Understanding Lightning from the Lab: Initiation, Propagation, and X-ray Emissions

Introduction

Despite the huge impact of lightning, its fundamental properties are still very poorly understood. With this project, I want to build an infrastructure of carefully designed laboratory experiments in a novel physical regime that will provide the conditions required to understand lightning phenomena. I will use this to answer some of the major open questions in lightning and high voltage discharge research.

Research Objectives

I will provide major scientific breakthroughs to answer the questions on:

1. How lightning is initiated
2. How lightning propagates by so-called leaders
3. How these leaders emit energetic radiation (X-rays)

The experiments will be complemented by dedicated numerical simulations for the best interpretation.

Lightning Initiation

Initiation of lightning within thunderclouds involves a complex, yet not understood interplay between electric fields, ice particles, charges, and cosmic rays. I will have ice-like particles fall through varying electric fields in the novel discharge chamber and observe when discharges form and when they are strong enough to initiate lightning.

Lightning Propagation

Once initiated, lightning propagates through so-called leader discharges, but the exact mechanism has only been hypothesized. I want to understand how this is controlled by streamer discharges around it.

Radiation Emission

During inception and propagation, lightning emits X-rays and other energetic radiation with energies far above expected electron energies. I will pinpoint the location and mechanism of such emissions with high reproducibility.

Unique Experimental Setup

The experiments will be unique in the world, due to the large discharge chamber, its highly controlled atmosphere, and its accompanying pulse source surpassing existing experiments by orders in voltage risetime and amplitude. This will expose new physical phenomena and thereby lead to great insights and uses:

• For the lightning community: validation of simulations and theories and understanding of lightning radio emissions
• For high voltage engineers: tools to improve their devices