Double laminar and turbulent meteor trails observed in space and simulated in the laboratory

摘要

One of nature's most interesting and beautiful sights is meteor trails that are visible to the naked eye. The first published sketches of trails appeared in 1869 after the Leonids storm of 1868. One of the perplexing features of these trails is that very often they are double trails and seldom triple or quadruple, which rules out breaking up or fractioning as a source. The original observations were visual and reproduced in artwork. The photographs used now reveal the accuracy of the original 1868 drawings. Since 1907, scientific explanations have ruled out physical breakup as a source. The long-standing explanation by Trowbridge (1907) has also been ruled out using modern cameras, and several new explanations have been proposed. Here we modify the explanation by Zinn and Drummond (2005), who modeled the event as an explosion followed by buoyancy, and instead, explain the effect by showing that the trails are severely convectively unstable, leading to the vortices proposed by these authors. This idea is supported by lidar-based measurements of the temperature gradient in the trail. We also show laboratory experiments that are remarkably similar to the meteor trails in appearance, although we argue that buoyancy is not the effect in the natural case. Key Points Meteor trails mainly appear as double trails, seldom as triple or quadruple The trails are severely unstable convectively, leading to vortices Joint observation, simulation, and lab experiments solve the double trail issue