be formed by a collimation system. It consists of two separate plates with milled slits, aligned in the horizontal and vertical direction. The collimation system and alignment measurements are proposed, investigated, and realized. The complete setup of this system and its integration into the existing environment at the GSI High Charge State Injector are presented, as well as the results of the recent reference measurements. [ABSTRACT FROM AUTHOR]

We present and compare two high-pressure, high-repetition-rate electric-discharge sources for the generation of supersonic beams of fluorine radicals. The sources are based on dielectric-barrier-discharge (DBD) and plate-discharge units attached to a pulsed solenoid valve. The corrosion-resistant discharge sources were operated with fluorine gas seeded in helium up to backing pressures as high as 30 bars. We employed a (3 + 1) resonance-enhanced multiphoton ionization combined with velocity-map imaging for the optimization, characterization, and comparison of the fluorine beams. Additionally, universal femtosecond-laser-ionization detection was used for the characterization of the discharge sources at experimental repetition rates up to 200 Hz. Our results show that the plate discharge is more efficient in F2 dissociation than the DBD by a factor between 8 and 9, whereas the DBD produces internally colder fluorine radicals. [ABSTRACT FROM AUTHOR]

We investigate the ac magnetic behavior of solution processable, non-stoichiometric zinc ferrite nanocrystals with a series of sizes and zinc concentrations. Nearly monodisperse ZnxFe3-xO4 nanocrystals (x = 0-0.25) with an average size ranging from 7.4 nm to 13.8 nm are synthesized by using a solvothermal method. All the nanocrystals are in a superparamagnetic state at 300 K, which is confirmed by Superconductive Quantum Interference Device magnetometry. Due to the doping of non-magnetic Zn2+ into A site of ferrite, the saturation magnetization of nanocrystals increases as the size and Zn concentration increases. The ac magnetic permeability measurements at radio frequencies reveal that the real part of the magnetic permeability of similarly sized ferrite nanocrystals can be enhanced by almost twofold as the Zn2+ doping level increases from 0 to 0.25. The integration of 12.3 nm Zn0.25Fe2.75O4 nanocrystals into a toroidal inductor and a solenoid inductor prepared via a simple solution cast process yields a higher quality factors than air core inductors with the same geometries up to 5MHz and 9MHz, respectively, which is in the regime of the switching frequencies for the advanced integrated power converters. [ABSTRACT FROM AUTHOR]

The Boltzmann transport equation for phonons is recast directly in terms of the heat-flux by means of iteration followed by truncation at the second order in the spherical harmonic expansion of the distribution function. This procedure displays the heat-flux in an explicitly coordinate-invariant form, and leads to a natural decomposition into two components, namely, the solenoidal component in addition to the usual irrotational component. The solenoidal heat-flux is explicitly shown to arise by applying the heat-flux equation to a right-circular cylinder. These findings are important in the context of phonon resonators that utilize the strong quasi-ballistic thermal transport reported recently in silicon membranes at room temperature. [ABSTRACT FROM AUTHOR]

We developed techniques for H- and E-field sensors utilizing single phase magnetoelectric (ME) hexaferrite slabs in the frequency range of 100 Hz to 10 MHz. Novel circuit designs incorporating both spiral and solenoid coils and single and multi-capacitor banks were developed to probe the physics and properties of ME hexaferrites and explore ME effects for sensor detections. Fundamental measurements of the anisotropic tensor elements of the magneto-electric coupling parameter were performed using these novel techniques. In addition, for H-field sensing experiments we measured sensitivity of about 3000Vm-1/G using solenoid coils and 8000Vm-1/G using spiral coils. For E-field, sensing the sensitivity was 10-4 G/Vm-1 and using single capacitor detector. Sensitivity for multi-capacitor detectors was measured to be in the order of 10-3 G/Vm-1 and frequency dependent exhibiting a maximum value at ~1MHz. Tunability of 0.1%-90% was achieved for tunable inductor applications using both single and multi-capacitors excitation. We believe that significant (~106) improvements in sensitivity and tunability are feasible with simple modifications of the fabrication process. [ABSTRACT FROM AUTHOR]

In this paper, we analyze two types of hysteresis in spin crossover molecular magnets compounds in the framework of the First Order Reversal Curve (FORC) method. The switching between the two stable states in these compounds is accompanied by hysteresis phenomena if the intermolecular interactions are higher than a threshold. We have measured the static thermal hysteresis (TH) and the kinetic light induced thermal hysteresis (LITH) major loops and FORCs for the polycrystalline Fe(II) spin crossover compound [Fe1-xZnx(bbtr)3](ClO4)2 (bbtr=1,4- di(1,2,3-triazol-1-yl)butane), either in a pure state (x=0) or doped with Zn ions (x=0.33) considering different sweeping rates. Here, we use this method not only to infer the domains distribution but also to disentangle between kinetic and static components of the LITH and to estimate the changes in the intermolecular interactions introduced by dopants. We also determined the qualitative relationship between FORC distributions measured for TH and LITH. [ABSTRACT FROM AUTHOR]

A first principles analysis of photoemission is developed to explain the lower than expected rms transverse electron momentum measured using the solenoid scan technique for the body-centered cubic Group Vb (V, Nb, and Ta) and Group VIb (Cr,Mo, andW) metallic photocathodes. The density functional theory based analysis elucidates the fundamental role that the electronic band structure (and its dispersion) plays in determining the emission properties of solid-state photocathodes and includes evaluation of work function anisotropy using a thin-slab method. [ABSTRACT FROM AUTHOR]

