Showing papers on "Solenoid published in 2018"

Orbital Edelstein Effect as a Condensed-Matter Analog of Solenoids

Abstract: We theoretically study current-induced orbital magnetization in a chiral crystal. This phenomenon is an orbital version of the Edelstein effect. We propose an analogy between the current-induced orbital magnetization and an Ampere field in a solenoid in classical electrodynamics. To quantify this effect, we define a dimensionless parameter from the response coefficients relating a current density with an orbital magnetization. This dimensionless parameter can be regarded as a number of turns within a unit cell when the crystal is regarded as a solenoid, and it represents how “chiral” the crystal is. By focusing on the dimensionless parameter, one can design a band structure that realizes the induction of large orbital magnetization. In particular, a Weyl semimetal with all of the Weyl nodes close to the Fermi energy can have a large value for this dimensionless parameter, which can exceed that of a classical solenoid.

A Digitally Controlled Fully Integrated Voltage Regulator With On-Die Solenoid Inductor With Planar Magnetic Core in 14-nm Tri-Gate CMOS

Abstract: A fully integrated digitally controlled two-phase buck voltage regulator (VR) with on-die solenoid inductors with a planar magnetic core is demonstrated in 14-nm tri-gate CMOS for fine-grained power delivery/management domains of high power density in system-on-chips while enabling ultra-thin (z-height) packages. The VR achieves 1-A/mm2 power density for 400-mA load current with a measured peak efficiency of 84% at 100-MHz switching frequency including a digital PWM with >9 bits (8 ps) of resolution.

Floquet Engineering of Optical Solenoids and Quantized Charge Pumping along Tailored Paths in Two-Dimensional Chern Insulators.

Abstract: The insertion of a local magnetic flux, as the one created by a thin solenoid, plays an important role in gedanken experiments of quantum Hall physics. By combining Floquet engineering of artificial magnetic fields with the ability of single-site addressing in quantum gas microscopes, we propose a scheme for the realization of such local solenoid-type magnetic fields in optical lattices. We show that it can be employed to manipulate and probe elementary excitations of a topological Chern insulator. This includes quantized adiabatic charge pumping along tailored paths inside the bulk, as well as the controlled population of edge modes.

Multiobjective Optimization of a Hollow Plunger Type Solenoid for High Speed On/Off Valve

Abstract: This paper presents the modeling, optimization, and validation of a hollow plunger type solenoid for high speed On/Off valve. In the preliminary design, an accurate equivalent magnetic circuit model of the proposed solenoid is carried out, and the magnetic circuit is arranged in Kirchhoffs voltage law matrix form for the convenience of computer calculation. An iterative method is applied to obtain accurate permeability of the nonlinear magnetic material. To optimize the design parameters, a multiobjective optimization process is developed, and the multiobjective particle swarm optimization method is used to obtain the Pareto front of the desired objectives. An approved solution in Pareto front is selected by analytic hierarchy process and validated by the finite element analysis (FEA) method. A prototype based on the final optimized design is manufactured and tested. The experiment results verified the validation proposed design and optimization process.

The KATRIN superconducting magnets: Overview and first performance results

Abstract: The KATRIN experiment aims for the determination of the effective electron anti-neutrino mass from the tritium beta-decay with an unprecedented sub-eV sensitivity. The strong magnetic fields, designed for up to 6 T, adiabatically guide β-electrons from the source to the detector within a magnetic flux of 191 Tcm2. A chain of ten single solenoid magnets and two larger superconducting magnet systems have been designed, constructed, and installed in the 70-m-long KATRIN beam line. The beam diameter for the magnetic flux varies from 0.064 m to 9 m, depending on the magnetic flux density along the beam line. Two transport and tritium pumping sections are assembled with chicane beam tubes to avoid direct "line-of-sight" molecular beaming effect of gaseous tritium molecules into the next beam sections. The sophisticated beam alignment has been successfully cross-checked by electron sources. In addition, magnet safety systems were developed to protect the complex magnet systems against coil quenches or other system failures. The main functionality of the magnet safety systems has been successfully tested with the two large magnet systems. The complete chain of the magnets was operated for several weeks at 70% of the design fields for the first test measurements with radioactive krypton gas. The stability of the magnetic fields of the source magnets has been shown to be better than 0.01% per month at 70% of the design fields. This paper gives an overview of the KATRIN superconducting magnets and reports on the first performance results of the magnets.

