In the current study, plasma-polymerized methyl methacrylate (PP-MMA) generation on the inner surface of a silicone tube was performed in a capacitively coupled discharge reactor. The possibility of generating plasma inside the tube was analyzed and calculated by using optical emission spectroscopy (OES). A hollow cathode model was first proposed to determine whether plasma discharge would be generated inside the tube in the low-pressure regime. Since the ignition of plasma inside the tube is necessary for the initiation of polymerization processes, the sheath thickness was calculated analytically. To achieve the goal, the electron temperature and density of plasma should be determined beforehand. In this study, the electron temperature and plasma density were measured and calculated according to OES spectra using both the modified Boltzmann plot and the line-ratio method. The results reveal that the occurrence of plasma inside the tube can be achieved if the tube’s inner diameter is greater than two times the thickness of the sheath. The effect of methyl methacrylate (MMA) monomer concentration on sheath thickness, and, hence, plasma generation and deposition, was investigated in the presence of argon plasma and MMA monomer. According to the study, one could control the ignition of plasma discharges inside the tube followed by plasma polymerization deposition. The OES method was also applied to identify the presence of the excited species related to the fragmented monomer. The deposition of PP-MMA films on the inner surface of the tube was confirmed via attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy.

A plasma system attached with one internal coil (for generating inductively coupled plasma) and two sputtering carbon targets was set up to deposit PP-MMA (plasma polymerized methyl methacrylate) thin films. PP-MMA was used as a model material in the present study. In the experiment, the working pressure and Ar/MMA flow ratio were varied, which resulted in the change in plasma conditions as well as the deposition rates. The optical emission spectroscopy (OES) method was applied to identify the presence of the excited species related to the fragmented monomer. In addition, the electron temperature and electron density were determined using the modified Boltzmann plot and line-ratio method, according to the measured OES spectra. The deposition rate of the PMMA film was then correlated with the determined plasma characteristics. To determine the vibrational modes of the deposited PP-MMA films, Fourier transformed infrared spectrometry (FTIR) was used. The highest deposition rate of PP-MMA could be obtained with the optimized working pressure and Ar/MMA volume ratio. This could be related to the plasma characteristics that contribute to the fragmentation of the monomer in the plasma.

We present a comparative study of electron density obtained in a low-temperature plasma by the cutoff probe and compare the results with data from both the hairpin and the Langmuir probes. The measurements with different probes were conducted in a DC discharge generated by an iron hollow cathode under identical experimental conditions. This comparative analysis provides insight into the reliability and consistency of electron density measurements across different probe types in this specific experimental setup. The information acquired from the cutoff and hairpin probes enables electron density measurements within the frequency range limitations of the instruments. Measurements of electron density are performed in a mixture of argon and oxygen at a low pressure of 5 Pa, in dependence on the discharge current and Ar:O2 mixture ratio. A qualitative discussion of the obtained results is provided.

We present a hot tungsten cathode system (HTCS) to study the interactions between low-temperature plasma and thin metal layers sputtered onto both conductive and non-conductive substrates. This research aims to understand material selection for liquid metal divertor (LMD) applications. Before interaction in the hot cathode system, we prepared three series of samples using high power impulse magnetron sputtering. Plasma parameters were measured using Langmuir probes in a DC discharge generated under identical experimental conditions. The morphology of samples after interaction in a hot tungsten cathode was studied using scanning electron microscopy.

Understanding the behaviour of multicomponent plasmas under magnetically confined low-pressure conditions is essential for advancing plasma-assisted chemical conversion and materials processing. Here, we report a comprehensive diagnostic of a ternary He:N ₂ :CO ₂ plasma sustained in a DC driven non-segmented cylindrical magnetron. Using complementary optical emission spectroscopy and Langmuir probe measurements, we resolve the electron temperature, electron density, rotational and vibrational temperatures across a range of discharge conditions. The gas mixture (in ratio of 3:2:1) enables controlled probing of energy transfer pathways in a plasma active environment. By systematically varying magnetic field strength, discharge current, and operating pressure while maintaining constant gas flow, we reveal distinct non-linear responses of electron kinetics and molecular excitation to magnetron confinement. This work uniquely focuses on establishing a ‘thermal decoupling’ regime where strong magnetic confinement (40 mT) enables the plasma to maintain high electron densities ( ∼ 10 16 m − 3 ) for reactivity while keeping the neutral gas background at near ambient temperatures, effectively preventing the efficiency losses typically caused by gas phase heating. The results elucidate the interplay between magnetic confinement, electron energy distribution, and vibrational excitation in ternary plasmas, providing quantitative insight into plasma mechanisms relevant to low pressure magnetron systems.