Monday, April 22, 2013

NASA WIND Spacecraft captures image of Magnetosphere

A complex system of charged particles from the Sun and magnetic structures piles up in front of the Earth. 

Scientists now hope to better understand this area in front of the Bow shock, known as the foreshock, as it can help explain how energy from the rest of space makes its way into the magnetosphere.

Earth is seen as a tiny speck surrounded by an enormous magnetic 'bubble' surging through space in this image released by Nasa.

Far from the usual view of a blue and green globe spinning peacefully in the solar system, the dramatic picture illustrates the speed and energy of the magnetosphere that surrounds Earth as it moves around the sun.

Scientists studying data collected by Nasa's WIND spacecraft have used it to create a more detailed snapshot of the way solar particles streaming in from the sun bounce off the bubble.

Nasa researchers have been examining data from WIND - which travelled through the region at the boundary of the magnetosphere 17 times between 1998 and 2002 - to find out more about the 'dramatic' changing conditions within the complex, turbulent system called the foreshock.

As the magnetosphere ploughs through space, it sets up a standing bow wave or bow shock - much like that in front of a moving ship. The foreshock lies just in front of this bow wave.

Conditions in the foreshock change in response to solar particles streaming in from the sun, moving magnetic fields and a host of waves sweeping through the region, according to Nasa.

Lynn Wilson, deputy project scientist for Wind at Nasa's Goddard Space Flight Center in Greenbelt, Maryland, explained how 'cool squiggles' she stumbled upon in the data 'turned out to be a special kind of magnetic pulsations called short large amplitude magnetic structures, which we call SLAMS for short'.

Studying the region around these 'rogue waves' and how they propagate may help to establish what accelerates narrow jets of charged particles back out into space and away from Earth.

David Sibeck
David Sibeck, a space scientist at Goddard who is co-author of the paper, explained how space weather events that seem small can have 'profound effects downstream', from affecting GPS satellites to prompting solar storms.

'The front of the magnetosphere is right in the line between sun and Earth, so it's a crucial place to understand which small things can lead to big results,' he said.

'What happens to Earth's magnetic field depends on what's happening here at the front of the bow shock and what's happening there is dramatic.

'It's going to affect how much energy moves into the magnetosphere. Once inside the magnetosphere, it can create powerful solar storms and impact communications and GPS satellites that we depend on daily.'

According to Nasa: 'The more we know about what happens in the frothy, turbulent area in front of Earth, the more we know about how the solar wind and other material bursting off the sun may be able to penetrate into near Earth-space.'

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