Transition of Proton Energy Scaling Using an Ultrathin Target Irradiated by Linearly Polarized Femtosecond Laser Pulses
Transition of Proton Energy Scaling Using an Ultrathin Target Irradiated by Linearly Polarized Femtosecond Laser Pulses
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DOI：
10.1103/physrevlett.111.165003
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发表时间：
2013-10-16
影响因子：
8.6
通讯作者：
Lee, Jongmin
中科院分区：
文献类型：
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作者：
Kim, I. Jong;Pae, Ki Hong;Lee, Jongmin
利用超强、超短激光脉冲进行粒子加速是相对论激光等离子体研究中最具吸引力的课题之一。我们报道了质子和/或离子在5 × 10（19）到3.3 × 10(20) W/cm(2)的强度范围内，通过线偏振，30秒激光脉冲照射在10到100纳米厚的聚合物目标上。研究了质子能量与靶材厚度和靶材强度的关系，当激光强度为3.3 x 10(20) W/cm(2)照射10 nm厚靶材时，质子能量最大可达45 MeV。质子加速可以用一种混合加速机制来解释，包括靶正常鞘层加速、辐射压力加速和库仑爆炸辅助的自由膨胀。在混合加速机制下，观察到质子能量从I-1/2到I的转变。实验结果得到了二维和三维细胞内粒子模拟的支持。
Particle acceleration using ultraintense, ultrashort laser pulses is one of the most attractive topics in relativistic laser-plasma research. We report proton and/or ion acceleration in the intensity range of 5 x 10(19) to 3.3 x 10(20) W/cm(2) by irradiating linearly polarized, 30-fs laser pulses on 10-to 100-nm-thick polymer targets. The proton energy scaling with respect to the intensity and target thickness is examined, and a maximum proton energy of 45 MeV is obtained when a 10-nm-thick target is irradiated by a laser intensity of 3.3 x 10(20) W/cm(2). The proton acceleration is explained by a hybrid acceleration mechanism including target normal sheath acceleration, radiation pressure acceleration, and Coulomb explosion assisted-free expansion. The transition of proton energy scaling from I-1/2 to I is observed as a consequence of the hybrid acceleration mechanism. The experimental results are supported by two-and three-dimensional particle-in-cell simulations.