Effect of Small Focus on Electron Heating and Proton Acceleration in Ultrarelativistic Laser-Solid Interactions
Effect of Small Focus on Electron Heating and Proton Acceleration in Ultrarelativistic Laser-Solid Interactions
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DOI：
10.1103/physrevlett.124.084802
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发表时间：
2020-02-26
影响因子：
8.6
通讯作者：
Kondo, K.
中科院分区：
文献类型：
--
作者：
Dover, N. P.;Nishiuchi, M.;Kondo, K.
实验研究了5 × 10(21) Wcm（-2）的超强激光脉冲与薄箔的相互作用对粒子的加速作用。电子束参数随光斑尺寸的减小而变化，而不仅仅是激光强度的减小，从而导致温度和散度的降低。特别是，在紧聚焦点处，由于加速度长度不足，温度饱和。这些依赖关系影响了鞘加速质子，其表现出比广泛使用的标度定律更差的点尺寸标度。因此，在某些应用中，通过使用非常小的焦点来最大化激光强度会降低回报。
Acceleration of particles from the interaction of ultraintense laser pulses up to 5 x 10(21) Wcm(-2) with thin foils is investigated experimentally. The electron beam parameters varied with decreasing spot size, not just laser intensity, resulting in reduced temperatures and divergence. In particular, the temperature saturated due to insufficient acceleration length in the tightly focused spot. These dependencies affected the sheath-accelerated protons, which showed poorer spot-size scaling than widely used scaling laws. It is therefore shown that maximizing laser intensity by using very small foci has reducing returns for some applications.