双爆炸膜内壳层光电离X射线激光实验研究

报道了Pd-NaF,Pd-Cu,Ag-NaF和Ag-Cu耦合双爆炸膜内壳层光电离X射线激光的实验方法和一些实验结果。结果表明,在本实验条件下,激光加热NaF或Cu靶产生的1keV区的光子,可以增强Pd或Ag等离子体中类-Cu离子的3d¹⁰4p-3d⁹4s²软X射线发射的强度,但不足以形成X射线激光的输出。 关键词：     

线聚焦激光辐照Al靶所产生的紫外X射线谱线

本文叙述了采用线聚焦激光幅照Al靶所产生的高离化态离子的紫外X射线(XUV)谱线。利用Cowan的原子能级程序计算了不同离化态的离子谱线的波长和振子强度gf,辨认出140条离子谱线,其中有82条新谱线。 关键词：     

Dynamics of vortex–antivortex pair in a superconducting thin strip with narrow slits

In the framework of phenomenological time-dependent Ginzburg-Landau(TDGL) formalism,the dynamical properties of vortex-antivortex(V-Av) pair in a superconductor film with a narrow slit was studied.The slit position and length can have a great impact not only on the vortex dynamical behavior but also the current-voltage(Ⅰ-Ⅴ) characteristics of the sample.Kinematic vortex lines can be predominated by the location of the slit.In the range of relatively low applied currents for a constant weak magnetic field,kinematic vortex line appears at right or left side of the slit by turns periodically.We found such single-side kinematic vortex line cannot lead to a jump in the Ⅰ-Ⅴ curve.At higher applied currents the phase-slip lines can be observed at left and right sides of the slit simultaneously.The competition between the vortex created at the lateral edge of the sample and the V-Av pair in the slit will result in three distinctly different scenarios of vortex dynamics depending on slit length:the lateral vortex penetrates the sample to annihilate the antivortex in the slit;the V-Av pair in the slit are driven off and expelled laterally;both the lateral vortex and the slit antivortex are depinned and driven together to annihilation in the halfway.     

Vortex pinning and rectification effect in a nanostructured superconducting film with a square array of antidot triplets

We study the stability of vortices pinning and dynamics in a superconducting thin strip containing a square array of antidot triplets by using the nonlinear Ginzburg–Landau(GL) theory. Compared with the regular square array of circular holes, the vortices are no longer pinned inside the circular holes, but instead stabilized at the center of the antidot triplets depending on the geometry parameters. Moreover, the influences of the geometry parameters and the polarity of the applied current on the current–voltage(I–V) characteristics are also studied. The critical current for the sample turning into a normal state becomes smaller when the hole diameter D is smaller and the spacing B between the holes is larger. Due to the asymmetric pinning sites, our numerical simulations demonstrate that the positive and negative rectified voltages appear alternately in the resistive state of the sample under an ac current of square pulses.     

Simulation study of electron injection into plasma wake fields by colliding laser pulses using OOPIC

An electron injector concept for a laser-plasma accelerator has been developed which relies on the use of counter propagating ultrashort laser pulses. In this paper, we use OOPIC the fully self-consistent, twodimensional, particle-in-cell code to make a parameter study to determine the bunches that can be obtained through collisions of two collinear laser pulses in uniform plasma. A series of simulations show that one can obtain a short (<10fs) bunch with its charge of about 15pC, and energy spread of about 15%. We also discussed the variation of the transverse spot size of the electron bunch and found the bunch would undergo the betatron oscillations.     

Z箍缩初级实验平台模块样机

 正在研制的Z箍缩实验装置（Z-pinch Primary Test Stand,PTS装置）,由24个基于Marx发生器和水线的性能、结构相同的模块组成,各模块产生的大电流脉冲在绝缘堆上汇集后经磁绝缘传输线汇流到负载区,要求在不到0.2 Ω的低阻抗负载上得到8 MA以上电流,电流上升时间小于90 ns。研制的样机模块由Marx发生器、中间储能器、激光触发开关、脉冲形成线、水介质自击穿脉冲形成开关、三板型脉冲传输线组成,样机模块输出电流450 kA、输出电压2.2 MV、输出脉冲功率0.95 TW,从触发激光器信号输出到负载电压上升的系统延迟时间抖动小于6 ns。     

磁悬浮系统中多芯复合Nb3Sn超导线磁通跳跃的可调性研究

超导磁悬浮列车在加速启动的过程中,载有恒定大电流的超导线圈处在变化的磁场中,这会导致超导线圈发生磁通跳跃,从而降低线圈的载流能力.并且磁通跳跃会产生大量热量而使超导线圈温度急剧升高,严重时会导致超导线圈失超,所以对磁通跳跃的研究具有非常重要的科学意义.Nb₃Sn超导线是由多根微米级的超导芯丝、铜和环氧树脂形成的复合结构.本文通过约束每根芯丝的静电流为零的二维模型来分析三维绞扭效应,研究了超导线在交变磁场和恒定电流下的磁热不稳定性行为.通过分析交变磁场的幅值和频率对Nb3Sn超导线磁通跳跃的影响,发现当磁场幅值不变时,初次发生磁通跳跃的磁场阈值B_th随频率非单调变化.而当频率一定时,初次发生磁通跳跃的磁场阈值B_th随交变磁场幅值单调变化.此外,随着幅值的减小,发生磁通跳跃的频率区间先变大后变小,直到某个临界频率后超导线不再发生磁通跳跃.本文的研究结果能够为调控超导线的磁热不稳定性行为提供理论依据.     

用henke X光源标定Kodak SWR底片的响应曲线

利用Henke X光源,通过电子激发方式,获得了C的K_a线(277eV)和Mo的L线(193eV),通过X光激发方式,获得了Al的K_a线(1.5keV)和Ti的K_a线(4.5keV)。利用流气式正比计数管监测X射线强度,测得了Kodak SWR底片对以上四种能量的X光的响应曲线。     

类氖锗的X射线激光增益及其传输特性研究

在神光(10¹²W)装置上,用1.06μm激光加热片状锗靶,用袖珍式掠入射光栅谱仪测量了类氖锗离子的3S—3P激光跃迁线的增益系数和X射线激光的传输特性,得到的结果为:波长为19.638,23.224,23.627,24.743和28.643nm的5条激光跃迁线的增益系数分别为3.06,3.99,3.72,2.36和4.59cm^-1;当等离子体长度为18mm时,相应的X射线激光的发散角约为12mrad,发射X射线激光的等离子体厚度约为200μm,X射线激光峰值强 关键词：