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

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.

Characteristics of high-repetition-rate bipolar pulse DBD under various electrical conditions in atmospheric-pressure air

“…Ozone generation, along with voltage, was undoubtedly dominant in this experimental study at 20 kHz. This has been found in other research findings [65,66]. The graph of ozone concentration according to the PRR is not monotonous.…”

Fast and Flexible, Arbitrary Waveform, 20-kV, Solid-State, Impedance-Matched Marx Generator

“…The impedancematched structure can be used for both the Marx and LTD with similar performance [28], and we chose to use the Marx circuit as it does not depend on magnetic cores (which could saturate at longer pulse lengths [21]). The concept and a first prototype was presented in [26] and a follow-up prototype was used for streamer discharge control with flexible pulses in [20]. This article will explain the operation principles of a significantly improved version capable of kHz repetition rate and MW power output.…”

“…In addition, the repetition rate, either continuous or in bursts, has a significant influence on the plasma: when plasma species (e.g., radicals or ionized particles) of a previous pulse are still present, they influence the next pulse [18], [19]. This opens a new area of research to plasma generation [15], [20].…”

Rogowski and D-Dot Sensors for Nanosecond High-Voltage and High-Current Pulse Measurements in Impedance-Matched Pulse Generators

“…The IMG consists of a number of stages (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), where each stage switches 1 kV and several hundred A. Each stage consists of HV capacitors and six 1200-V SiC MOSFETs, combined with diodes (for bypassing the stage).…”