Protective cloak: A new layer to Earth's protective magnetosphere has been discovered, shedding light on the origin of its particles.
Credit: Wikimedia
SYDNEY: The discovery of a new layer of the invisible bubble surrounding Earth sheds further light on this magnetic shield which keeps us safe from dangerous solar storms.
The newly discovered 'warm plasma cloak' forms the sixth known part of the Earth's protective region of charged particles and magnetic fields, called the magnetosphere.
New and old yield success
"We have recognised all the other regions for a long time, but the plasma cloak was a fuzzy thing in the background which we didn't have enough information about to make it stand out," said Charles Chappell of Vanderbilt University in in the U.S. city of Nashville, Tennessee. "[But] when we got enough pieces, there it was!"
Chapell led a team of space scientists who report the finding in the Journal of Geophysical Research.
The magnetosphere was first discovered in 1958; six times the size of Earth on the side of Earth facing the Sun, it surrounds our planet then trails off for millions of kilometres behind us. It acts as a crucial shield against the bombardment of energetic particles streaming off the Sun's surface, and can also affect magnetic fields on Earth.
Chapell's team made measurements of the magnetosphere using data from the NASA Polar satellite, combined with measurements taken from four other satellites over the past 30 years. New advances in satellite instrumentation and the amalgamation of new and old data was what revealed the new region to the researchers, he said.
Not so sunny
The discovery adds to the understanding of the form and origin of the different electrically charged particles surrounding the Earth in space.
Fundamentally, Chappell said, the discovery suggests that much of the magnetosphere had its genesis in the Earth's ionosphere - the top layer of the atmosphere and bottom layer of the magnetosphere - rather than in the Sun, as previously thought.
"Thirty years ago, the conventional wisdom was that all these particles came from solar wind. Today, most people think that a large percentage of these particles come from Earth's [own] atmosphere."
The finding of the warm plasma cloak helps explain how atmospheric particles from the Earth's poles feed into the magnetosphere through a 'natural cycle' involving energisation by solar winds.
