Lightning corona Imaging From a radio Telescope

Introduction

We do not understand how lightning in our atmosphere initiates, nor how it develops and propagates after initiation. The fundamental difficulty is that these basic lightning phenomena are driven by the meter-scale dynamics of the low-conductivity plasma that surrounds the lightning channel, known as the corona, but the dynamics of this corona is as-yet unresolved.

Importance of the Lightning Corona

Resolving the structure of the lightning corona and how it develops in time is the holy grail of lightning science. This will reveal:

1. The mechanism behind lightning initiation.
2. The physics behind how lightning channels grow and propagate.
3. Why lightning emits intense flashes of X-ray and gamma ray radiation.

Project Overview

During the LIFT project, I will develop new advanced data processing techniques, including polarization imaging and interferometric beamforming. These techniques will produce meter-scale and nanosecond precise radio-frequency images of lightning activity.

Data Collection

This project will use data collected by the LOw Frequency ARray (LOFAR) radio telescope, which previous work has shown to be the most precise and sensitive lightning interferometer in the world.

Expected Outcomes

The end result of this project will be finely resolved images of lightning corona that are an order-of-magnitude more precise than all previous work. Since it is the coronal plasma that drives most other lightning processes, the impact will be a fundamentally deeper insight into the physics of:

• Lightning initiation.
• Propagation.
• Emission of energetic radiation.

Research Questions

This project aims to resolve long-standing questions, including:

1. How cosmic rays or hydrometers could be involved in lightning initiation.
2. How lightning expands from a single point to a kilometer-scale network.
3. Which key plasma processes allow lightning channels to grow.

Technological Advancements

In addition, the LIFT project will make use of the drastically increased bandwidth and processing power that will be made available during the LOFAR 2.0 upgrade. This will push the observations to even higher spectral and spatial precision.