Overview of the Design Status of the Superconducting Magnet System of the CFETR

Abstract: The concept design of the China Fusion Engineering Test Reactor (CFETR) was started in 2012 in two stages. For CFETR-Phase I, the major radius is 5.7 m, the minor radius is 1.6 m, and the magnetic field at the plasma region, BT , is 4–5 T. There were 16 toroidal field coils and six central solenoid coils designed by a Nb3Sn cable-in-conduit conductor (CICC) with the maximum operation current of 64 and 50 kA, respectively. Three types of plasma equilibrium configuration (ITER-like single null, super-X, and snowflake) were designed. The maximum flux provided by the central solenoid is set at 180 V⋅s. However, to get much higher operation parameters such as steady-state operation, particle and heat exhaust, disruption mitigation and avoidance, ELM control, and material damage by high heat flux and neutron, the superconducting magnet system of CFETR-phase II has been updated based on the larger machine with R = 6.7 m−7.0 m, a = 2.0 m, and BT = 6.5–7 T. Such a new design makes over 1-GW fusion power and better plasma performance possible. Hybrid TF coils are designed by a high-performance Nb3Sn conductor, since the maximum magnetic field can reach to 14–15 T. Besides, in order to save the space for the blanket system and get higher flux, a high-temperature superconducting Bi-2212 magnet with better current-carrying performance under high field is supposed to be employed for the CS coils of CFETR-phase II. The Bi-2212 CICC sample has been tested at 4.2 K with a critical current of 26.6 kA under its self-field.

A Digitally Controlled Fully Integrated Voltage Regulator With 3-D-TSV-Based On-Die Solenoid Inductor With a Planar Magnetic Core for 3-D-Stacked Die Applications in 14-nm Tri-Gate CMOS

Abstract: A fully integrated digitally controlled buck voltage regulator, featuring hysteretic and pulse frequency modulation control for maximum light load efficiency, with 3-D through-silicon-via-based on-die solenoid inductor with a planar magnetic core in 14-nm tri-gate CMOS, demonstrates 111 nH/mm2 inductance density and 80% conversion efficiency. The inductance density demonstrated is 20 $\times $ higher than comparable on-die lateral- or spiral-based inductor densities leading to higher light load efficiency.

Exact cancellation of emittance growth due to coupled transverse dynamics in solenoids and rf couplers

Abstract: Weak, rotated magnetic and radio frequency quadrupole fields in electron guns and injectors can couple the beam's horizontal with vertical motion, introduce correlations between otherwise orthogonal transverse momenta, and reduce the beam brightness. This paper discusses two important sources of coupled transverse dynamics common to most electron injectors. The first is quadrupole focusing followed by beam rotation in a solenoid, and the second coupling comes from a skewed high-power rf coupler or cavity port which has a rotated rf quadrupole field. It is shown that a dc quadrupole field can correct for both types of couplings and exactly cancel their emittance growths. The degree of cancellation of the rf skew quadrupole emittance is limited by the electron bunch length. Analytic expressions are derived and compared with emittance simulations and measurements.

Study of Irradiation Effects on Thermal Characteristics for COMET Pion Capture Solenoid

Abstract: A superconducting magnet system for the COMET experiment is now under construction in the Japan Proton Accelerator Research Complex to achieve the most intense negatively charged muon beam in the world. The main part of superconducting magnet system, the Pion Capture Solenoid, will be exposed to the severe irradiation from the production target inside magnets; consequently, superconducting coils will be heated by interactions with the secondary particle. The degradation on thermal conductivity is also expected in these conduction-cooled superconducting coils as the radiation damage can be accumulated in a continuous operation at cryogenic temperature. To investigate the irradiation influence on thermal characteristics of the magnet, a thermal analysis is performed by modeling the three-dimensional structure of the coil with the consideration of irradiation effects. Possible temperature rise in coils with a beam operation is predicted in terms of stability for a continuous operation. In addition, the impact of irradiation effects on the quench protection is discussed in this paper.

