基于超级电容储能方式的秒级磁场

针对高功率微波(HPM)源的引导磁场需求,设计并研制了一套基于超级电容储能方式的秒级脉冲磁场系统。首先简要说明了基于超级电容储能方式磁场系统的基本原理和计算方法,接着详细讨论了超级电容磁场电源设计和对应的螺线管磁场线圈设计,最后通过模拟和实验验证了储能型磁场系统可以输出秒级磁场脉冲,满足高功率微波磁场需求。结果显示,超级电容脉冲磁场输出稳定,磁场位形较好,比较适宜于高功率微波源系统的外加磁场系统。最后分析了设计和仿真过程中的问题并展望了此类技术的应用前景。     

高功率脉冲电源超大电流检测技术研究

随着高功率脉冲电源(Pulse Power Supply)在电磁轨道炮、电磁弹射器及电磁推射装置中的广泛应用,对其产生的脉冲大电流的精确测量显得尤为重要,但目前电流测试领域常用的测试方法由于稳定性不足、量程有限、测量精度不高等缺陷,无法满足具有兆安级放电电流的高功率脉冲电源的测试需求。因此,提出了一种基于罗氏线圈和积分器的超大电流测试技术。首先通过COMSOL有限元分析软件的AC/DC磁场模块建立模型对该电磁环境进行仿真分析,以确定采集系统在该电磁环境中的安全测试距离,并对罗氏线圈和积分器的测试原理做了具体说明,最后搭建硬件平台在实际的试验中证明该方案能够实现对兆安级脉冲大电流的测试,论证了该测试方法的可行性。     

磁场激光治疗装置

德国阿尔法公司将磁场治疗和激光治疗合为一体,制成了一种磁场激光治疗装置。该装置由脉冲发生器、磁场线圈、平板电极和红外激光器组成。脉冲发生器产生各种波形的脉冲,脉冲通过圆形线圈和平板电极产生磁场,作用于人体,达到治疗目的;红外激光器产生红外光束,作用于人体,达到治疗目的。这种治疗装置可通过调节脉冲和频率,获得各种磁场作用,以治疗不同的疾病。治疗时,患者无痛感,无副作用。磁场激光治疗装置@李玲玲     

肖特基二极管中磁场的超快产生

为了发展未来的磁数据存储技术，产生局部的超快磁场是根本。迄今为止，将电流脉冲注入到微型线圈和微型带状线中，以及用高能电子束已经亚纳秒磁场状态的激发。巳提出通过全金属结构的自旋化电流局部注入做磁开关元件的有效方法，而且似乎巳获得验证，在混合型铁磁半导体结构中巳观测到自旋注入。这里介绍在这种混合结构中几种产生局部超快磁场的方案。其基本元件是用聚集约150fs激光脉冲光抽运的肖特基二极管，激光脉冲在半导体-金属结产生电流，转而在平面内产生磁场。这种方案结合了局部电流注入技术和在肖基势垒上产生快速电流。主要特点包括能在样品平面上沿任何方向快速产生局部场，能通过许多磁元件扫描该磁场，以及能以二极管偏压调谐磁场幅度。     

一种非高压条件下的对称脉冲磁场对撞试验研究

本文介绍了激磁波的产生机理，并利用麦克斯韦方程对偶极子磁场传播特性进行了理论分析；设计实现了一种基于对称线圈的脉冲磁场对撞试验装置，对比分析了线圈匝数、作用距离等因素对激励脉冲信号的影响。结果表明，试验条件下对称磁场激励信号幅值近似呈 1/R 规律传播衰减，且在穿透特性上与激磁脉冲波差异较为明显。本文对开展激磁脉冲波的试验研究具有一定借鉴意义。     

超磁致伸缩薄膜耦合特性驱动磁场的设计方法

针对超磁致伸缩薄膜对驱动磁场的要求,设计了一种能产生高均匀度、高强度磁场的赫姆霍茨线圈,并对该线圈的尺寸结构进行了优化设计,同时对磁场轴向和径向的均匀度进行了理论计算和ANSYS仿真.实验验证了该线圈提供的驱动磁场具有很高的均匀度和足够的强度.在此基础上进一步探索性地研究了薄膜内部磁场的动态特性.     

