Comparing simulations and experiments of positive streamers in air: steps toward model validation

• Main Authors: Li, Xiaoran, Dijcks, Siebe, Nijdam, Sander, Sun, Anbang, Ebert, Ute, Teunissen, Jannis
• Format: Journal Article
• Language: English
• Published: 07-08-2021
• Subjects: Physics - Plasma Physics
• DOI: 10.48550/arxiv.2106.00409

We compare simulations and experiments of single positive streamer discharges
in air at 100 mbar, aiming towards model validation. Experimentally, streamers
are generated in a plate-plate geometry with a protruding needle. We are able
to capture the complete time evolution of reproducible single-filament
streamers with a ns gate-time camera. A 2D axisymmetric
drift-diffusion-reaction fluid model is used to simulate streamers under
conditions closely matching those of the experiments. Streamer velocities,
radii and light emission profiles are compared between model and experiment.
Good qualitative agreement is observed between the experimental and simulated
optical emission profiles, and for the streamer velocity and radius during the
entire evolution. Quantitatively, the simulated streamer velocity is about 20%
to 30% lower at the same streamer length, and the simulated radius is about 1
mm (20% to 30%) smaller. The effect of various parameters on the agreement
between model and experiment is studied, such as the used transport data, the
background ionization level, the photoionization rate, the gas temperature, the
voltage rise time and the voltage boundary conditions. An increase in gas
temperature due to the 50 Hz experimental repetition frequency could probably
account for some of the observed discrepancies.