DEMO Central Solenoid Design Based on the Use of HTS Sections at Highest Magnetic Field

Abstract: Previous studies indicated that the use of high-temperature superconductors (HTS) in the highest field allows us achieving the required magnetic flux in the central solenoid (CS) of the European DEMO at a reduced outer diameter, which would enable a reduced overall size and cost of DEMO The proposed winding pack design of the CS1 module is based on ten layer-wound subcoils using an HTS, react and wind Nb3Sn, and NbTi conductors in the high, medium, and low field sections, respectively The design utilizes a stainless steel and a superconductor grading leading to different overall current densities in each of the ten subcoils Both, the hoop stress and the vertical loads are taken into consideration for determination of the required stainless steel cross-section in the winding pack The stainless steel grading has been found to have an even more pronounced effect on the overall subcoil current densities than the superconductor grading A preliminary estimation of the space required for the precompression structure is also reported

The KATRIN Superconducting Magnets: Overview and First Performance Results

Abstract: The KATRIN experiment aims for the determination of the effective electron anti-neutrino mass from the tritium beta-decay with an unprecedented sub-eV sensitivity. The strong magnetic fields, designed for up to 6~T, adiabatically guide $\beta$-electrons from the source to the detector within a magnetic flux of 191~Tcm$^2$. A chain of ten single solenoid magnets and two larger superconducting magnet systems have been designed, constructed, and installed in the 70-m-long KATRIN beam line. The beam diameter for the magnetic flux varies from 0.064~m to 9~m, depending on the magnetic flux density along the beam line. Two transport and tritium pumping sections are assembled with chicane beam tubes to avoid direct "line-of-sight" molecular beaming effect of gaseous tritium molecules into the next beam sections. The sophisticated beam alignment has been successfully cross-checked by electron sources. In addition, magnet safety systems were developed to protect the complex magnet systems against coil quenches or other system failures. The main functionality of the magnet safety systems has been successfully tested with the two large magnet systems. The complete chain of the magnets was operated for several weeks at 70$\%$ of the design fields for the first test measurements with radioactive krypton gas. The stability of the magnetic fields of the source magnets has been shown to be better than 0.01$\%$ per month at 70$\%$ of the design fields. This paper gives an overview of the KATRIN superconducting magnets and reports on the first performance results of the magnets.

Effects of neutral distribution and external magnetic field on plasma momentum in electrodeless plasma thrusters

Abstract: The effects of neutral distribution and an external magnetic field on plasma distribution and thruster performance are numerically investigated using a particle-in-cell simulation with Monte Carlo collisions (PIC-MCC) and the direct simulation Monte Carlo (DSMC) method The modeled thruster consists of a quartz tube 1 cm in diameter and 3 cm in length, where a double-turn rf loop antenna is wound at the center of the tube and a solenoid is placed between the loop antenna and the downstream tube exit A xenon propellant is introduced from both the upstream and downstream sides of the thruster, and the flow rates are varied while maintaining the total gas flow rate of 30 μg/s The PIC-MCC calculations have been conducted using the neutral distribution obtained from the DSMC calculations, which were applied with different strengths of the magnetic field The numerical results show that both the downstream gas injection and the external magnetic field with a maximum strength near the thruster exit lead to a s

Overestimation of thermal emittance in solenoid scans due to coupled transverse motion

Abstract: The solenoid scan is a widely used method for the in-situ measurement of the thermal emittance in a photocathode gun. The popularity of this method is due to its simplicity and convenience since all rf photocathode guns are equipped with an emittance compensation solenoid. This paper shows that the solenoid scan measurement overestimates the thermal emittance in the ordinary measurement configuration due to a weak quadrupole field (present in either the rf gun or gun solenoid) followed by a rotation in the solenoid. This coupled transverse dynamics aberration introduces a correlation between the beam's horizontal and vertical motion leading to an increase in the measured 2D transverse emittance, thus the overestimation of the thermal emittance. This effect was systematically studied using both analytic expressions and numerical simulations. These studies were experimentally verified using an L-band 1.6-cell rf photocathode gun with a cesium telluride cathode, which shows a thermal emittance overestimation of 35% with a rms laser spot size of 2.7 mm. The paper concludes by showing that the accuracy of the solenoid scan can be improved by using a quadrupole magnet corrector, consisting of a pair of normal and skew quadrupole magnets.