小型化脉冲电流测量线圈的设计

空心罗氏线圈是测量kA级脉冲大电流的常用传感器。随着脉冲电流发生器的小型化发展,集成于脉冲电流发生器的测量线圈也必须进行小型化设计。本文设计了小截面柔性罗氏线圈。在考虑了由线圈绕线引起的漏磁影响后,本文推导了罗氏线圈的输出特性,修正了传统罗氏线圈电磁参数的计算公式。在给定线圈外尺寸的限制条件下,本文推导了罗氏线圈的互感随线圈内径、绕线直径变化的关系式,并据此推出具有最大互感时的设计值。经样品试制与实验测试,罗氏线圈的输出值与理论分析吻合。将该样品用于脉冲电源的脉冲大电流测量,并与标准的Pearson电流探头做对比,比照结果说明研制的罗氏线圈测量准确。     

一种高空核电磁脉冲磁场测量技术

针对高空核电磁脉冲（high altitude electromagnetic pulse，HEMP）试验研究，分析了电小环天线测量原理和频率特性，建立了传感器数值模型，研究了其脉冲接收特性，设计了一种B-dot传感器，研制了一套脉冲磁场测量系统.结果表明:当环面半径小于20 mm，传感器的上限截止频率达到720 MHz以上，标定结果显示测量系统整机的上升时间小于1 ns.应用该系统测试HEMP模拟器的电磁脉冲环境，并与电场测量结果进行了比对和验证，结果与理论相符，该系统具备HEMP模拟器产生的快前沿脉冲磁场的测量能力，同时可推广应用于其他强脉冲磁场测量.     

基于频响函数测量脉冲磁场屏蔽效能的新方法

脉冲磁场屏蔽效能测量是在时域通过对脉冲波形进行测量并按峰值衰减量确定的。从连续波频率响应出发,研究了一种基于频率响应函数构建系统模型,并根据建立的模型计算屏蔽体脉冲磁场屏蔽效能的方法。对该方法的可行性进行了实验分析,结果表明,该方法测量结果与时域测量结果吻合得较好,从而为脉冲磁场屏蔽效能的测量提供了新的测试手段。     

核磁共振陀螺横向补偿磁场优化设计

核磁共振陀螺作为目前世界上体积最小的导航级陀螺,已受到国内外的广泛重视。核磁共振陀螺通过检测磁场中原子核自旋进动频率的改变确定载体角速度,其陀螺精度与磁场的均匀性、稳定性密切相关。导航级核磁共振陀螺需要飞特级磁场环境,高效磁屏蔽一般仅能完成5～6个数量级的磁抑制,还需进行主动磁补偿。该文从核磁共振陀螺磁场分布的理论分析出发,通过数学计算和计算机仿真,分析和研究了横向磁补偿系统的磁场分布,并对横向磁补偿线圈进行了优化设计。设计的核磁共振陀螺横向磁补偿系统磁场均匀性较优化前提高约13倍,满足了核磁共振陀螺的使用需求。该工作为核磁共振陀螺仪设计和制造提供了一定的理论依据和参考价值。     

长脉冲相对论速调管放大器杂频振荡的分析与抑制

分析了S波段长脉冲相对论速调管放大器(RKA)输出微波杂频振荡和功率波形包络振荡的主要根源,采用粒子模拟程序对RKA电子束尺寸和阻抗、群聚距离、输出腔有载Q值、引导磁场、注入微波等参数的调节,有效抑制了杂频振荡. 根据分析结果开展了相应的实验研究,得到了较好的实验结果,输出微波由300MW提高到540MW,脉宽由50ns提高到120ns,辐射微波重复频率20Hz,束波转换效率30％,杂频振荡得到了有效抑制.     

Superconducting rectifier fluxpump for magnet system of the CMD-2detector

A superconducting rectifier fluxpump has been used for the dc power supply of the magnet system of the CMD-2 detector on the VEPP-2M collider at the Budker Institute of Nuclear Physics in Russia since 1989. The fluxpump provides a complete pumping cycle: charging the magnet system, stabilization of the magnetic field, and discharging. The fluxpump consists of an air-core current step-up superconducting transformer and two groups of thermally controlled superconducting switches arranged as a fullwave rectifier. Critical output current during the test was 5.4 kA. The accuracy of the field stabilization provided by the fluxpump is 2.5·10^-5. The fluxpump has exhibited reliable and safe operation during its entire history of use     

X波段低磁场相对论返波管振荡器实验研究

基于现有永磁磁体的参数,并结合高功率微波器件的优点,设计了一个X 波段低磁场相对论返波管振荡器,当引导磁场强度为0. 48T、二极管束压和束流分别为530 kV 和7. 0 kA 时,通过粒子模拟软件得到频率9. 42 GHz、功率1. 11GW 的模拟微波输出,器件束波转换效率30%。在强流电子束加速器平台上进行实验研究,当二极管电压500kV、电流6. 2kA、引导磁场强度0. 46T 时,得到频率为9. 40GHz、功率为900MW、脉宽为32ns 的微波输出。该实验结果为低磁场器件实现高功率、高效率微波输出及永磁包装打下了良好的基础。     

A superconducting magnet system for free-electron cyclotron maser

A superconducting magnet system for free-electron cyclotron maser is developed. This system includes a main superconducting magnet, a gradient superconducting magnet, a normal magnet, a cryostat and some accessories. The designed magnet system has the advantages of having a small size, high stable magnetic field and suitable field profile. It is very suitable for a 4mm wavelength free-electron cyclotron maser. The design and some experimental results are given.     

