There’s a sort of radio wave that bangs its way around Earth, knocking around electrons in the plasma fields of loose ions surrounding our planet and sending strange tones to radio detectors. It’s called a „whistler.“ And now, scientists have observed bursts like this in more detail than ever before.
By Rafi Letzter | SPACE.com
Whistlers, typically created during certain lightning strikes, usually travel along Earth’s magnetic-field lines. Humans first detected them more than a century ago, thanks to their ability to make a „whistling“ sound (really more like a ghostly recording of laser blasts in a „Star Wars“ movie) when picked up by a radio receiver. Yesterday (Aug. 14), researchers from the University of California, Los Angeles reported that they’ve produced whistlers in a plasma — a very electrically active, difficult-to-control, gas-like state of matter — in their laboratory, and observed their shapes.
When scientists studied whistlers in the past, they typically relied on data from a handful of widely spaced radio receivers distributed all over the planet. That sort of data is useful but is also incomplete. It tells researchers only so much about how the waves form, how they’re shaped and how different kinds of ambient magnetic fields in the atmosphere influence them. (Detections of whistlers near Jupiter back in 1979 were also the first evidence scientists had that the giant planet has lightning storms like those on Earth.) [Electric Earth: Stunning Images of Lightning]
In this smaller-scale study, the researchers were able to control both the magnetic-field lines of the plasma and the whistlers themselves, which they created with a magnetic device.