Understanding VHF Intense Processes in Lightning
Abstract
This project concerns the lightning electromagnetic emissions in the very high frequency band (VHF, 30-300 megahertz) of the radio frequency (RF) spectrum. This band is widely used for air traffic control and communications systems, such as ground-to-aircraft and aircraft-to-aircraft communications. Lightning VHF emissions with their very large amplitude are a serious hazard to RF systems within the line-of-sight distance. It is therefore important to study their characteristics and generation processes for personnel safety and assets operation of the U.S. Air Force. The objective of the project is to understand how various lightning processes generate strong VHF emissions. It is believed that small-scale streamer discharges in lightning are the ultimate source and that VHF-intense lightning processes may contain tens of millions of them. It is poorly understood how such a large number of streamers collectively generate VHF emissions with varying characteristics and how VHF emission properties are related to thundercloud electrical conditions. This project will first investigate the properties of individual streamers and their VHF emissions using an advanced plasma discharge simulation code and then further develop a numerical model of a system of streamers for evaluating their collective electromagnetic properties. Finally, an interferometric image simulation model will be improved to better predict lightning VHF interferometer observations of potential source models. This comprehensive approach will significantly advance our understanding of VHF-intense lightning processes, as well as our ability to correctly interpret VHF observations of lightning. Because the proposed research investigates the fundamental aspects of VHF production in lightning, it will generate significant impact across many actively-pursued lightning research subjects. Furthermore, it can shape the lightning VHF observational efforts of research groups across the world, impacting the design and operation configuration of the VHF instrument.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 06, 2025
- Source ID
- FA95502410124
Entities
People
- Ningyu Liu
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University System of New Hampshire