Particles from space provide insights into charges in thunderclouds
High-speed particles from space are helping to unravel a high-voltage mystery in the clouds.
Astronomers have determined the strength of electric fields in thunderclouds by detecting the radio wave signature of cosmic ray particles striking the atmosphere. Reported April 24 in Physical Review Letters, the research offers insight into the confluence of cloud conditions that leads to lightning strikes, which atmospheric simulations cannot explain. The technique could also validate an intriguing hypothesis that cosmic rays provide the spark that triggers lightning.
Cosmic rays constantly pelt the planet. Occasionally they strike atoms in the atmosphere and generate a cascade of new particles. LOFAR, an observatory based in the Netherlands, tracks these cosmic ray showers with particle detectors and small antennas, which detect radio waves emitted mainly by the shower’s electrons. In fair weather,