News and Colloquium
Use this page to read about recent news and important events in the NMT Physics Department, and find announcements of upcoming colloquia on a variety of physics topics.
- Upcoming Masters thesis defense by Alex Attanasio of NMT & Langmuir Laboratory "An Electrostatic Model of Fast Breakdown as a system of Streamers", on April 9 at 9 am. More details below.
- The New Mexico Tech Physics Department has been ranked 39th by College Factual out of 263 schools for Physics! Read more about it here.
Speaker: Alex Attanasio
Affiliation: NMT & Langmuir Laboratory
Title: An Electrostatic Model of Fast Breakdown as a system of Streamers
Key insights into the centuries-old question of how lightning is initiated have been found with the recent discovery of fast breakdown (FB), a breakdown process composed of systems positive or negative streamers traveling at 10% the speed of light or faster. An early model of growing streamer systems developed by Griffiths & Phelps (1976) is implemented and used to investigate the electrostatic behavior of streamer system charge growth and its capability of representing FB. This model is improved to match modern streamer physics with parametric descriptions of FB radial development, negative polarity streamers, velocity, and ambient electric field conditions. Supervised machine learning techniques are used alongside the model to reproduce observed narrow bipolar event (NBE) waveforms, produced by some of the most energetic forms of FB, showing a roughly 50% reduction in error compared to the original G&P model. An analytical formula is developed relating the potential difference in a storm cloud and the distance a given case of FB propagates, revealing that at constant altitudes positive FB is easier to initiate than negative FB. Despite this the required potential difference for observed negative FB in higher altitude Florida storms is nearly identical to that needed for positive FB seen at lower altitudes in New Mexico, both needing about 100 MV to travel 500 m. Additionally, it is found that FB enhances the strength of the electric field ahead of it producing regions of dozens to hundreds of MV potential differences which can initiate rebounding FB of the opposite polarity or accelerate runaway electron avalanches that result in terrestrial gamma-ray flashes
Time: Friday 4/9, 9:00 am - 10:00 am Mountain Daylight Time
Topic: Spring 2021 - PHYS-579-01D-Colloquium Link
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