Influence of on-time on increased number density of excited nitrogen atoms downstream of pulse-modulated induction thermal plasmas

Abstract

The on-time is one operation parameter for pulse-modulated induction thermal plasmas (PMITPs). Its influence on the increased number density of excited nitrogen atoms flowing into a reaction chamber installed downstream of the Ar–N2 PMITP was investigated experimentally. The increased number density of excited nitrogen atoms downstream of the PMITP was found experimentally in our previous work (Tanaka et al 2006 Appl. Phys. Lett. 89 031501). The time evolution in the radiation intensity from the excited nitrogen atom was measured in Ar–N2 PMITP to obtain the on-time effect by changing the on-time in the wide range of 5–950 ms for different nitrogen gas flow rates. From these measurement results, an optimal on-time range was found for the increased density of the excited nitrogen atom by modulation of the coil current, which was equivalent to the averaged input power of 15–20 kW.