Atmospheric pressure cold plasma jets (APCPJs) typically exhibit a slender, conical structure, which imposes limitations on their application for surface modification due to the restricted treatment area. In this paper, we introduce a novel plasma jet morphology known as the large-scale cold plasma jet (LSCPJ), characterized by the presence of both a central conical plasma jet and a peripheral trumpet-like diffuse plasma jet. The experimental investigations have identified the factors influencing the conical and the trumpet-like diffuse plasma jet, and theoretical simulations have shed light on the role of the flow field and the electric field in shaping the formation of the LSCPJ. It is proved that, under conditions of elevated helium concentration, the distributions of impurity gas particles and the electric field jointly determine the plasma jet’s morphology. High-speed ICCD camera images confirm the dynamic behavior of plasma bullets in LSCPJ, which is consistent with the theoretical analysis. Finally, it is demonstrated that when applied to the surface treatment of silicone rubber, LSCPJ can achieve a treatment area over 28 times larger than that of APCPJ under equivalent conditions. This paper uncovers the crucial role of impurity gases and electric fields in shaping plasma jet morphology and opens up the possibility of efficiently diversifying plasma jet generation effects through external electromagnetic fields. These insights hold the promise of reducing the generation cost of plasma jets and expanding their applications across various industrial sectors.

中文翻译：

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大型冷等离子体射流：产生机理及应用效果

大气压冷等离子体射流（APCPJ）通常呈现细长的圆锥形结构，由于处理区域有限，这限制了其表面改性的应用。在本文中，我们介绍了一种新型等离子体射流形态，称为大规模冷等离子体射流（LSCPJ），其特征是同时存在中心圆锥形等离子体射流和外围喇叭状扩散等离子体射流。实验研究确定了影响锥形和喇叭状扩散等离子体射流的因素，理论模拟揭示了流场和电场在 LSCPJ 形成中的作用。实验证明，在氦浓度升高的条件下，杂质气体颗粒的分布和电场共同决定了等离子体射流的形貌。高速ICCD相机图像证实了LSCPJ中等离子子弹的动态行为，这与理论分析一致。最后证明，在同等条件下，LSCPJ应用于硅橡胶表面处理时，可以实现比APCPJ大28倍以上的处理面积。本文揭示了杂质气体和电场在塑造等离子体射流形态中的关键作用，并开辟了通过外部电磁场有效多样化等离子体射流生成效果的可能性。这些见解有望降低等离子射流的生成成本并扩大其在各个工业领域的应用。