共查询到19条相似文献,搜索用时 125 毫秒
1.
针对目前超宽谱短脉冲电场测量传感器标定问题,研制了以镜面单锥结构为核心的超宽谱短脉冲电场标准装置,用于超宽谱短脉冲测量传感器校准。该标准装置内部的电场分布可基于结构参数、麦克斯韦方程及激励脉冲解析给出。通过理论分析和数值分析验证了该技术路线的可行性。完成了标准装置的机械工艺设计及加工,并进行了测试。测试结果表明:研制的标准装置在馈电处电压反射系数小于4%;内部电场波形与激励波形一致,且电场幅度分布与严格理论结果偏差小于6%。 相似文献
2.
3.
对一种短偶极子类小型短电磁脉冲传感器进行了研究,分析了传感器电容、有效面积与结构参数之间的解析关系,给出了传感器的工作原理。根据应用需求设计了不同带宽的该类传感器,并对其波形保真性和有效面积进行了数值分析,仿真结果表明:经传感器接收并还原所得场波形与激励电场波形几乎完全重合,传感器有效面积与理论分析结果偏差小于1%。对传感器的焊接、定位和对轴等制作工艺进行了研究,完成了传感器样品的制作。利用单锥TEM室对传感器的波形保真性和有效面积进行了实验测试,测试结果表明:设计制作的传感器样品可以很好地恢复待测脉冲电场的波形和幅度,两支传感器样品的有效面积实测结果与解析计算结果较为一致,偏差分别小于4%和7%。 相似文献
4.
弓网离线放电电磁辐射具有瞬态、宽频带的特性,可使用D-dot传感器对其进行时域瞬态电场测量,但在对传感器所测微分信号积分还原时,存在信号恢复失真问题严重。搭建了包含脉冲电场发生装置和测量装置的瞬态电场时域波形还原系统,开展了基于D-dot传感器的去直流、数值积分、消除趋势项以及系统辨识低频补偿在内的瞬态电场时域波形测试方法的研究,利用该方法测试了不同电压下弓网离线放电电磁辐射的电场时域波形。理论与实验结果表明:本文所提出的方法能准确、稳定地还原弓网离线放电所辐射瞬态电场的原始时域波形,还原信号与实测微分信号的主要频率分量均在7.5 MHz,二者的相关系数达到93%以上。 相似文献
5.
考虑到辐射波电磁脉冲模拟器笼形天线尺寸过大、在单个微机上计算其辐射特性的时间过长及内存受限制,使用基于消息传递接口(MPI)平台的用于同轴线馈电的时域有限差分并行算法,并结合天线理论模拟分析了同轴线馈电的辐射波电磁脉冲模拟器双锥笼形天线在双指数脉冲电压激励下的脉冲辐射特性。并行时域有限差分计算时,整个时域有限差分计算区域的网格总数约为20亿。由计算结果分析可知:当锥半径大于3.5 m后,笼形天线的半径大小对电场的上升沿和峰值的影响不大;对地面上方0.5 m处的几个测试时,其上升沿、半高宽及脉冲峰值受地面反射及地面损耗的影响比较大,而对于地面上方6 m处的几个测试点,除半高宽外,几个测试点的辐射场脉冲峰值及上升沿受地面影响较小;离地面越近的点,峰值减小得越快。 相似文献
6.
7.
8.
为了开展大口径天线短脉冲微波辐射特性研究,建立了一套大口径天线微波短脉冲特性测试系统。该系统可产生快上升沿、脉冲可调(脉宽最短可到0.5 ns)的微波激励脉冲、接收动态范围大于52 dB。利用该测试系统进行实验,获得了不同微波激励脉冲宽度条件下,天线方向图和辐射场波形脉冲宽度变化曲线。测试结果表明:在天线远场距离处,改变微波激励脉冲宽度,对天线主轴辐射场波形基本无影响;而在偏离主轴处,辐射场波形会出现不同程度的脉冲展宽及幅值减小等波形畸变现象,偏离主轴角度越大,微波激励脉冲宽度越小,畸变越明显。 相似文献
9.
介绍了短脉冲应用中磁芯的选取,设计了一台两路并联馈电的单模块直线型脉冲变压器驱动源(LTD)装置。在低压情况下测试了装置对不同脉宽信号的响应特性,在此基础上利用一级脉冲形成网络提供的输出阻抗约5 Ω,脉宽约3 μs的近似方波信号对装置进行了高压实验,得到了匹配负载情况下LTD次级上的输出电压波形,和脉冲形成网络的输出波形得到了很好的吻合。建立了相应的LTD电路模型,利用Laplace变换推导了模型对有限上升前沿脉冲的响应,证明了励磁电感偏小是造成实验中LTD装置输出电压幅值明显低于充电电压的主要原因,提出了改进方法并进行了实验验证。 相似文献
10.
在脉冲电路设计中,需要根据实际应用的波形要求和负载特性选择、设计其电路构型。工程设计中常用的时域波形叠加和参数扫描等波形构型设计方法存在较大局限性,难以形成对脉冲波形构型的物理本质、脉冲电路结构对负载的适应性等方面的系统认识。从分析影响脉冲波形构型的基本要素入手,从时域和频域角度对脉冲波形构型及其电路实现方法进行系统的分析和归纳,给出时域和频域的电路构型设计方法及相应的电路参数解算方法,使设计人员可采用解析分析方法判断电路中元器件参数的调整方向,同时推动电路设计创新。 相似文献
11.
