Lateral streamers emergence from sprite glows
Abstract
Sprites are high altitude (45-90 km) and filamentary electric discharges made of hundreds of streamers. High-speed observations of sprites report the development of luminous trails in the streamer wake named sprite glows. These sprite glows readily produce upward-sideways streamers, a phenomenon tightly related to the classification of sprites into carrot or column type.
In this work, we use a 3D streamer model to investigate the launch of lateral streamers from sprite glows. We show from the onset of the glow region and, for the first time, how several negative lateral streamers emerge close to the lower boundary of the glow, where negative charge gets trapped and the lateral electric field is high enough. We also discuss how these lateral streamers affect the main streamer channel. Essentially, the lateral streamer acts as a cut-off for the current in the glow, leading to an optical deactivation of some regions of the glow. Finally, our results also reveal the formation of a region in the lateral streamer that mimics the features of the glow in the main streamer channel. This new region accumulates positive charge in its upper boundary and therefore it could be the origin of positive downwards streamers. We suggest this as a possible mechanism for angel sprites. However, observations and our results point out that angel sprites must take place in a very constrained parameter space.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMAE31B3108M
- Keywords:
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- 3304 Atmospheric electricity;
- ATMOSPHERIC PROCESSES;
- 3324 Lightning;
- ATMOSPHERIC PROCESSES;
- 3394 Instruments and techniques;
- ATMOSPHERIC PROCESSES