共查询到18条相似文献,搜索用时 46 毫秒
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强激光与等离子体之间相互作用,能够产生各种参量不稳定性过程和非线性效应。利用Karpman方法推导出横场包络所满足的非线性控制性方程,在一维情况下,获得孤波解。对孤波解进行分析,发现波包孤子的半宽反比于振幅;分析磁化等离子体中各参量对孤波半宽的影响。结果表明,在右旋圆偏振激光情况下,随着电子数密度的增大,孤波的半宽逐渐减小,而当磁场强度增大时,孤波的半宽逐渐增大;在左旋圆偏振激光情况下,随着电子数密度的增大,孤波的半宽逐渐增大,而当磁场强度增大时,孤波的半宽逐渐减小。 相似文献
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在超短超强飞秒SILEX-Ⅰ激光装置上,开展了薄膜靶激光质子加速的实验研究。实验发现激光预脉冲、靶厚度对质子加速有很大的影响。在激光强度3×1018~3×1019 W/cm2条件下,采用前表面厚度为3 μm铜、后表面镀4 μm厚CH靶,质子的最大能量达到3.15 MeV。而对190 nm厚CH膜靶,质子的最大能量为0.54 MeV。初步研究了激光偏振对质子加速的影响,相同激光功率条件下,圆偏振激光加速产生的质子最大能量略低于P偏振打靶。这些结果与靶后鞘层加速机制相一致。 相似文献
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在超短超强飞秒SILEX-Ⅰ激光装置上,开展了薄膜靶激光质子加速的实验研究。实验发现激光预脉冲、靶厚度对质子加速有很大的影响。在激光强度3×1018~3×1019W/cm2条件下,采用前表面厚度为3μm铜、后表面镀4μm厚CH靶,质子的最大能量达到3.15 MeV。而对190 nm厚CH膜靶,质子的最大能量为0.54 MeV。初步研究了激光偏振对质子加速的影响,相同激光功率条件下,圆偏振激光加速产生的质子最大能量略低于P偏振打靶。这些结果与靶后鞘层加速机制相一致。 相似文献
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本文介绍采用拍频曲线晶振基准法首次在Uniphase 1007型长寿命商品He-Ne激光管上实现了无压电陶瓷调谐元件的塞曼双频稳频,采用可调永磁供磁,达到光频长期漂移5×10~(-9);双频双线偏振分离度1/60;双线偏振正交度89.5°;入锁及锁定情况良好.给出了塞曼双频激光器的调试技术.描述了输出光束偏振状态和纵模数关系的一个物理现象. 相似文献
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二极管激光泵浦固体激光器和稳频研究 总被引:1,自引:0,他引:1
用调制法布里-珀罗干涉仪方法稳定二极管激光泵浦的NdYVO4单频激光器的频率。在锁定情形下,激光频从自由运行慢漂移1.43MHz/s和抖动±2.5MHz分别改善到75.75kHz/s和±1MHz 相似文献
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本文分析了右旋偏振波穿透高密度等离子体的条件,给出了理论根据及原理性实验的结果。实验证实,当ω_(ce)≈2ω时,右旋偏振波(哨波模)可以穿透很高密度的等离子体(ω_(pe)~2>>ω~2),并可能成为克服“再入”时“黑障”的一个途径。 相似文献
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激光等离子体加速器能够在cm尺度内产生GeV量级的高品质电子束,为研制台式化自由电子激光提供驱动源。但是受限于激光等离子体加速中的难点和现有技术发展,电子束的品质难以达到自由电子激光的需求,尤其在稳定性、发散角和能散等方面,阻碍了台式化自由电子激光的研制。介绍了基于激光等离子体加速器的自由电子激光的最新进展,整理了目前高增益自由电子激光实验过程中存在的主要挑战和对应的解决方案与实验进展,并展望未来的发展方向。最近的研究结果证明,通过控制和优化激光等离子体加速器的注入和加速过程产生的高品质电子束可以在指数增益区域实现自发辐射放大,产生高增益的辐射,这也推动基于激光等离子体加速器的自由电子激光研究进入了一个新的阶段。 相似文献
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P. Mora 《The European physical journal. Special topics》2009,175(1):97-104
The acceleration of electrons in laser plasma interaction has been observed since the seventies, when it was initially considered
as a deleterious effect, as, in the inertial fusion context, the so-called suprathermal electrons preheat the target. However,
it has been quickly observed that a large benefit could be taken from these electrons. Two main directions are now followed.
