Excitation Temperature in High-Power Nitrogen Microwave-Induced Plasma at Atmospheric Pressure

Excitation temperature, rotational temperature, and electron density were obtained for a high-power (1-kW) microwave-induced nitrogen plasma (N₂ MIP) at atmospheric pressure generated by an Okamoto cavity. With 1 kW input microwave power, an excitation temperature of 5500 K, a rotational temperature of 5000 K, and an electron density in the 10¹³ range were measured. Excitation and rotational temperatures were much closer than is the case with the commonly used argon inductively coupled plasma, suggesting that this N₂ MIP is closer to local thermodynamic equilibrium (thermal).