低磁场S波段相对论返波振荡器模拟与实验

为实现高功率微波(HPM)系统的小型化,设计一个S波段较低磁场相对论返波管(RBWO)振荡器.针对低磁场特点,分析慢波结构、引导磁场、束压、束流等对输出微波的影响,通过模拟软件(PIC)优化结构.以此设计引导磁场为0.24 T,电子束束压为725 kV,束流为6 kA,频率为3.53 GHz,输出微波功率为1.22 G...     

基于Ansoft汽车永磁电机磁场有限元分析

针对Ansoft Maxwell软件的电磁仿真方法是否有效,分别采用Ansoft Maxwell和Simplorer软件对磁场和电路进行仿真的方法。分析了永磁同步电机的结构,建立永磁同步电机的电-磁场理论模型和电磁损耗模型,用电磁仿真软件进行仿真。通过电机性能实验台测试永磁同步电机的关键输出特性,并与仿真结果进行对比分析。结果表明,参数误差均＜5%,验证了电磁仿真的有效性。     

Development of a Conduction-Cooled HTS SMES

A 35-kJ/7-kW conduction-cooled high-temperature superconductor (HTS) superconducting magnetic energy storage (SMES) is developed. This paper presents the configuration of the HTS SMES and a part of important test results. The magnet of the SMES is a solenoid-type coil made of Bi-2223/Ag tapes, and cooled to about 20 K by conduction-cooled method. The SMES is assembled in the Electric Power System Dynamic Simulation Laboratory, Huazhong University of Science and Technology. A series of tests are successfully carried out to evaluate the performance of the SMES, including the current-carrying ability of the magnet, the active and reactive power exchange capability between the SMES and a simulated power system, as well as the power-compensating effect of the SMES to the simulated power system after short-circuit fault, etc.     

New design concept of the magnet system generating the high pulsed field in combination with the bias field of the superconducting magnet

A new design concept of the axisymmetric magnet system generating the very high pulsed magnetic field which is superimposed on the bias magnetic field of the superconducting magnet is presented. The pulsed magnet consists of two coaxial coils which are wound in opposite directions. The geometry of both pulsed coils, i.e. the working (inner) one and the compensating (outer) one is designed in such a way that the mutual coupling between the small pulsed magnet and the outer superconducting magnet is practically zero. This configuration prevents the rise of the high induced voltage on the current leads of the superconducting magnet when the pulsed magnet is being energised, hence resulting naturally in protection of the system (superconducting magnet and the current source) against possible damage. Further, it is predicted that the stray field of the pulsed magnet, which gives rise e.g. to the eddy currents in the winding of the superconducting magnet, is considerably decreased. The simple theory enabling the design of the geometry of the compensating pulsed coil is derived. The advantages of this new concept are demonstrated on the results of the theoretical analysis using, as an example, one of the pulsed coils that were designed and fabricated in the Clarendon Laboratory, in connection with the Oxford Instrument superconducting magnet (Clarendon hybrid outer) which can generate a steady magnetic field up to 10 T in a room temperature working space with a diameter of 240 mm.     

MWECR CVD系统中磁场梯度对a-Si∶H薄膜沉积速率的影响

为了定量地得到磁场梯度对a-Si∶H薄膜沉积速率的影响,对单磁场线圈分散场MWECR CVD系统等离子体室和沉积室中用三种方法得到的磁场形貌进行了研究.通过洛伦兹拟合的方法定量地得到了这些磁场形貌的磁场梯度.结果表明,样品台下面放置钐钴永磁体并使磁场线圈电流为137.7A时其衬底附近磁场梯度值最大,样品台下面无钐钴永磁时,磁场线圈电流分别为137.7A和115.2A的磁场梯度值依次为次之和最小.制备a-Si∶H薄膜时,在衬底附近具有高的磁场梯度值可以得到高的沉积速率.通过红外吸收谱技术分析,虽然样品台下面放置钐钴永磁体并使磁场线圈电流为137.7A下能得到最大的沉积速率,但是沿样品台半径方向沉积速率呈现很明显的不均匀分布.     

Superconducting magnet system of the CMD-2 detector

This paper describes the superconducting magnet system of the CMD-2 detector. The magnetic field is provided by the main and two compensating superconducting solenoids. The unique features of this system are the solenoids protection method utilizing a distributed resistance along the coil and the power supply being a fluxpump type. The main solenoid produces a field up to 1.2 T in a volume of φ 0.71 m×0.9 m. Its radiation thickness and E/M ratio are 0.38 X₀ and 5 kJ/kg, respectively. NbTi/Cu superconducting cables without any insulation and an aluminum stabilizer were used for the design of solenoid coils. The superconducting cable was wound in a stainless-steel bobbin and soldered by a PbSn alloy. The cooling bath provides a temperature of 4.2 K in the system. The superconducting magnet system of the CMD-2 detector was manufactured and tested in 1989