Published on December 19th, 2012 | by James Ayre
Solar Wind, Space Turbulence Measured For The First Time
Researchers from the University of Iowa have directly measured space turbulence in the lab for the first time.
“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,” says Gregory Howes, assistant professor of physics and astronomy at the UI and lead author of the paper being published December 17th in the journal Physical Review Letters, of the American Physical Society. “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.”
He adds: “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.”
The most well understood source of space winds are coronal mass ejections, or CMEs. “These solar-powered winds can adversely affect satellite communications, air travel and the electric power grid. On the positive side, solar storms also can also lead to mesmerizing auroras at the north and south poles on Earth.”
“Howes notes that unlike gusts of wind on the surface of Earth, turbulent motions in space and astrophysical systems are governed by Alfven waves, which are traveling disturbances of the plasma and magnetic field. Nonlinear interactions between Alfven waves traveling up and down the magnetic field — such as two magnetic waves colliding to create a third wave — are a fundamental building block of plasma turbulence, and modern theories of astrophysical turbulence are based on this underlying concept.”
“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.
Source: University of Iowa
Image Credits: NASA