An atmospheric-pressure non-thermal plasma jet driven by high frequency alternating current and operating on N 2 and N 2 /O 2 gas mixture is investigated. The plasma jet can reach 55 mm in length at a gas flow rate of 2500 l/h. The gas temperature at a distance of 4 mm from the nozzle is close to room temperature. Optical emission spectroscopy is employed to investigate the important plasma parameters such as the excited species, rotational temperature, vibrational temperature, and excitation temperature under different discharge conditions. The results show that the plasma source operates under non-equilibrium conditions. The absolute irradiance intensity of the vibrational band N 2 (C-B) in the active region is measured. Taking into account the irradiance intensity of N 2 (C-B,0-0) and N 2 (B-X,0-0) as well as measured current, the electron density, which is determined by considering direct and step-wise electron impact excitation of nitrogen emission, reaches a maximum value of 5.6 Â 10 20 /m 3. V

Estimation of electron temperature and density of the decay plasma in a laser-assisted discharge plasma extreme ultraviolet source by using a modified Stark broadening method An atmospheric-pressure non-thermal plasma jet excited by high frequency alternating current using nitrogen is developed and the electron density in the active region of this plasma jet is investigated by two different methods using optical emission spectroscopy, Stark broadening, and irradiance intensity method. The irradiance intensity method shows that the average electron density is about 10 20 /m 3 which is slightly smaller than that by the Stark broadening method. However, the trend of the change in the electron density with input power obtained by these two methods is consistent. V C 2014 AIP Publishing LLC. [http://dx.

For the purpose of unveiling the parameters influencing the length of atmospheric pressure plasma plume, an over 165 cm long argon plasma plume is generated in the quartz tube attached to the nozzle of the device. Dependence of plasma length on discharge parameters such as applied voltage, frequency of power supply, and argon gas flow rate was investigated. Experimental results indicated that (a) the applied voltage plays crucial roles on plasma plume length, that is, the plasma plume length exponentially increases with the applied voltage, (b) the plasma plume length increases with frequency, more obviously when the applied voltage is higher, (c) the plasma plume length increases with argon gas flow rate, reaches its maximum at critical value of the gas flow rate, and then decreases again. An evaluation of the physical phenomena involved in streamer propagation, particularly of the energy balance, was investigated. The numerical results were qualitatively consistent with previous experimental results by successfully indicating the high velocity of “plasma bullet” and providing physical mechanism of energy balance determining streamer length.