Optical emission of nitrogen in an electron beam sustained hybrid discharge

Abstract

Electron beam sustained hybrid discharges are plasma sources that promote a high degree of non-equilibrium, which is a promising feature for effectively stimulating chemical reactions. Here, we describe the quantification of emission from a 54 Pa N2 discharge sustained by an electron beam (EB) (U b = 25 kV, I b = 1–5 mA) superimposed to an inductive coupled plasma (ICP). The optical emission from the first negative system (FNS) and the second positive system (SPS) is quantified as a function of the EB and ICP input power. The relative emission from the FNS and SPS is compared to the relative production rates from EB excitation. The spectral changes arising due to varying the applying additional plasma power via the ICP suggest secondary plasma electron excitation processes. Under assumption of the Corona model, the relative population of the vibrational levels of the excited state N2C(3Πu (v’ = 0–2)) is calculated and compared to previously obtained results. The ICP source mainly results in higher SPS emission and has a mild influence on the FNS signal intensity. These results show the potential to control ionization and plasma excitation processes independently via the EB and ICP, respectively.