脉冲激光器大电流窄脉冲驱动设计

介绍了利用金属氧化物场效应管产生大电流窄脉冲来驱动激光二极管的原理,推导出驱动金属氧化物场效应管峰值驱动电流的计算公式和开通时间的估算公式,通过仿真总结出影响驱动电源脉冲电流的脉宽、幅度和振荡的主要因素,理论和仿真结果表明,器件的寄生电感、电路走线电感和负载寄生电感对电流影响较大。实验结果显示,在供电高压为200 V时,金属氧化物场效应管开通时间为2 ns;激光二极管驱动电流上升时间小于10 ns,脉宽为15~100 ns,幅度为0~50 A连续可调,频率为0~50 kHz。     

加速器中内置式预脉冲抑制电感的研制

 介绍了预脉冲抑制电感值的选取、大体积电感值的计算、电感在传输线内筒中的绝缘设计和主脉冲在电感上的传输时间以及等效阻抗。根据对电感值与传输线、输出线电压和二极管电流之间关系的数值模拟,预脉冲抑制电感应取值5 μH,并通过实验给出了屏蔽筒中大型电感的计算方法。根据对电感管与传输线内筒之间以及电感匝间电场强度的分析和数值模拟,确定了电感长度630 mm、外径1 160 mm和管径102 mm。通过对电感与传输线内筒之间构成的带绕螺旋传输线等效PSpcie的模拟计算,得到了电感传输线支路上的单次传输时间为349 ns,大于主脉冲的宽度;在主脉冲期间,带绕传输线的阻抗大于25 Ω,也远大于传输线的阻抗。通过内置式预脉冲抑制电感已向水介质同轴线中的气体开关引入了触发高压和工作气体。     

EDGE REYNOLDS STRESS STRUCTURE OF LOWER HYBRID WAVE INJECTION IN THE HL—1M PLASMA

The radial profiles of electrostatic Reynolds stress,plasma poloidal rotations,radial and poloidal electric fields have been measured in the plasma boundary region on the HL-1M tokamak using a multi-array of Mach/Langmuir probes.During experiments of lower hybrid wave current drive,the variations in LHW drive power xill cause changes in the edge electric field,poloidal rotation veloity and Reynolds stress.The results indicate that sheared poloidal flow can be generated in the edge plasma due to radially varied Reynolds stress.     

爆磁压缩装置经组合功率调节系统产生高电压的实验研究

 介绍了以爆磁压缩装置为脉冲功率能源,经变压器和爆炸金属丝断路开关组合功率调节系统,在电阻负载上产生高电压的实验研究。实验结果为：在100W 水电阻负载两端得到了约800kV的高电压脉冲,脉宽约100ns。此项工作拓宽了爆磁压缩装置的应用范围。     

Current clamp at zero level in JT-60U current hole plasmas

It is found that no current is driven in a central region of a tokamak plasma once the central current density becomes nearly zero ("current hole"), in spite of high electric conductivity, at the current drive by a toroidal electric field and a radio-frequency wave in experiments on the JT-60U tokamak. This is a new, stiff, self-organized structure of a magnetic field in an axisymmetric toroidal plasma.     

The motion of crystal electrons in an electric field

Crystal electrons in an electric field are described by Houston-wave functions. Their group velocity is averaged over the relaxation timeτ. This yields the current to be ohmic in weak fields and to be inversely proportional to electric fields which are strong enough to drive the electrons through the whole Brillouin-zone in a timeT<τ.     

光导开关级联Blumlein型脉冲网络设计

为了驱动重复频率运行高阻抗X光管,设计了基于光导开关的级联Blumlein型脉冲形成网络。采用数值模拟方法优化网络参数,从网络充电电压一致性、输出脉冲波形畸变、电压叠加效率、负载预脉冲幅值出发确定了充电电感和支撑电感设计原则。实验表明:光导开关工作场强23.2 kV/cm,激光触发能量3.5 mJ时,阻抗约15.6 的Blumlein型脉冲形成网络电压转换效率为0.71,2级级联网络电压叠加效率0.96。     

Current drive by an HF electromagnetic wave in a magnetized plasma

The problem of current drive by an HF wave is analyzed in a one-particle model of a magnetized plasma. A general expression for the current drive is derived by an averaging method in the nonrelativistic case, in second order in the expansion parameter. The presence of a constant and strong magnetic field, the presence of a constant electric field, and the dynamic friction effect are all taken into account. For a monochromatic wave with an amplitude which varies slowly in time and space, expressions for the current drive are derived in closed form. The mechanism for the current drive is analyzed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 87–91, March, 1989.     

