Researchers identify zebra-like stripes of plasma in a patch of space
Since the early 1970s, orbiting satellites have picked up on noise-like plasma waves very close to the Earth’s magnetic field equator. This “equatorial noise,” as it was then named, seemed to be an unruly mess of electric and magnetic fields oscillating at different frequencies in the form of plasma waves. Now a team from MIT, the University of California at Los Angeles, the University of Sheffield, and elsewhere has detected a remarkably orderly pattern amid the noise. In a region of space about 12,000 miles from Earth’s surface, two spacecraft separated by a narrow patch of space — about as wide as Rhode Island — identified a region where the tangle of plasma waves gives way to a very regular structure. The scientists detected the invisible structure using a spectrogram — a visual representation of the spectrum of frequencies in space. Through this lens, they observed a stack of 13 equally spaced,...