相对论激光与等离子体相互作用中的高能离子产生
文献类型：学位论文
| 作者 | 宾建辉 |
| 学位类别 | 硕士 |
| 答辩日期 | 2009 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 雷安乐 |
| 关键词 | 相对论激光 激光等离子体相互作用 高能离子 粒子模拟 |
| 其他题名 | Energetic ion generation in relativistic laser-plasma interaction |
| 中文摘要 | 随着激光技术的发展，人们已经能够获得聚焦强度高达1022W/cm2、脉冲宽度小于1ps的相对论激光脉冲。这样的超短超强激光与等离子体相互作用中产生的离子束具有方向性好，能量高，持续时间短等特点，在成像、癌症治疗、快点火等方面有很大的应用前景，使其成为近年来的研究热点。本论文主要进行了相对论激光与等离子体靶相互作用过程中离子加速的研究工作，具体如下： 1 采用二维particle in cell粒子模拟程序研究了强激光脉冲与薄膜靶相互作用中的高能质子产生。模拟采用了三种不同表面结构：前凹、前凸和平面靶。我们发现被加速的质子的最大能量由靶前表面结构决定，前凹靶情况下得到的质子能量最高。这是由于前凹靶前表面结构导致的激光吸收增加和激光诱导热电子汇聚共同作用的结果。 2 采用数值解析和计算机模拟讨论了圆偏振激光脉冲与双层靶作用时的单能质子产生。双层靶的前表面为重离子层，后表面为小的轻离子粘着层。Particle-in-cell模拟表明双层靶情况下可以避免多维效应，得到高质量的单能离子束。模拟结果发现重离子的荷质比和离子层各自的厚度对离子能谱有很大影响。 3 用二维particle-in-cell模拟程序研究了等离子体初始温度对线偏振强激光与物质相互作用过程中高能质子产生的影响。观察到不同的等离子体初始温度会影响靶前激波的产生时间，进而影响质子产额。数值模拟显示当等离子体初始温度适度增大时可以得到更高的质子产额。 |
| 英文摘要 | The development of laser technology has made available ultra intense (1022W/cm2) ultra short (< 1ps) relativistic laser pulses. Ion beams generated from intense-laser interactions with matter exhibit high energy, short duration, and high directionality. This enables these ions as dream beams for many potential applications, such as in imaging, ion cancer therapy, and fast ignition in inertial confinement fusion, etc. In this paper, energetic ion generation in relativistic laser-plasma interaction is introduced and some results are presented below. 1 Energetic proton generation from thin foil targets by ultra intense laser pulse is investigated using two-dimensional particle-in-cell simulations. Foil targets with concave, flat, and convex front surfaces are considered. The maximum energy of the accelerated protons depends on the front-surface curvature, and the highest energy protons are from the concave foil. The result can be attributed to an enhancement of the generation as well as concentration of the laser-driven hot electrons by the concave surface. 2 Monoenergetic ion beam generation from circular-polarized laser-pulse interaction with a double-layer target is considered. The front layer consists of a heavy-ion plasma, and the rear layer is a small thin coating of light-ion plasma. Particle-in-cell simulation shows that the multidimensional effects in the ion radiation pressure acceleration are avoided and a highly monoenergetic light-ion beam can be produced. Our simulations reveal that the charge-mass ratio of heavy ions in the front layer and the thicknesses of both layers can strongly affect the proton energy spectra. 3 The influence of initial plasma temperature on energetic proton generation from the intense laser plasma interaction is studied using 2D particle-in-cell simulation. It is found that the time required for the shock formation can be affected by the initial plasma temperature, which influences the energetic proton generation in the shock. Simulations show that high proton yield can be obtained by increasing the initial plasma temperature moderately. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16405]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 宾建辉. 相对论激光与等离子体相互作用中的高能离子产生[D]. 中国科学院上海光学精密机械研究所. 2009. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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