VV(9) - Atmospheric Waves

[David Morris]

http://www.science.nasa.gov/newhome/headlines/ast29dec99_1.htm

The Warp and Woof of a Geomagnetic Storm

New data display shows how energy deposited by the solar wind squeezes 
Earth's magnetosphere

Every now and then, the sun spits out a bubble of ionized gas known as a 
coronal mass ejection or CME. While it's easy to envision a special effect 
worthy of Star Wars, a CME actually carries a fairly weak punch since its 
energy is spread over a large volume of space.

Part of that energy can be concentrated when the CME washes over a large 
object, like the Earth and its invisible shield, the magnetosphere, that is 
generated by the Earth's magnetic field.

"If the Earth happens to be in the way [of a CME], then we're looking to see 
how the aurora responds," said Dr. Jim Spann, a space plasma physicist at 
NASA's Marshall Space Flight Center.

The magnetosphere, populated with ionized gases and electrons, is like an 
invisible shield around the Earth. The Earth's magnetic field forces the 
solar wind to part and slide around it. But at the same time, a gust in the 
solar wind can squeeze the magnetosphere, forcing some of the 
magnetosphere's particles earthward along the magnetic field lines. 
Particles energized enough to burrow as deep as the upper atmosphere 
produces the dazzling aurora borealis and magnetic storms.


_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com