Atmospheric pressure of nitrogen plasmas in a ferroelectric packed-bed barrier discharge reactor. Part II. Spectroscopic measurements of excited nitrogen molecule density and its vibrational temperature

For pt.I see ibid.(vol.11 no.3 p.481-90, 2004). In order to validate a nonthermal plasma model using nitrogen in a ferroelectric packed-bed reactor, the number density of the excited nitrogen molecules has been investigated by spectroscopic measurements. Experiments were conducted at applied voltages from 0 to 20 kV, 60 Hz and gas flow rates from 1 to 5 L/min in pure nitrogen gas. The results show that the number density for excited N₂ molecules increases with increasing applied voltage and dielectric constant and agrees qualitatively with the numerical modeling results at lower applied voltage. The vibrational temperature of the C³Π_u (v´) state of N₂ has been calculated from the light intensity emitted by the 2nd positive band. The vibrational temperature decreases with increasing gas flow rate and no significant effects of the applied voltage and dielectric constant were observed.