December 18, 2012
Researchers Get First Direct Evidence Of Turbulence In Outer Space
[ Watch the Video: Measuring Space Tubulence ]
April Flowers for redOrbit.com - Your Universe OnlineWe all know that turbulence exists on Earth, but does it really exist in outer space? And if it does, how would you prove it?
“Turbulence is not restricted to environments here on Earth, but also arises pervasively throughout the solar system and beyond, driving chaotic motions in the ionized gas, or plasma, that fills the universe,” said Gregory Howes, assistant professor of physics and astronomy at the UI. “It is thought to play a key role in heating the atmosphere of the sun, the solar corona, to temperatures of a million degrees Celsius, nearly a thousand times hotter than the surface of the sun."
“Turbulence also regulates the formation of the stars throughout the galaxy, determines the radiation emitted from the super massive black hole at the center of our galaxy and mediates the effects that space weather has on the Earth," Howes noted in a recent statement.
Coronal mass ejections — violent emissions of charged particles from the sun — are one well known source of gusty space winds. Solar-powered winds such as these can adversely affect satellite communications, air travel and the electric power grid. They aren't completely negative, however, they also cause the auroras at the North and South poles.
Turbulence in space, unlike wind gusts on Earth, is governed by Alfven waves, which are traveling disturbances of the plasma and magnetic field. Modern theories of astrophysical turbulence are based on the underlying concept of nonlinear interactions between Alfven waves traveling up and down the magnetic field. Nonlinear interactions – such as two magnetic waves colliding to create a third wave – are a fundamental building block of plasma turbulence.
“We have presented the first experimental measurement in a laboratory plasma of the nonlinear interaction between counter-propagating Alfven waves, the fundamental building block of astrophysical turbulence,” Howes says.