Radiation from an equilibrium CO2-N2 plasma in the [250-850 nm] spectral region: I. Experiment

An inductively coupled plasma torch, working at atmospheric pressure, is used to create a CO2-N2 Martian-like plasma (97% CO2-3% N2). The operating frequency and power are 64 MHz and 3 kW, respectively. Spectral measurements covering the [250-850] nm range have been carried inside the induction coil. Spectral profiles of emitting diatomic species have been measured, intensity calibrated, Abel inverted and fitted with a line-by-line code. This has allowed rebuilding the radial temperature profiles of the plasma. A simplified kinetic model has then been developed in order to confirm that chemical equilibrium is reached in this region of the plasma. Then, the plasma chemical composition has been determined utilizing a calculation code based on the Gibbs free energy minimization method. Overall, a complete characterization for the thermal, chemical and radiative properties of the plasma has been achieved in the induction coils region.