Monday, December 15, 2008

In time for XMAS - Earth's new warm cloak

Newly discovered, that is.

A team of scientists led by Charles “Rick” Chappell, research professor of physics and director of the Dyer Observatory at Vanderbilt University says their analysis of the measurements of five different satellites reveals the existence of the "warm plasma cloak", a hitherto unknown region of the magnetosphere, that invisible shield of magnetic fields and electrically charged particles that surround and protect Earth from the solar wind.

Published this fall in the space physics section of the Journal of Geophysical Research, Chappell's research reveals a “natural cycle of energization” that accelerates the low-energy ions originating from Earth’s atmosphere up to the higher energy levels characteristic of the different regions in the magnetosphere. This brought the existence of the new region into focus.

So what is it? Says the Vanderbilt news release: "The warm plasma cloak is a tenuous region that starts on the night side of the planet and wraps around the dayside but then gradually fades away on the afternoon side. As a result, it only reaches about three-quarters of the way around the planet.

"It is fed by low-energy charged particles that are lifted into space over Earth’s poles, carried behind the Earth in its magnetic tail but then jerked around 180 degrees by a kink in the magnetic fields that boosts the particles back toward Earth in a region called the plasma sheet."

By the way it wraps around Terra, should it be called a warm toga or a warm lungi or heavens - a warm diaper? - instead of a warm cloak?

Image: Rick Chappell, Vanderbilt University

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