Greek-American UCLA Professor Contributes To Discoveries Explaining Vanishing Electrons

After years of efforts, UCLA researchers have explained the puzzling disappearing act of energetic electrons in Earth’s outer radiation belt, taking one step closer towards understanding and predicting space weather phenomena.

The team of scientists, including Greek-American UCLA Professor Vassilis Angelopoulos, using data collected from a fleet of orbiting spacecraft, discovered that the missing electrons are being swept away from the planet by a tide of solar wind particles during periods of heightened solar activity.

During powerful solar events such as coronal mass ejections, parts of the magnetized outer layers of the sun’s atmosphere crash onto Earth’s magnetic field, triggering geomagnetic storms capable of damaging the electronics of orbiting spacecraft.

These cosmic squalls have a peculiar effect on Earth’s outer radiation belt, a doughnut-shaped region of space filled with electrons so energetic that they move at nearly the speed of light.

“During the onset of a geomagnetic storm, nearly all the electrons trapped within the radiation belt vanish, only to come back with a vengeance a few hours later,” said Vassilis Angelopoulos, a UCLA professor of Earth and space sciences, and IGPP researcher.

Key observational data used in this study was collected by a network of NASA spacecraft known as THEMIS (Time History of Events and Macroscale Interactions during Substorms); Angelopoulos is the principal investigator of the THEMIS mission. Additional information was obtained from two groups of weather satellites called POES (Polar Operational Environmental Satellite) and GOES (Geostationary Operational Environmental Satellite).

Vassilis Angelopoulos was born in 1965 and graduated from the Physics Department of the Aristotle University of Thessaloniki in 1986, obtaining his PhD in Physics from UCLA, with specialization in Space Plasma Physics in 1993, having obtained a scholarship from the Fulbright Foundation.

(Sources: Pathfinder, UCLA Newsroom)


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