标题： 固体靶材稀薄预等离子体中的激光不透明度由于量子电动力学效应 显示英文标题

标题： Laser opacity in underdense preplasma of solid targets due to quantum electrodynamics effects

摘要： 我们研究了在由放大自发辐射（ASE）产生的相对论性稀疏预等离子体存在的情况下，下一代10 PW $-$ 200 PW 激光脉冲与固体靶的相互作用。 由于通过量子电动力学（QED）过程产生电子-正电子对和 $\gamma$-射线光子，激光穿孔和相对论透明性受到强烈抑制。 形成了密度高于初始预等离子体密度的粒子对等离子体，抵消了穿孔产生的无电子通道。 这种以粒子对为主的等离子体可以阻挡激光传输并触发类似雪崩的QED级联，有效地将激光能量传递给光子。 这使得在这一功率水平下，1-$\rm\mu m$-尺度长度的稀疏预等离子体对激光脉冲完全不透明。 因此，QED引起的不透明性比经典等离子体物理预期的对这种脉冲在固体靶实验中的对比度要求要高得多。 我们的模拟显示，例如，从带有预等离子体的固体背面产生的质子加速将受到严重影响。 显示英文摘要

摘要： We investigate how next-generation laser pulses at 10 PW $-$ 200 PW interact with a solid target in the presence of a relativistically underdense preplasma produced by amplified spontaneous emission (ASE). Laser hole boring and relativistic transparency are strongly restrained due to the generation of electron-positron pairs and $\gamma$-ray photons via quantum electrodynamics (QED) processes. A pair plasma with a density above the initial preplasma density is formed, counteracting the electron-free channel produced by the hole boring. This pair-dominated plasma can block the laser transport and trigger an avalanche-like QED cascade, efficiently transfering the laser energy to photons. This renders a 1-$\rm\mu m$-scalelength, underdense preplasma completely opaque to laser pulses at this power level. The QED-induced opacity therefore sets much higher contrast requirements for such pulse in solid-target experiments than expected by classical plasma physics. Our simulations show for example, that proton acceleration from the rear of a solid with a preplasma would be strongly impaired.