Investigations on pulsed, dielectric barrier discharges in multi-filament arrangements

• Applicant: Dr. Hans Höft
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 408777255

• Final Report Year: 2023

Final Report Abstract

The project focused on investigating dielectric barrier discharges (DBDs), commonly used for generating reactive species in non-thermal atmospheric pressure plasmas. DBDs in air-like gas mixtures operate in the filamentary mode, which is characterised by transient discharge channels called filaments. Previous research primarily focused on single-filament DBD arrangements, but this project aimed to upscale the findings to multi-filament configurations. Experimental investigations successfully characterised a onedimensional multi-filament arrangement. It was determined that approximately 15 filaments formed within 2 ns in a 1 mm gap with a lateral dimension of 10 mm. A comparison between results for the multi-filament arrangement and the single-filament arrangement revealed that various discharge characteristics, such as electrical energy, transferred charge, and current peaks, scaled directly with the number of filaments during pulsed operation. The breakdown and development of multi-filament DBDs could be precisely controlled by manipulating the width of the high-voltage (HV) pulse, employing the concept of pre-ionisation like for single-filament DBDs. Furthermore, a comparison between sinusoidal- and pulsed-operated DBDs uncovered differences in discharge inception and development, with staggered lateral discharge inception occurring over microseconds for sine-driven DBDs. Additionally, the exploration of double-filament arrangements revealed significant interactions between the filaments in terms of discharge inception, particularly during pulsed operation, influenced by the inter-filament distance. These findings provide critical insights for optimising arrangements for filamentary DBDs, especially with respect to the electric circuit. In summary, the project successfully demonstrated that most results obtained for single-filament DBDs can be directly applied to multi-filament arrangements. The ability to control discharges by varying the HV pulse width holds promise for practical multi-filament reactors. The transferability of results obtained for single-filament DBDs to multi-filament arrangements highlights the robustness and applicability of the acquired knowledge. The project’s accomplishments significantly advanced the understanding of DBDs, with implications for enhancing plasma-based technologies in chemical processing, environmental remediation, and biomedical applications. By leveraging the knowledge gained from single-filament DBDs, researchers can effectively manipulate and control more complex multi-filament DBD arrangements, which can open up new possibilities in various fields of plasma science and technology.

Publications

• Double-propagation mode in short-gap spark discharges driven by HV pulses with sub-ns rise time. Plasma Sources Science and Technology, 29(8), 085002.
  Höft, H.; Becker, M. M.; Kolb, J. F. & Huiskamp, T.
  
• Breakdown and development of sub-ns pulsed sparks in short gaps Invited talk at IEEE PPC/SOFE conference (2021)
  H. Hoft, M.M. Becker, J.F. Kolb & T. Huiskamp
  
• Effective streamer discharge control by tailored nanosecond-pulsed high-voltage waveforms. Journal of Physics D: Applied Physics, 55(2), 024001.
  Huiskamp, T.; Ton, C.; Azizi, M.; van Oorschot, J. J. & Höft, H.
  
• From single- to multi-filament arrangements for pulsed dielectric barrier discharges Talk at DPG conference (2021)
  H. Hoft, M. Kettlitz & R. Brandenburg
  
• Images to Excite and Inspire! - Visualisation of multi-filament DBDs International Low Temperature Plasma Community Newsletter 20, 25th January 2022
  H. Hoft
  
• Impact of dielectric-covered electrode proximity on streamer propagation in pulsed-driven dielectric barrier discharges Talk at HAKONE XVII (2022)
  H. Hoft, J.R. Wubs, M. Kettlitz, M.M. Becker, A. P. Jovanovic & K.-D. Weltmann
  
• Impact of the electrode proximity on the streamer breakdown and development of pulsed dielectric barrier discharges. Plasma Sources Science and Technology, 31(3), 035006.
  Wubs, J. R.; Höft, H.; Kettlitz, M.; Becker, M. M. & Weltmann, K.-D.
  
• Investigations on the impact of electrode proximity on streamer breakdown and development of pulsed dielectric barrier discharges Talk at DPG conference (2022)
  H. Hoft, J.R. Wubs, M. Kettlitz, M.M. Becker & R. Brandenburg
  
• Upscaling from single- to multi-filament dielectric barrier discharges in pulsed operation. Journal of Physics D: Applied Physics, 55(42), 424003.
  Höft, H.; Becker, M. M.; Kettlitz, M. & Brandenburg, R.
  
• Understanding single-filament barrier discharges as a keystone for optimised multi-filament reactors Invited Talk at PT20 (2023)
  H. Hoft, M. M. Becker, M. Kettlitz, M. Schmidt & R. Brandenburg