# Pilot system development in metre-scale laboratory discharge

## TL;DR

This study investigates metre-scale laboratory discharges using ns-fast photography, revealing bipolar structures that resemble high-altitude sprites, and proposes a 1D ionization model to explain their development.

## Contribution

The paper introduces a 1D ionization model for laboratory discharges and links observed structures to natural sprites, advancing understanding of discharge phenomena.

## Key findings

- Bipolar structures form near the negative electrode.
- Discharges exhibit features like glowing beads and reconnection.
- The 1D model replicates observed ionization growth features.

## Abstract

The pilot system development in metre-scale negative laboratory discharges is studied with ns-fast photography. The systems appear as bipolar structures in the vicinity of the negative high-voltage electrode. They appear as a result of a single negative streamer propagation and determine further discharge development. Such systems possess features like glowing beads, bipolarity, different brightness of the top and bottom parts, and mutual reconnection. A 1D model of the ionization evolution in the spark gap is proposed. In the process of the nonlinear development of ionization growth, the model shows features similar to those observed. The visual similarities between high-altitude sprites and laboratory pilots are striking and may indicate that they are two manifestations of the same natural phenomenon.