In this study, the heat deposition characteristics of laser filaments formed by femtosecond laser pulses with different initial energy under influences of external focusing are numerically investigated by means of (3 D + 1)-dimensional numerical simulations. The results indicate that the numbers and intensity of filaments increase with growth of the input energy. The formation of multiple filaments limits the increase of filament length. When fixing the input energy, radius of the filament becomes narrow while its numbers and intensity are both enhanced under strong focusing. Under stronger focusing, the filaments can also deposit higher laser energy and result in larger energy deposition rate for laser beams with a given input energy, which further leads to dramatic increase in local temperature and pressure. These are likely to affect the filament induced airflow velocity and eventually the mass of formed snow in the cold supersaturated cloud chamber.

中文翻译：

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飞秒多根飞秒激光脉冲热沉积特性的数值研究

在这项研究中，通过（3 D +1）维数值模拟，对由具有不同初始能量的飞秒激光脉冲形成的激光灯丝在外部聚焦的影响下的热沉积特性进行了数值研究。结果表明，细丝的数量和强度随着输入能量的增加而增加。多根细丝的形成限制了细丝长度的增加。固定输入能量时，灯丝的半径会变窄，而在强聚焦下灯丝的数量和强度都会增加。在更强的聚焦条件下，灯丝还可以沉积更高的激光能量，并导致具有给定输入能量的激光束具有更大的能量沉积速率，从而进一步导致局部温度和压力急剧增加。