Design optimization of a solenoid-based electromagnetic soft actuator with permanent magnet core

Abstract: This paper discusses design optimization of an electromagnetic soft actuator composed of two antagonistic solenoids that share a permanent magnet core. First, calculation of the magnetic field and applied force of a solenoid with a permanent magnet plunger is presented as the principal component of this electromagnetic actuator. Design optimization of the coil is discussed considering the geometrical parameters of the coil, including its length, inner and average diameters, number of turns and packing density while the power consumption is bounded. The impact of the actuator size on the resultant force is presented and scaling limitations are discussed. Then, due to the soft nature of the actuator's component, the impact of the cross-section, i.e. lateral deformation of the actuator on the magnetic field at the center of section is investigated as well. The deformation might happen to the actuator due to the load in the transverse direction, especially when the actuator is made of flexible materials.

Solenoid model for visualizing magnetic flux leakage testing of complex defects

Abstract: Magnetic flux leakage (MFL) techniques are widely used for nondestructive testing of ferromagnetic materials. An analytical model of the MFL field is essential for precise determination and reconstruction of defects. In this paper, we proposed a solenoid model based on magnetization mechanisms of the magnetic medium to explain the MFL principle and simulate the MFL field. By introducing the interaction of solenoids and the Jiles–Atherton model, this model can accurately calculate the MFL field of complex defects, particularly the field distortion caused by the coupling of the defect's components. The solenoid model was experimentally demonstrated with a Z-shaped defect in the specimen and proved to be valid for precise calculation of the magneto-optical image. This work reveals the MFL testing principle from the viewpoint of the magnetic medium and thus helps elucidate and eradicate the simulation errors. The more accurate simulation than the common magnetic dipole model facilitates the inverse calculation of defects, even if field distortion is involved.

Thermal-Hydraulic Analysis of the DEMO CS Coil

Abstract: Two alternative designs of the central solenoid (CS) coil were proposed by EPFL-SPC PSI Villigen and CEA Cadarache for the European DEMO Tokamak. The DEMO CS coil consists of five modules, namely CSU3, CSU2, CS1, CSL2, and CSL3, the most demanding of which is the CS1. According to the EPFL-SCP design, the CS1 winding pack is composed of ten subcoils, each consisting of two layers wound with cables of the same kind. Our present work is focused on the thermal-hydraulic analysis of the CS1 cables designed by EPFL-SPC at the normal operating conditions during the whole current cycle. We took into account the realistic magnetic field distribution, heat transfer between neighboring turns, and heat generation due to AC losses. The analysis, performed using the THEA CryoSoft code, was aimed at the assessment of the minimum temperature margin and at verification if the proposed design fulfills the acceptance criterion. For the considered current scenario, the minimum of the temperature margin was observed at the end of the dwell phase. The temperature margin in the subcoils 1–9 was above the 1.5 K criterion, but was slightly too small in the most outer subcoil 10.

Design and Optimization of Electromagnets for Biomedical Experiments With Static Magnetic and ELF Electromagnetic Fields

Abstract: With the expanding usage of various devices, which emit static and extremely low-frequency magnetic fields, increases the number of biomedical reports on their influence as well as demand for suitable experimental exposure systems. Experimental setups range from permanent magnets through Helmholtz coils to solenoids; however, almost all of them provide relatively weak magnetic fields of up to 10 mT. Widespread use of devices such as MR scanners imposes intentional as well as unintentional exposure to stronger fields. A typical solenoid produces stronger although less homogeneous field than the most commonly used experimental equipment composed of sets of coaxial coils. In order to provide scalable, relatively strong, low-varying field within experimental volume that is large enough for in vivo as well as in vitro experiments modified solenoids are considered. Variation of the field was reduced by modifying the shape and size of solenoid's cross section. Modified solenoids were modeled analytically, numerically, and as a prototype. Solenoid geometries were optimized for maximal field performance and minimal power consumption. The optimal modified solenoids scalable to desired sizes of the experimental volume and values of maximal magnetic induction intensities are offered. The suggested solenoid modification method can decrease field variation as much as 10.6 times.

