Plasma Arc Processes in Thermal Systems

Plasma arc processes involve high-temperature ionised gas discharges that deliver concentrated thermal energy within engineered systems. Such processes are harnessed in a broad range of industrial applications, from thermal spraying and waste treatment to nanopowder synthesis and metallurgical refining. Central to these technologies are plasma torches—devices that maintain a stable arc between electrodes, typically under argon, nitrogen or air atmospheres. The interaction of electrical, thermal and fluid dynamics governs arc stability, enthalpy transfer and mass transport. Electrode phenomena, including heat flux, sheath formation and material erosion, critically influence operational longevity and process control. Advances in modelling have enabled detailed simulation of plasma jets, capturing turbulence, electromagnetic fields and non-equilibrium effects. Thermal management strategies, such as cascaded-anode designs and modulation of gas flow, allow precise tailoring of particle dwell time and temperature profiles. Research increasingly emphasises non-equilibrium plasma regimes, where decoupled electron and heavy-particle temperatures yield novel reaction pathways. Looking forward, integrated experimental and computational studies aim to enhance energy efficiency, reduce electrode wear and expand the technological reach of plasma arc systems in manufacturing and environmental remediation.

Research from Nature Portfolio

Recent studies have elucidated the role of non-equilibrium mechanisms in atmospheric-pressure plasma arcs, demonstrating that synergistic interactions among mass, momentum and energy transfer processes shape the transition between hot and cold equilibrium regions. A combined fluid and sheath model reveals how spatial variations in electron-to-heavy-particle temperature ratios drive self-consistent plasma characteristics, with implications for controlling particle-energy transport. This foundational work provides a framework for predicting and optimising non-equilibrium behaviours in diverse low-temperature arc applications.

Plasma Arc Processes in Thermal Systems publication trend

The graph below shows the total number of articles in plasma arc processes in thermal systems across all publications each year (not limited to Nature Index journals).

Technical terms

Plasma arc: A sustained electrical discharge through gas, producing high-temperature ionised species that conduct current. Thermal plasma: A plasma state in which electrons and heavy particles attain near thermal equilibrium, characterised by elevated enthalpy levels. Non-equilibrium plasma: A plasma in which different species exhibit distinct temperatures, leading to decoupled energy distributions. Electrode sheath: A boundary region adjacent to the electrode surface where electric fields and space charge alter plasma properties. Arc attachment: The mode and location at which a plasma arc contacts an electrode, affecting heat flux and electrode erosion. Cascaded-anode plasma torch: A torch design employing multiple anode segments or inserts to stabilise the arc and control plasma enthalpy distribution.

References

1. Non-equilibrium synergistic effects in atmospheric pressure plasmas. Scientific Reports (2018).
2. Computational study of the effect of the number of splitter plates considering blow-out coil voltage in arc chamber of moulded case circuit breaker. Results in Engineering (2024).
3. Development of an arc root model for studying the electrode vaporization and its influence on arc dynamics. AIP Advances (2020).
4. Predicted Anode Arc Attachment by LTE (Local Thermodynamic Equilibrium) and 2-T (Two-Temperature) Arc Models in a Cascaded-Anode DC Plasma Spray Torch. Journal of Thermal Spray Technology (2021).