异型磁体/铁电复合材料中的电致变磁导及电致变阻抗效应

利用应力变磁导与电致伸缩效应的乘积效应,设计和制备了一种新型的异型磁体/铁电复合材料,并研究了该材料的电磁耦合特性.在5 kV/cm的恒定电场下,观察到接近40%的电致变磁导（电感）及相应的电致变阻抗效应存在于一个较宽的频域（50—1×10⁵Hz）上.该电致变磁导（电感）及电致变阻抗显示了铁磁弛豫和铁电弛豫的联合效应.研究认为,该异型复合材料所显示的所有电磁耦合行为均可归因于电场诱导的材料中磁体内部应力场的变化. 关键词： 电磁耦合 异型复合材料 应力变磁导 电致伸缩     

A Polarization-Converted Coupler for the Fast-Wave Current Drive

This paper proposes a new type of waveguide coupler for the fast-wave current drive in large tokamaks. The coupler has a narrow width to be arrayed in the toroidal direction for the phasing, and radiates the electric field perpendicular to the main toroidal magnetic field through the Faraday shield. The coupler consists of tuned posts or ridges in the cutoff cavity and triangle-shaped waveguides inside the rectangular waveguide. Model experiments verify its basic characteristics, and theoretical estimates indicate that the polarization-converted coupler has the power capability in the range of megawatts.     

HL-1M托卡马克边缘参数和雷诺胁强的径向分布

利用多组马赫/郎缪尔探针测量了HL-1M装置刮离层和边缘静电雷诺胁强，等离子体极向旋转，径向和极向电场的径向分布，在低杂波电流驱动，超声分子束注入，多发弹丸注入和中性束注入实验中，给出了雷诺胁强和极向流的关系。结果表明，由于雷诺胁强的径向变化，托卡马克等离子体可以自发地产生剪切极向流。     

低混杂波电流驱升与等离子体平衡

本文研究了低混杂波电流驱动与等离子体平衡问题．考虑了感应电场，得到了自洽方程组，并把它应用于托卡马克工程实验混合堆电流驱升阶段的某一时刻，研究了该时刻低混杂波电流驱动与ＭＨＤ平衡。计算中采用了一个较宽的波谱，得到了电流与安全因子ｑ的分布。     

Magnetic Vortex Tubes in Astrophysics

The viscous forces on electrons and ions in a differentially rotating plasma drive an azimuthal current density j?, with axial magnetic field Bz which is shown to be proportional to plasma vorticity. Field strengths in agreement with those observed for both stars and galaxies are obtained, assuming that reactive forces prevent radial drifts of electrons or ions. Hierarchical vorticity is required in order to reconcile the small-scale length required for field changes with the large-scale length of observed fields. A vortex tube with magnetic field (magnetic vortex tube-MVT) becomes the basic entity for the origin of magnetic fields. Twisting of field lines by differential rotation causes (1?,Bz,) ?(jz, B?,). When jzB?, > j?, Bz the MVT suffers magnetic pinch, and the axial current in the pinch flows through a cylindrical sheath with a radial electric field due to plasma polarization. An instability of drift velocity denudes a length R of the current channel of free charges, and the inductively maintained current then requires a displacement current in R and hence a growing axial electric field Ez, Ez is limited by transfer of the energy in B?, to Ez, and thereafter the energy oscillates between the fields. On the stellar scale, evidence for polar MVT's comes from young stars with bipolar outflows of gas and jets. It is argued that end-on viewing of polar MVT's accounts for the kilogauss fields of Ap stars and the 1-100-MG fields of magnetic white dwarfs.     

轨道式多间隙气体开关设计与性能测试

针对直线脉冲变压器对低电感、低抖动气体开关的研制需要,采用垂直布放的平板轨道电极,组成具有通视结构的水平间隙,设计了一种多间隙轨道式气体开关。利用Meek击穿判据计算了单间隙自击穿电压,实测了4个单间隙的自击穿电压及其相对标准偏差,并根据单间隙自击穿电压,利用概率分析方法预测了多间隙开关自击穿电压,计算值与实测结果一致。研究表明:开关电感最大约109 nH,自击穿电压相对标准偏差为1.5%,在60 kV触发电压和48%~74%欠压比下,开关抖动0.9~2.6 ns。与圆环形电极的多间隙气体开关相比,多间隙轨道式气体开关自击穿电压更稳定,也更容易触发。     

