Helicopter pilots are familiar with a phenomenon which occurs during dusty landings, when the tips of the rotor blades strike tiny dust particles, igniting a charge of static electricity that lights up the tips of the rotor disc, almost like a halo, as described by former Green Beret and war reporter extrordinaire Michael Yon.
The effect is particularly prevalent under night-vision goggles, but even to the naked eye, it's still visible on some nights. It's quite an eerie glow, and as of yet, has no name to describe it. Indeed, it's not even present in the Army's Field Manual 1-230, the manual which describes aerodynamics. Fortunately, Michael Yon has proposed the name "Kopp-Etchells Effect", named for a US Army Ranger and a British Fusileer who both perished in Afghanistan. I think it's a fitting name for the halo effect.
Drop by Michael Yon's website for a spectacular series of photographs of Chinooks in action in Afghanistan.
(Photo by Michael Yon)
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