Eur. Phys. J. D (2013) 67: 133
https://doi.org/10.1140/epjd/e2013-30514-y

Regular Article

Modelling of discharge in a high-flow microwave plasma source (MPS)

¹ Centre for Plasma and Laser Engineering, Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Gdańsk, Poland
² Department of Marine Electronics, Gdynia Maritime University, Gdynia, Poland

^a e-mail: helena@imp.gda.pl

Received: 18 August 2012
Received in final form: 22 February 2013
Published online: 9 July 2013

Abstract

Self-consistent numerical calculations are performed on a microwave sustained discharge in argon at atmospheric pressure. Very high gas flow rates (typically 120 L/min) are considered. Furthermore, in a discharge tube with a diameter of 26 mm i.d., which is at least twice as large as those currently utilized at 2.45 GHz, according to our calculations, the device nonetheless ensures good impedance matching, as required for an efficient gas processing. Output values of the calculations in the 1 to 6 kW power range are the radial and axial distributions of gas and electron temperature as well as electron density. The specific features that are observed are the fact that: (i) the discharge is not filamentary although the large diameter of the discharge tube favours such a phenomenon when using such a high field frequency and lower gas flow rates; (ii) the occurrence of a minimum value (a hole) of gas temperature and electron density on the tube axis, with the swirling of the gas flow being suggested to improve the uniformity of the discharge parameters, hence the efficiency of a given process.