Atmospheric Pressure Plasma Jet (APPJ) arrays are considered as one of the most promising methods for uniform plasma processing of large uneven surfaces. To improve the downstream uniformity and enhance the surface treatment effects, it is important to reveal the mechanisms of the jet‐to‐jet interactions of plasma plumes in the jet array. In this paper, the electrical, optical, and fluid characteristics of the He and Ar three‐channel one‐dimensional (1D) plasma jet arrays with cross‐field needle‐ring electrode structure are studied and compared. It is found that there are divergences in the outside plumes of the propagation trajectory by the repellency of the plasma bullets and the spatial uniformity of the He and Ar plasma jet arrays can be improved with a lower applied voltage and a higher gas flow rate. The deflection angle of side plumes with respect to the central one of He is larger than that of Ar jet array due to the lighter molecular weight and better discharge synchronization. The experimental results show that Ar jet array is more controllable and stable and is more suitable for the design of the practical, simpler, and cheaper scalable plasma jet arrays.

Uniform and stable reactivity of atmospheric pressure plasmas is a prerequisite for most applications in fields ranging from materials’ surface processing, environment protection, to energy conversion. Dielectric barrier discharges (DBDs) are among the most promising plasmas to satisfy these requirements. However, the unpredictable and uncontrollable transitions between discharge modes, the limited understanding of the DBD ignition and extinction processes, and the complexity of plasma chemistries and reactions with admixture gases restrict their adoption in industry. Here, we report a practically relevant and elegant solution based on using customized nanosecond (ns) pulse excitation and precise addition of oxygen to an Ar flow. The effects of ns pulses and oxygen on the uniformity and reactivity of the DBD are investigated via quantifying the gap voltage U_g and the discharge current I_g from the current–voltage measurements and quantitative discharge imaging. The electron density, n_e, is estimated with U_g and I_g. With increasing U_g, more electron avalanches are ignited and overlap, which facilitate n_e, T_e, and discharge uniformity, while high U_g induces excessive electrons generated with high ionization rates, resulting in the distortion of the space electric field and reduced stability and uniformity. A small amount of added oxygen favors the production of electrons. Overdosed oxygen molecules capture electrons causing a drop in n_e and T_e and couple with the effect of the electrical field resulting in the filamentary discharges or complete plasma extinction. The mechanism of the effects of ns pulses and oxygen addition on the uniformity and reactivity of plasmas is based on the electrical measurements and discharge image analysis and is cross-validated by optical emission spectra measurements and the ratio of the Ar intensities’ calculations as indicators of the variation in n_e and T_e. The results in this work contribute to the realization and controllability of uniform, stable, and reactive plasmas at atmospheric pressure.

Surface flashover of insulating materials induced by pollution and moisture environment is one of the main reasons for the damage of power system and electrical equipment. The improvement of the insulating materials surface hydrophobicity is key important, which can prevent the pollutants and water attachment, and enhance the insulating performance. In this paper, the super‐hydrophobic film is formed on the surface of epoxy resin by a one‐dimensional (1D) argon (Ar) jet array driven by nanosecond pulse power supply with hexamethyldisiloxane (HMDSO) addition. The influences of the processing time and HMDSO content on the epoxy resin surface hydrophobicity are investigated. It shows that with 0.04 % HMDSO, the jet array achieves a best hydrophobic treatment effect on the epoxy resin surface. After 60 s treatment, the apparent contact angle (ACA) of the epoxy resin surface increases from 60.3° of the untreated surface to 150.0°. The wettability of epoxy resin surface does not change too much as the treatment time beyond 60 s. The maximum ACA value 153.4° appears at 120 s processing time, which is just slightly higher than that of 60 s treatment time. The epoxy resin surface morphology and chemical feature before and after plasma processing are characteristics by the scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infra‐red spectroscopy and X‐ray photoelectron spectroscopy. It shows that the treated epoxy resin surface is covered with dense coral like particles in nanoscales, the original C=O、C‐H and other organic functional groups are replaced by Si‐(CH ₃ ), Si‐O‐Si and other silicon containing groups, and the Si content increases from 0.4% to 28.0%. The experimental results provide important references to develop jet array as an efficient tool to enhance the surface hydrophobicity and insulating performance of insulating materials.