四级串联共用腔体MA级FLTD的设计与仿真

摘要

目前MA级快脉冲直线变压器驱动源(FLTD)模块一般引入2~4路快前沿(约20ns)高幅值(100kV)电脉冲触发,百TW级数十MA的FLTD驱动源含有数千个模块,其触发系统非常庞大,并且要求触发脉冲按照精确时序到达各级串联模块,以便实现与次级行波同步的感应电压高效叠加,触发系统成为大型FLTD驱动源的瓶颈之一.在之前提出的一种利用一路外触发脉冲实现数十模块串联FLTD与次级行波同步的感应电压高效叠加触发方式基础上,设计了4级串联共用腔体的MA级FLTD模块组,每级共24支路,其中1个用作触发支路,主放电支路由2只100nF双端引出电极电容器和1只GW级气体开关组成;建立了16级串联、次级为水线的单路FLTD电路模型,数值仿真研究了支路开关自放电、触发支路开关闭合时序与分散性,以及次级传输线阻抗对驱动源的影响.%Fast Linear Transformer Drivers (FLTDs)can directly produce high-power pulse with the rise time 70-200 ns,which are based on magnetic coupling by many bricks connected in parallel in a circular annulus to output MA current and tens of cavities connected in series to output MV voltage.FLTDs are regarded as the next petawatt drivers for Z-pinch by international scientific community.At present,mega-ampere scale FLTD cavities need two or four triggering pulses with 100 kV and rise time of 25 ns in general,so the petawatt FLTD drivers consist of several thousand cavities require ten thousands of the triggering pul-ses and should be arrived the different position cavities at accurate sequences in order to realize the secondary pulses to superpose inductively and efficiently,which is the bottleneck of the FLTD development.The paper presents a creative FLTD module with four stages in series sharing induction cavity shell and a novel trigger method achieving nearly ideal IVA triggering sequence for each FLTD module.The FLTD module with mega-ampere current output consisting of 1 6-cavities in series is designed.The cir-cuit model of the new structure of 1 6-stage FLTD is developed.The influences of the switches'prefire of main bricks,the trigge-ring brick switches'closing sequences and jitter,and the secondary transmission line impedances are simulated based on the cir-cuit model.