The diffraction of temporally Gaussian shaped light pulses is theoretically studied by means of the aberrationless approach, a theoretical technique previously used for spatially bounded beams of unlimited time extension and which is extended here to time domain. We consider linear interfaces, that is, we assume that the spectral components of the vector field in the diffracted pulse are linearly related with the spectral components of the vector field in the incident pulse. In our analysis pulse deformations are described in terms of the following effects: time delay, focal displacement, waist modification and change in propagation velocity. Expressions for these effects, the time domain analogues of those already reported in the spatial domain, are given and compared with those obtained using the stationary phase method. The theory is used to calculate deformations of a short light pulse at a flat interface near conditions of total internal reflection. 相似文献
12.
对冲击波参数的测量开发了两种光纤探针,以满足强电磁环境和冲击压力较低的情况。一种是冲击自发光光纤探针,另一种是闪光隙光纤探针。这两种光纤探针分别利用融凝石英在受到冲击压缩时发光和氩气(或空气)隙在受到压缩时会产生很强的光辐射的机理研制而成的。自发光光纤探针在大于70 GPa冲击压力下,其信号上升时间在1~3 ns之间;闪光隙光纤探针在10~30 GPa的冲击压力下,其信号上升时间稳定在2~7 ns之间。 相似文献
13.
环形正负电子对撞机(CEPC)是一台周长100 km,最高能量为120 GeV的双环对撞机。为了满足不同能量粒子从增强器注入到对撞环,针对W和Z能量模式设计了对撞环离轴注入系统,用于实现束流的累积。为了提高注入效率,兼容不同注入能量,不同束流填充模式,同时尽可能减少注入过程中冲击磁铁对其它束团的扰动,要求对撞环离轴注入冲击磁铁系统是一个上升时间和下降时间小于200 ns,脉冲底宽调节范围为440~2420 ns的梯形波脉冲放电系统。和常见的集中参数型冲击磁铁相比,分布参数型冲击磁铁具有更优越的动态响应特性,适合产生一个前沿更加陡峭、波形更为理想的梯形波脉冲。根据CEPC的束流注入物理需求,完成了一台分布参数型冲击磁铁的物理设计和结构设计,并采用了PSpice和Opera程序进行模拟仿真。设计结果表明:冲击磁铁由26级LC单元结构叠装而成,磁铁总长为1018 mm,磁有效长度为942 mm;在[-20,20] mm磁铁孔径内,磁场强度为0.042 1 T,磁场均匀性优于±0.2%;冲击磁铁系统总上升时间(10%~90%)为193 ns,下降时间(90%~10%)为191 ns。理论分析、... 相似文献
14.
A scattering scheme to probe the time evolution of femtosecond pulses of a soft X‐ray free‐electron laser (FEL) in a multilayer structure is presented. The response of periodic multilayers (MLs) with low and high absorption and various numbers of bi‐layers to a pulse train of Gaussian‐shaped sub‐pulses is calculated. During the passage of the incident pulse the interaction length increases and the scattering profile changes as a function of the spatial position of the pulse within the sample. Owing to stretching of the reflected pulse compared with the incident pulse, the time‐dependent scattering evolution in the ML can be visualized along a spatial coordinate of a position‐sensitive detector. Using a scattering geometry where the mean energy of the incident pulse train is slightly detuned from the energy of maximum reflectivity at the first‐order peak, the response of the ML shows an oscillator behaviour along this spatial coordinate at the detector. For a FEL wavelength of 6.4 nm this effect is promising for MLs with low absorption, such as La/C for example. On the other hand, the oscillations will not be present for MLs with high absorption. Therefore a low‐absorbing ML is a sensitive tool for studying the possible change of sample absorption caused by femtosecond‐pulse interaction with matter. 相似文献
15.
16.
We demonstrate a passively Q-switched Nd:LuVO4 laser at 916 nm by using a Nd, Cr:YAG crystal as the saturable absorber. As we know, it is the first time to realize the laser with a simple linear resonator. When the incident pump power increased from 14.6 W to 23.7 W, the pulse width of the Q-switched laser decreased from 24 ns to 21 ns. The pulse width was insensitive to the incident pump power in the experiment. The average output power of 288 mW with repetition rate of 39 kHz was obtained at an incident pump power of 22.5 W, with the optical-to-optical efficiency and slope efficiency 1.3% and 3.6%, respectively. 相似文献
17.
Measurements have been conducted to determine the turn-on times of a triggered vacuum gap as a function of main gap voltage and trigger and main gap polarities. The triggered vacuum gap consisted of a pair of molybdenum electrodes mounted in a low-inductance (20 nH) stainless-steel chamber. Triggering was accomplished by supplying a 10-kV pulse from a charged 12.5-? cable circuit to a tungsten trigger pin protruding through one electrode. The main gap voltage was supplied by a 4-? charged cable circuit. Minimum wait times (the time from application of the trigger pulse to the beginning of main gap voltage coliapse) of 50 ns were observed when a negative pulse was applied to the trigger located in the cathode. A minimum value of voltage collapse time of 10 ns was observed when a positive pulse was applied to the anode located trigger. The switch could be triggered for all main gap voltages in the range 50 V-75 kV, with minimum delay times occurring at 500 V. 相似文献
18.
By simultaneously using both an acoustic-optic (AO) modulator and a V3+:YAG saturable absorber in the cavity, for the first time to our knowledge, a diode-pumped doubly Q-switched Nd:GdVO 4 laser has been realized. The dependence of pulse width, pulse energy and peak power on the incident pump power at determinate pulse repetition rate are measured. Under the absorbed pump power of 8.59 W, the pulse temporal profile of the AO-switching with the pulse duration of 14.5 ns, the double Q-switching with pulse duration of 7.6 ns at 10 kHz, and the passive Q-switching with pulse duration of 22.3 ns are obtained. The pulse duration is obviously compressed in contrast to the purely actively AO Q-switched laser or the purely passively Q-switched laser with V3+:YAG. 相似文献