低混杂波电流驱动中原副边回路相互作用

本文用速度空间二维高速电子Ｆｏｋｋｅｒ－Ｐｌａｎｃｋ方程和原、副边回路方程组成的方程组描述托卡马克装置低浊经杂民流驱动宏观参数，研究了低混杂波电流驱动中的电场效应和原、副边回路相互作用应用该程序，初步模拟了ＨＬ－１装置的ＬＨＣＤ实验。     

高k栅介质对肖特基源漏超薄体SOI MOSFET性能的影响

研究了高k栅介质对肖特基源漏超薄体SOI MOSFET性能的影响.随着栅介质介电常数增大,肖特基源漏(SBSD) SOI MOSFET的开态电流减小,这表明边缘感应势垒降低效应(FIBL)并不是对势垒产生影响的主要机理.源端附近边缘感应势垒屏蔽效应(FIBS)是SBSD SOI MOSFET开态电流减小的主要原因.同时还发现,源漏与栅是否对准,高k栅介质对器件性能的影响也不相同.如果源漏与栅交叠,高k栅介质与硅衬底之间加入过渡层可以有效地抑制FIBS效应.如果源漏偏离栅,采用高k侧墙并结合堆叠栅结构,可以提高驱动电流.分析结果表明,来自栅极的电力线在介电常数不同的材料界面发生两次折射.根据结构参数的不同可以调节电力线的疏密,从而达到改变势垒高度,调节驱动电流的目的. 关键词： k栅介质')" href="#">高k栅介质 肖特基源漏(SBSD) 边缘感应势垒屏蔽(FIBS) 绝缘衬底上的硅(SOI)     

托卡马克中快波电流驱动下全波方程的数值求解

用全波方法研究环形对称托卡马克等离子体中离子回旋频率范围内(ICRF)的快波电流驱动(FWCD)问题,考虑有限拉莫尔半径(FLR)效应和平行色散,建立全波计算的物理模型—全波方程,通过对全波方程的数值求解得到快波在等离子体中激发的电场强度分布.结果表明:快波可以传播到高温高密度等离子体的中心;快波在磁轴附近发生了模式转换;快波可以驱动中心的等离子体电流以改善等离子体的平衡位型;平行电场比垂直电场小三个数量级,通过垂直方向的回旋共振和平行方向的穿越期磁泵效应达到驱动电流的目的.     

纳米金刚石的变温场发射

研究了温度变化对沉积在钛基底上的纳米金刚石的场发射特性的影响,发现纳米金刚石场发射电流随温度和电场的升高而增大,场发射特性偏离了传统的Fowler-Nordheim理论,场发射电流的稳定性基本没有变化.分析了场发射电流增大的机理,表明是由于纳米金刚石的尺度效应以及外电场下金刚石产生了大量的热载流子共同作用的结果.研究还表明基底钛在温度升高到一定程度后,在外加电场下会有较大的电流产生,对场发射造成较大的影响,表明基底钛具有一定的温度敏感性和电压敏感性. 关键词： 场发射 纳米金刚石 尺度效应 热载流子     

Generating spin currents in semiconductors with the spin Hall effect

We investigate electrically induced spin currents generated by the spin Hall effect in GaAs structures that distinguish edge effects from spin transport. Using Kerr rotation microscopy to image the spin polarization, we demonstrate that the observed spin accumulation is due to a transverse bulk electron spin current, which can drive spin polarization nearly 40 microns into a region in which there is minimal electric field. Using a model that incorporates the effects of spin drift, we determine the transverse spin drift velocity from the magnetic field dependence of the spin polarization.     

一种耦合外部电路的脉冲感应推力器磁流体力学数值仿真模型

为了深入研究脉冲感应推力器的工作原理,预测其推进性能,建立了一种耦合外部电路的磁流体力学模型,实现了对加速通道内等离子体二维流场结构演化过程及驱动电路放电过程的同步耦合求解.模拟计算所得美国MK-1推力器加速通道内的等离子体瞬态参数分布及推力器比冲、效率等性能参数均与实验数据一致;计算结果成功复现了推力器的工作物理图景.借助这一新模型,实现了对电路-等离子体双向耦合作用的定量分析,分析结果表明:耦合等离子体导致驱动电路等效电阻增大,电感减小;激励线圈与等离子体之间的互感随等离子体整体远离线圈表面而逐渐减小.