Electrification of heat production is vital for a transition to a low-carbon economy. Current electric heating technologies are not well adapted to very high temperature processes (>800 K), limiting the viability of decarbonisation of industries such as steelmaking and cement production. Radio-Frequency inductively-coupled plasma (RF-ICP) torches show potential as electrically-driven sources of high-temperature process heat. In this research, a 1kW RF-ICP device was developed for the generation of near-thermal plasma in nitrogen gas, employing a 27.12 MHz AC power supply and a reverse vortex flow regime. The thermal behaviour and plasma parameters of the device are characterised for a constant input power of 950W, with gas flows rates of 2.5-12.5 slpm and discharge pressures of 3-300 Torr. Optical Emission Spectrometry (OES) is used to determine the rotational and vibrational temperatures of the N₂(C) and N₂⁺(B) metastable states from spectra captured in the plasma source and expelled plume.

In this presentation, the development of the device is outlined and the design choices made to optimise for gas heating, including the driving frequency and use of nitrogen feed gas, are discussed. Key findings from characterisation experiments are reported. The sensitivity of gas temperature and electron density on feed gas flow rate and ambient discharge pressure is explored. Finally, measurements of a time-varying oscillation likely caused by fluctuation in electron density are presented and possible production mechanisms are evaluated.