In order to enhance the conversion efficiency of ultra-intense laser energy into plasma leading to ion acceleration, we have performed an experiment with over-picosecond laser pulses having a relativistic intensity interacting with foam targets. We adjust the prepulse of the laser to control the plasma density near the critical density. The combination of hydrodynamic and particle-in-cell simulations suggest that the region of high energy density is induced in the near-critical plasma, leading to enhance the proton energy up to 23 MeV with the laser intensity of 6 × 10¹⁸ W/cm².

中文翻译：

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通过超过皮秒的激光脉冲与接近临界密度的泡沫靶标相互作用观察MeV能量离子

为了提高超强激光能量转换成等离子体的效率，从而导致离子加速，我们进行了一项实验，使用了皮秒级以上的相对脉冲强度与泡沫靶相互作用的激光脉冲。我们调整激光的预脉冲以将等离子体密度控制在临界密度附近。流体动力学和细胞内颗粒模拟的结合表明，在近临界等离子体中感应出高能量密度区域，从而在6×10 ¹⁸  W / cm的激光强度下将质子能量提高至23 MeV。²。