【摘 要】
：
人工表面等离子体激元(Spoof surface plasmons,SSP)[1]是存在于周期金属结构表面的一种特殊的电磁极化模。由于其具有很强的近场增强效应,通过外加电子束在周期金属光栅表面激发并放大 SSP 有望发展成为一种新型的高效率的真空太赫兹电子学源[2]。前期研究发现在满足电子束与 SSP 色散匹配的条件下,SSP 能够被有效地激发并得到放大,并且研究了电子束参数(电流、电压和发射形状
【机 构】
：
北京大学信息科学技术学院,北京,100871
论文部分内容阅读
人工表面等离子体激元(Spoof surface plasmons,SSP)[1]是存在于周期金属结构表面的一种特殊的电磁极化模。由于其具有很强的近场增强效应,通过外加电子束在周期金属光栅表面激发并放大 SSP 有望发展成为一种新型的高效率的真空太赫兹电子学源[2]。前期研究发现在满足电子束与 SSP 色散匹配的条件下,SSP 能够被有效地激发并得到放大,并且研究了电子束参数(电流、电压和发射形状)和光栅结构参数(槽深和槽宽)对输出功率的影响[2]。本文在此基础上,通过理论计算[3,4]和基于 FDTD 的粒子模拟软件仿真进一步研究 了外加磁场强度和发射电子束厚度对输出功率的影响。经过研究发现在满足其他最佳的互作 用条件下[2],电子束的发射厚度会显著影响互作用输出结果：在保持外加磁场强度不变的情 况下,存在一个最佳的电子束厚度使得输出功率最大。而给定最佳的发射电子束厚度,增大 外加磁场强度,能够在一定范围内提高输出功率。减小电子束的发射厚度能够使得电荷的空 间效应变得显著,而提高外加轴向约束磁场的强度能够有效约束电子束使得互作用效率得到 提高。本文对外加轴向磁场和电子束发射厚度的研究对发展基于人工表面等离子体激元的太 赫兹真空电子学源具有重要意义。
其他文献
Rare earth elements(REEs)of fifty-eight Late Permian coal samples from Liupanshui Coalfield,western Guizhou of China,were determined by Inductively Coupled-plasma Mass Spectrometry(ICP-MS).
During manufacture of permanent magnets(Sm2Co7 magnets),around 20-40 percent of the slurry would be generated from the machining process.It is estimated that 20 tons of SmCo-containing slurry is produ
Taking the roasting ore water leaching process in Baotou rare earth concentrate sulfuric acid roasting as an object,the effect of roasting leaching temperature,leaching time,roasting ore granularity o
There is abundant rare-earth element in our country,but it is very fragmented in the earths crust,and it is very difficult to mining or mining cost is extremely high.
According to the needs of environmental protection for the development of rare earth mineral resources,and with the requirements of the environmental impact assessment of the rare earth industry,Guide
Now days high current electron beam(HCPEB)is an important tools for modification of materials surface,but microcracks and crater structures generated during the process of HCPEB treatment limited its
In this paper,measures such as modification of rare earth Nd,heat treatment and extrusion process was adopted to treat the hypereutectic A390 Al-Si alloy(16.0wt%-18.0wt%Si),aiming at obtaining an impr
In this paper,Different content of aluminium alloy(3004 aluminum alloy)was added to the Zn-5%Al-0.1%RE alloy coating to study effects of aluminum scrap on microstructure and properties of the coating.
The Zn-23%Al-0.3%Si coating is a novel alloy coating which is developed by Canada Comico company.The Zn-23Al-0.3Si-XMg coating is manufactured by adding different content of Mg to Zn-23%Al-0.3%Si coat
等离子体破裂是托卡马克装置放电过程中经常发生的突发性事件,在破裂过程中,等离子体内能(热能和磁能)会在很短的时间内(几个毫秒)沉积到第一壁上去,从而会对装置内部结构造成很大的破坏性[1]；这也是未来的ITER 等聚变装置所必须考虑和解决的关键问题之一.作为未来ITER 装置开展等离子体破裂缓解备选杂质注入方式的高压气体注入(massive gas injection,MGI)已经在国际上大多数托卡