![]() ![]() Often, they happen in conjunction with “Emissions of Light and Very Low Frequency Perturbations due to Electromagnetic Pulse Sources,” also known as ELVES, which are enormous halos of light that shoot outward to cover up to 500 kilometers in a millisecond. They ionize the nitrogen in our atmosphere, causing a red glow. ![]() The most common are sprites, tall and highly structured bursts of light that appear above thunderstorms. Using a relatively simple camera and radio dish, Ashcraft has seen a whole bestiary of odd TLE phenomena. ![]() "One of the neatest things about TLEs is that first image in 1989 was just a serendipitous capture," said amateur radio astronomer Thomas Ashcraft, who has been photographing the events for several years. They found dozens more examples of TLEs, and later scientists have been recording them ever since. Hearing of the finding, NASA officials immediately ordered a review of video tapes taken from the space shuttle that looked at lightning events on Earth. Winckler saw brilliant columns of light extending from the tops of storm clouds. Replaying the tape later on, Professor John R. The first image of a TLE was captured accidentally in 1989 when a University of Minnesota professor aimed a low-light TV camera at the sky to film a rocket launch. Pilots had reported enigmatic bright flashes throughout the 20th century, but their anecdotal evidence didn't amount to proof. These spectacles are relatively new to science. There, the thin air interacts with strong electrical fields to ionize molecules and create arcing plasmas. They occur between 50 to 100 kilometers above the ground, a long-ignored area of the atmosphere that is too high for aircraft but too low for satellites to investigate. These mysterious phenomena are known as Transient Luminous Events (TLEs), and are usually invisible to the naked eye because they happen on millisecond timescales, too fast to be seen. A past observation and our ensuing analyses both indicate that the ELVES occurrence rate and, thus, their energy deposition rate in the upper atmosphere should be higher.In the blink of an eye, an enormous bright red light flashes above a thundercloud, spreading energetic branches that extend five times taller than Mount Everest and look like jellyfish tendrils and angel's wings. However, the global occurrence and energy rates for ELVEs are likely the lower‐bound values. After factoring in the occurrence rates, in each minute sprites, halos, and ELVEs deliver 22, 52, and 1370 MJs of troposphere energy to the upper atmosphere, which are also higher than those reported in Kuo et al. From analyzing ISUAL TLE events without lightning emission contamination, the average deposited energy in the upper atmosphere by sprites, halos, and ELVEs was found to be 22, 14, and 19 MJ per event, respectively. Using these updated TLE rates, the free electron content over an ELVE hot zone is estimated to be elevated by more than 10%. , the global occurrence rates for ELVEs and halos are higher due to the adoption of different correction factors. Comparing with the results from the first three years of the ISUAL experiment reported by Chen et al. The global TLE occurrence rates are inferred to be 72, 3.7, and ∼1 events / minute, respectively, for ELVEs, halos, and sprites. However, nearly 60% of ELVEs occurred over the ocean, a feature indicating that the high peak current lightning is more abundant over the ocean. The distribution of sprites and halos closely resemble that of the cloud‐to‐ground lightning. Based on the first four years of the ISUAL (Imager of Sprites and Upper Atmospheric Lightning) experiment onboard the FORMOSAT‐2 satellite, ELVEs are found to be the most abundant type (∼80%) of TLEs (transient luminous events), whereas sprites and halos only combine to account for ∼20%. ![]()
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