In the first direction, one tries to accelerate electrons to high energy, presently in the GeV range. The electrons may originate
from a pre-accelerated beam, or directly from a gas target instantaneously transformed in a plasma by the ultra-intense laser
pulse. In the second direction, one tries to transfer the energy of the electrons to fast ions, especially protons, presently
in the few tens of MeV range. Thin targets are used for this transformation, the electrons being accelerated at the front
of the target, while the ions may originate from the front part or the back part of the target, or from inside the target,
depending on the parameters of the experiment. While the maximum energy was the initial goal of the pioneer experiments, there
are now strong experimental efforts to improve the quality of the beams, in terms of luminosity, emittance, and energy spectrum.
In the recent years, quasi-monoenergetic beams were obtained both for electrons and for ions. 相似文献
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Fennel T Döppner T Passig J Schaal Ch Tiggesbäumker J Meiwes-Broer KH 《Physical review letters》2007,98(14):143401
We have measured the energy and angular-resolved electron emission from medium-sized silver clusters (N approximately 500-2000) exposed to dual laser pulses of moderate intensity (I approximately (10(13-14) W/cm2). When the second pulse excites the plasmon resonantly, we observe enhanced emission along the laser polarization axis. The asymmetry of the electron spectrum is strongly increasing with electron energy. Semiclassical simulations reveal the following mechanism: Electrons bound in highly excited states can leave, return to, and traverse the cluster. Those electrons that return at zero plasmon deflection and traverse the cluster during a favorable plasmon half-cycle can experience maximum acceleration by the evolving polarization field. As a result of these constraints energetic electrons are emitted in direction of the laser polarization axis in subcycle bursts. 相似文献
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在低密等离子体通道中, 横向有质动力可以有效调制电子的横向振荡过程. 一方面, 横向有质动力可以向外推动电子, 增大电子横向振荡振幅, 减小失相率, 使电子获得能量增益; 另一方面, 横向有质动力也可以通过对失相率的非线性调制来降低失相率, 在电子横向振荡振幅很小的情况下导致激光直接加速. 横向有质动力调制的大小由等离子体密度、激光强度和束宽共同决定. 三维模型结果也证实可以通过参数放大实现激光直接加速, 弥补了准二维模型的局限性. 相似文献
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研究了激光辐射压驱动的两级质子加速的相关问题。当超短超强激光脉冲与处在背景等离子体前方的薄固体平靶相互作用时,在固体靶后部形成一个电子层-离子层组成的双层结构。在激光的不断推进下,双层结构在背景等离子体里以一定速度传播,可以看成运动在背景等离子体中的电场。这样,在背景等离子体中的质子被这个运动电场捕获并能加速到很高的能量。通过二维PIC模拟方法和理论分析研究了质子加速的相关问题。研究结果表明,被加速质子的最大能量达到20GeV。 相似文献
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H. Hora 《Optical and Quantum Electronics》1970,2(4):201-214
Ruby laser intensities exceedingI
* - 1014 W/cm2 create a predominant acceleration of dense plasma due to nonlinear collisionless interaction resulting mainly from collective effects. Recoil causes confinement of the plasma interior in the form of a superlinearly increased radiation pressure. Similar nonlinear forces produce self-focusing in plasmas at a threshold laser power of only 105 to 106 W. The resulting filaments have intensitiesI
*, from which their diameter can be determined in agreement with measurements of Korobkin and Alcock. These high intensities should allow some observed properties of laser produced plasmas (keV ions, linear increase of the ion charge) to be interpreted on the basis of the nonlinear acceleration described. 相似文献
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The effect of ultrastrong magnetic fields generated in a relativistic-intensity subpicosecond laser plasma on the acceleration of fast electrons was studied. It is shown that resonance electrons can continuously accumulate energy from the circularly polarized laser field in the presence of a longitudinal magnetic field. For the linear polarization and a transverse magnetic field, energy accumulation has a pulse-periodic character, and the electron trajectories correspond to electron rotation in the Larmor orbit in a quasi-stationary magnetic field, while the energy strongly oscillates. In both cases, electron energy may attain values higher than 100 MeV for intensities of 1020 W/cm2. 相似文献
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A. Pukhov I. Kostyukov T. Tückmantel Ph. Luu-Thanh G. Mourou 《The European physical journal. Special topics》2014,223(6):1197-1206
We consider a possibilty to use an echelon of mutually coherent laser pulses generated by the emerging CAN (Coherent Amplification Network) technology for direct particle acceleration in periodic plasma structures. We discuss resonant and free streaming configurations. The resonant plasma structures can trap energy of longer laser pulses but are limited to moderate laser intensities of about 1014?W/cm2 and are very sensitive to the structure quality. The free streaming configurations can survive laser intensities above 1018?W/cm2 for several tens of femtoseconds so that sustained accelerating rates well above TeV/m are feasible. In our full electromagnetic relativistic particle-in-cell (PIC) simulations we show a test electron bunch gaining up to 200?GeV over a distance of 10.2?cm only. 相似文献