Development of the Helium Inlet and Outlet for the CFETR Central Solenoid Model Coil

Abstract: China fusion engineering test reactor (CFETR) central solenoid model coil (CSMC) made with cable in conduit conductor superconductor had been developed in the Institute of Plasma Physics, Chinese Academy of Sciences. The highest magnetic field of CSMC is 12 T when the running current is 47.65 kA at 4.5 K, and the largest magnetic field change rate is 1.5 T/s. CSMC mainly consists of one Nb 3 Sn inner coil, one Nb 3 Sn outer coil, and three NbTi coils cooled by supercritical He flow. There are totally ten helium inlets and outlets distributed in CSMC. Due to the geometrical discontinuity within the helium inlet and outlet, the helium inlet area is one of the regions, where high stresses can be expected in the CFETR CSMC. This paper describes the structure design, stress analyses, welding R&D of helium inlet and outlet. A local finite element model based on structure design is created to calculate the stress on the helium inlet under electromagnetic load. The welding R&D activities, including welding trials, destructive test, and NDE have been carried out to develop welding technology.

Mechanical performance evaluation of the CFETR central solenoid model coil design

Abstract: The Chinese Fusion Engineering Test Reactor (CFETR) Central Solenoid Model Coil is being fabricated by the Institute of Plasma Physics Chinese Academy of Sciences. The Model Coil is comprised of Nb3Sn and NbTi modules held together by a preload structure. It will operate at 4.5 K to produce a peak field of 12 T at 48 kA. In order to investigate the feasibility and integrity of the Model Coil design before its manufacturing, the mechanical performance has been evaluated for the room temperature preload, 4.5 K stand-by and 48 kA operating conditions. A 1/15 3D detailed model that consists of jackets, insulations, bladders, buffers and preload structure, is constructed and simulated using the coupled structural-thermal-electromagnetic solver of ANSYS. In contrary to a smeared winding pack model, our analysis with the detailed model can directly and precisely simulate the differential thermal contraction effect of the preload structure, jacket and insulations, as well as the electromagnetic load acting on the jacket. The detailed deformation and stress behaviors of the Model Coil are illustrated and discussed. The results indicate that the final design of the CFETR Central Solenoid Model Coil is reasonably conservative and satisfy the design criteria.

Electrically latching rocker arm assembly having built-in OBD functionality

Abstract: An internal combustion engine includes a cam-actuated rocker arm assembly with a solenoid-actuated latch that provides for cylinder deactivation or variable valve actuation. The solenoid is in a position where its inductance varies significantly in relation to the position of a latch pin as it translates between latching and non-latching configurations. A sensor is positioned to monitor a current or a voltage in a circuit that includes the solenoid. The sensor data is analyzed to provide diagnostic information relating to the operation of the rocker arm assembly.

PCB Embedded Bondwire Inductors With Discrete Thin-Film Magnetic Core for Power Supply in Package

Abstract: This paper details the design, assembly, and detailed characterization of printed circuit board (PCB) embedded thin magnetic film inductors for Power Supply in Package applications. Solenoidal inductors were assembled on copper tracks printed on PCB with wire bonds to complete the copper loop. Furthermore, the solenoid inductors have laminated amorphous soft magnetic thin films embedded between the two conductor layers. The devices have chemically thinned Vitrovac films laminated as core material. Three different designs of solenoid inductors with different numbers of turns are assembled and characterized. The assembled PCB inductor measured a highest quality factor of 8.5 for a three-turn device at 10 MHz.

