Effective streamer discharge control by tailored nanosecond-pulsed high-voltage waveforms

T Huiskamp,J J Van Oorschot,M Azizi,H Höft,C Ton

doi:10.1088/1361-6463/ac2969

Abstract

In this paper we present our solid-state nanosecond pulse source (the solid-state impedance-matched Marx generator) which can generate arbitrary waveforms and which can be used for pulsed discharge generation. The purpose of the development of such a generator is twofold: by being able to change the waveform at will, we aim to control the discharge generated by such pulses very precisely which can be very useful for plasma applications, but also for more fundamental studies. In the presented study, we applied the arbitrary-waveform pulse source for streamer discharge generation in a cylinder-wire-like arrangement and used the arbitrary-waveform capability to change the rise time (in our experiments we used 6.8–26.2 ns) of unipolar positive pulses with 6-10 kV amplitude and 80 ns duration. Additionally, we introduced variations of a step in the rising edge of the waveform. We performed measurements both in air and nitrogen to electrically characterize the discharge while analyzing the streamer propagation in the plasma reactor with intensified charge-coupled device imaging and measured ozone generation (in air). The results show that we can indeed control the propagation of the streamer discharge with the stepped waveform, but that the rise-time variation has little effect on the streamer propagation in our system. However, the streamer velocity and structure differs significantly comparing discharges in nitrogen and air for the same applied voltage waveform. Additionally, for some of the stepped waveforms we found a slight increase of the ozone yield for air at low overall energy densities.

Highlights

Non-thermal plasmas are efficient in producing highly reactive radical species and energetic photons [1, 2] and have been used for industrial and environmental applications for more than 100 years [1, 3]
In this paper we present our solid-state nanosecond pulse source which can generate arbitrary waveforms and which can be used for pulsed discharge generation
Researchers have noted that the pulse duration and the rise time of the applied high-voltage pulse have a significant influence on the radical yield of the transient plasmas generated with these pulses; shorter pulses result in higher yields [14,15,16,17, 21]

Summary

Introduction

Non-thermal plasmas are efficient in producing highly reactive radical species and energetic photons [1, 2] and have been used for industrial and environmental applications for more than 100 years [1, 3]. These transient plasmas can be effectively used for water decontamination, air purification, surface modification, sterilization and other applications [1, 4, 5]. It is known that the shape of rising slope of the applied high-voltage pulse has direct consequences on the streamer breakdown, as shown e.g. for air [24] and for pure nitrogen [25] at atmospheric pressure

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