Maher A. Dayeh, Ph.D., is a senior research scientist in the Space Science and Engineering Division. He has more than 12 years of research experience spanning a range of topics including solar, heliospheric, magnetospheric, and planetary science, as well as the design and development of atmospheric and space instrumentation. He also has studied the physics of lightning.
Photo courtesy of UF/FIT ICLRT
Photo courtesy of UF/FIT ICLRT
Lightning and the thunder that accompanies it are among the most spectacular yet familiar visual and auditory displays in nature. Describing a thunderstorm’s terrifying booms, blinding flashes, and deadly electrical discharges invites superlatives, and not without reason. Lightning strikes the Earth millions of times each day, all over the world. In the U.S. alone, it kills about 100 people each year and injures 1,000 more. It can cause power outages, fires, and plane crashes, amounting to tens of millions of dollars in damages annually. It even happens in space. Lightning has been observed on Jupiter, Venus, Saturn, and Titan. For a multitude of reasons, it’s important for an increasingly technologydriven world to understand exactly what makes lightning happen — and where, and when.
For all the dazzle and danger of a thunderstorm, lightning and thunder remain poorly understood by scientists. Notwithstanding Benjamin Franklin’s legendary (and lucky) kite-flying experiment, studying lightning in nature is complicated and dangerous. Also, because individual lightning strikes are unpredictable, it is impractical to build an instrument array big and close enough to observe and measure the exact conditions that trigger lightning in a cloud, or the path by which it propagates through the air. In the past two decades, advances in instrumentation and remote sensing — and, importantly, the ability to artificially trigger lightning — have significantly enhanced scientific understanding of lightning physics. Scientists now know lightning is associated with high-energy processes that span vast scales and can be observed in different forms, including
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By Maher A. Dayeh, Ph.D.
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SwRI scientists have captured the first images of thunder created by rocket-triggered lightning
SwRI scientists compared long-exposure optical photographs of two different triggered lightning events (top) with acoustically imaged profiles of the discharge channel (below), corrected for sound speed propagation and atmospheric absorption effects. The apparent tilt of the lightning bolt in the left photo is also seen in the acoustic image.
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Technology Today • Fall 2015