Prediction, experimental results and analysis of the ITER TF insert coil quench propagation tests, using the 4C code

Abstract: The ITER toroidal field insert (TFI) coil is a single-layer Nb3Sn solenoid tested in 2016–2017 at the National Institutes for Quantum and Radiological Science and Technology (former JAEA) in Naka, Japan. The TFI, the last in a series of ITER insert coils, was tested in operating conditions relevant for the actual ITER TF coils, inserting it in the borehole of the central solenoid model coil, which provided the background magnetic field. In this paper, we consider the five quench propagation tests that were performed using one or two inductive heaters (IHs) as drivers; out of these, three used just one IH but with increasing delay times, up to 7.5 s, between the quench detection and the TFI current dump. The results of the 4C code prediction of the quench propagation up to the current dump are presented first, based on simulations performed before the tests. We then describe the experimental results, showing good reproducibility. Finally, we compare the 4C code predictions with the measurements, confirming the 4C code capability to accurately predict the quench propagation, and the evolution of total and local voltages, as well as of the hot spot temperature. To the best of our knowledge, such a predictive validation exercise is performed here for the first time for the quench of a Nb3Sn coil. Discrepancies between prediction and measurement are found in the evolution of the jacket temperatures, in the He pressurization and quench acceleration in the late phase of the transient before the dump, as well as in the early evolution of the inlet and outlet He mass flow rate. Based on the lessons learned in the predictive exercise, the model is then refined to try and improve a posteriori (i.e. in interpretive, as opposed to predictive mode) the agreement between simulation and experiment.

Inductively coupled 30 T magnetic field platform for magnetized high-energy-density plasma studies

Abstract: A pulsed high magnetic field device based on the inductively coupled coil concept [D. H. Barnak et al., Rev. Sci. Instrum. 89, 033501 (2018)] is described. The device can be used for studying magnetized high-energy-density plasma and is capable of producing a pulsed magnetic field of 30 T inside a single-turn coil with an inner diameter of 6.5 mm and a length of 6.3 mm. The magnetic field is created by discharging a high-voltage capacitor through a multi-turn solenoid, which is inductively coupled to a small single-turn coil. The solenoid electric current pulse of tens of kA and a duration of several μs is inductively transformed to hundreds of kA in the single-turn coil, thus enabling a high magnetic field. Unlike directly driven single-turn systems that require a high-current and low-inductive power supply, the inductively coupled system operates using a relatively low-current power supply with very relaxed requirements for its inductance. This arrangement significantly simplifies the design of the power supply and also makes it possible to place the power supply at a significant distance from the coil. In addition, the device is designed to contain possible wire debris, which makes it attractive for debris-sensitive applications.

Helical Solenoid Model of the Electron

Abstract: A new semiclassical model of the electron with helical solenoid geometry is presented. This new model is an extension of both the Parson Ring Model and the Hestenes Zitterbewegung Model. This model interprets the Zitterbewegung as a real motion that generates the electron’s rotation (spin) and its magnetic moment. In this new model, the g-factor appears as a consequence of the electron’s geometry while the quantum of magnetic flux and the quantum Hall resistance are obtained as model parameters. The Helical Solenoid Electron Model necessarily implies that the electron has a toroidal moment, a feature that is not predicted by Quantum Mechanics. The predicted toroidal moment can be tested experimentally to validate or discard this proposed model.

Structural Stress Analysis of the CFETR Central Solenoid Model Coil

Abstract: China Fusion Engineering Test Reactor (CFETR) central solenoid (CS) model coil (CSMC) made with cable-in-conduit conductor superconductor had been developed in the Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, China. The highest field of CSMC is 12 T when the running current is 47.65 kA, and the largest magnetic field change rate is 1.5 T/S. CSMC mainly consists of two Nb3Sn coils and three outer NbTi coils, buffer zone, feeders and joints, and preload supports. The inner diameter of the coil is 1500 mm, and the outer diameter is 3520 mm. Stress analyzes were performed using coupled solver for simultaneous structural, thermal, and electromagnetic analysis. Based on the generalized Hooke’s law, orthotropic smeared property used for the CSMC winding pancake is calculated with one so-called “unit cell” finite-element model of the jacket and insulation. A global finite-element model was created based on the design geometry data to investigate the mechanical property of CFETR CSMC.