The effect of the size of the rods at the structured silicon target surface on the parameters of the plasma produced when the target is exposed to a high-contrast femtosecond laser pulse with an intensity of 2 10¹⁸ W cm⁻² is investigated. It is shown that irradiation of a target with subwavelength rods (∼ 100 nm in diameter) provides a significant (up to 250 keV) increase in the temperature of hot plasma electrons and their number in comparison with those obtained in the case of a plane target. It was found that in this case the yield of hard X-ray radiation increases several-fold. The observed effect can be attributed to increased absorption and particle motion in a complex field near plasma nonuniformities. It is shown that the presence of rods with a characteristic size of ∼ 1 μm promotes an increase in the production efficiency of multiply charged silicon ions. The result obtained is apparently associated with the radiation penetration between the rods and with collisional ionisation of particles as they fly into vacuum from deeper target layers.

当靶暴露于强度为 2 10 ¹⁸ W cm ^-2的高对比度飞秒激光脉冲时，结构化硅靶表面的棒尺寸对产生的等离子体参数的影响被调查。结果表明，与在平面靶的情况下获得的温度相比，用亚波长棒（直径约 100 nm）照射靶会显着（高达 250 keV）增加热等离子体电子的温度及其数量. 发现在这种情况下，硬 X 射线辐射的产量增加了几倍。观察到的效应可归因于在等离子体不均匀性附近的复杂场中增加的吸收和粒子运动。结果表明，特征尺寸约为 1 μm 的棒的存在促进了多电荷硅离子的生产效率的提高。获得的结果显然与棒之间的辐射穿透以及粒子从更深的目标层飞入真空时的碰撞电离有关。