Stereo-photography of point-plane streamers in air

TL;DR

This paper introduces stereo-photography techniques to visualize the three-dimensional structure of point-plane streamer discharges in air, providing new insights into their branching angles and spatial configuration.

Contribution

It presents a novel stereo-photographic setup and analysis for 3D visualization of streamer discharges, revealing consistent branching angles regardless of pressure or distance.

Findings

Branching angles are approximately Gaussian with a mean of 43 degrees.

Branching angles do not significantly depend on distance from the needle.

Branching angles are consistent across different gas pressures.

Abstract

Standard photographs of streamer discharges show a two-dimensional projection. We here present stereo-photographic images that resolve their three-dimensional structure. We describe the stereoscopic set-up and evaluation, and we present results for positive streamer discharges in air at 0.2 - 1 bar in a point plane geometry with a gap distance of 14 cm and a voltage pulse of 47 kV. In this case an approximately Gaussian distribution of branching angles of 43 degrees is found; these angles do not significantly depend on the distance from the needle or on the gas pressure.