Lightning Step Leader and Return Stroke Spectra at 100,000 fps
Abstract
A fundamental understanding of lightning can be inferred from the spectral emissions resulting from the leader and return stroke channels. We examine events recorded at 00:58:07 on 19 July 2015 and 06:44:24 on 23 July 2017, both at Langmuir Laboratory. Analysis of both events is supplemented by data from the Lightning Mapping Array at Langmuir. The 00:58:07 event spectra was recorded using a 100 line per mm grating in front of a Phantom V2010 camera with an 85mm (9o FOV) Nikon lens recording at 100,000 frames per second. Coarse resolution spectra (approximately 5 nm resolution) are produced from approximately 400 nm to 800 nm for each frame. We analyze several nitrogen and oxygen lines to understand step leader temperature behavior between cloud and ground. The 06:44:24 event spectra was recorded using a 300 line per mm grating (approximately 1.5 nm resolution) in front of a Phantom V2010 camera with an 50mm (32o FOV) Nikon lens also recording at 100,000 frames per second. Two ionized atomic nitrogen lines at 502 nm and 569 nm appear upon attachment and disappear as the return stroke travels from ground to cloud in approximately 5 frames. We analyze these lines to understand initial return stroke temperature and species behavior.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMAE23B2485H
- Keywords:
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- 3304 Atmospheric electricity;
- ATMOSPHERIC PROCESSES;
- 3324 Lightning;
- ATMOSPHERIC PROCESSES;
- 3360 Remote sensing;
- ATMOSPHERIC PROCESSES;
- 3394 Instruments and techniques;
- ATMOSPHERIC PROCESSES