Solenoids are frequently used for focusing low-energy beams. In this paper, we show how they can serve as multipurpose diagnostics tools to measure various beam parameters, including energy, emittance, the second moments of the transverse distribution, and the beam position and angle with respect to the solenoid's axis. The energy measurement is based on rotation of the plane of the transverse motion, as opposed to generating dispersion with a dipole. Measurement of the beam trajectory with respect to the solenoid axis is done by analyzing the beam orbit downstream of the solenoid while varying its current. The second moments are calculated by analyzing the beam image on a profile monitor while accounting for the beam rotation caused by the solenoid. We describe in detail the corresponding procedures and the experimental results of these measurements. [ABSTRACT FROM AUTHOR]

We construct an autonomous low-dimensional system of differential equations by replacement of real-valued variables with complex-valued variables in a self-oscillating system with homoclinic loops of a saddle. We provide analytical and numerical indications and argue that the emerging chaotic attractor is a uniformly hyperbolic chaotic attractor of Smale–Williams type. The four-dimensional phase space of the flow consists of two parts: a vicinity of a saddle equilibrium with two pairs of equal eigenvalues where the angular variable undergoes a Bernoulli map, and a region which ensures that the trajectories return to the origin without angular variable changing. The trajectories of the flow approach and leave the vicinity of the saddle equilibrium with the arguments of complex variables undergoing a Bernoulli map on each return. This makes possible the formation of the attractor of a Smale–Williams type in Poincaré cross section. In essence, our model resembles complex amplitude equations governing the dynamics of wave envelops or spatial Fourier modes. We discuss the roughness and generality of our scheme. [ABSTRACT FROM AUTHOR]

The grain boundary phase of Dy-free sintered Nd-Fe-B magnets is modified by using Pr68Cu32 eutectic alloy. The coercivity of the modified magnets reaches 21 kOe, which is the highest value in Dy-free Nd-Fe-B sintered magnets. Microstructural investigations show that a smooth and thick grain boundary layer is formed, and the content of the ferromagnetic elements in the grain boundary layer decreases from 65 at.% to 9 at. %. In addition, the mean grain size (4.5 μm) in the doped sintered magnets is smaller than that (6.5 μm) in the original sintered magnets. The modification in grain boundary and grain size reduces the magnetic interactions among grains and hinders nucleation of reversed magnetic domains, resulting in a coercivity enhancement. [ABSTRACT FROM AUTHOR]

Zeeman deceleration is an experimental technique in which inhomogeneous, time-dependent magnetic fields generated inside an array of solenoid coils are used to manipulate the velocity of a supersonic beam. A 12-stage Zeeman decelerator has been built and characterized using hydrogen atoms as a test system. The instrument has several original features including the possibility to replace each deceleration coil individually. In this article, we give a detailed description of the experimental setup, and illustrate its performance. We demonstrate that the overall acceptance in a Zeeman decelerator can be significantly increased with only minor changes to the setup itself. This is achieved by applying a rather low, anti-parallel magnetic field in one of the solenoid coils that forms a temporally varying quadrupole field, and improves particle confinement in the transverse direction. The results are reproduced by three-dimensional numerical particle trajectory simulations thus allowing for a rigorous analysis of the experimental data. The findings suggest the use of a modified coil configuration to improve transverse focusing during the deceleration process. [ABSTRACT FROM AUTHOR]

Magnetic compensation of gravity allows for ground-based experiments to be carried out under weightless conditions at reasonable cost and without the time limitation of systems such as zero-g airplanes or drop towers. Most of the time classical superconducting solenoids are operated to perform such experiments, which lead to a poor quality of the gravity compensation due to the non-ideal shape of the current and field distribution. In order to improve the quality of simulated microgravity, scientists need to build novel ground-based systems fully dedicated to magnetic levitation. The magnetic design of these levitation apparatuses would be based on theoretical studies of magnetic forces and associated field distributions. The work presented in this paper demonstrates the possibility of producing a magnetic force on paramagnetic and diamagnetic materials that is constant, thus providing a uniform gravity compensation, along a segment in a 3D geometry. These results come from both the decomposition in spherical harmonics of the magnetic field and specific conditions applied on the magnetic force. The magnetic field configuration leads to conical-shape isohomogeneity of the resulting acceleration. As an additional remark to previous works, the impossibility to get a magnetic force varying as 1/r2 is briefly described. [ABSTRACT FROM AUTHOR]

The manipulation of magnetic objects using variable magnetic fields is a growing field of study with a variety of applications. Many magnetic manipulation systems use multiple electromagnets to generate magnetic fields. To control objects in real time, it is necessary to have a computationally efficient method of calculating the field produced by each solenoid anywhere in space. This paper presents a procedure to replace a real cylindrical solenoid of rectangular cross section with infinitely thin shells and rings that generate an equivalent magnetic field. The best approximation for a real solenoid is determined by its physical characteristics. The field produced by these idealized shapes can be calculated expediently using elliptic integrals as can the field gradient and higher-order derivatives. We find that for most real solenoids, the error in the magnetic field approximation is at most 2.5% at a 50% offset and in most cases is much less. [ABSTRACT FROM AUTHOR]