New instrumentation helps scientists better predict space weather (Forwarded)

News Bureau
University of Illinois at Urbana-Champaign
Champaign, Illinois

Contact:
James E. Kloeppel, Physical Sciences Editor
217-244-1073

Released: 12/11/06

New instrumentation helps scientists better predict space weather

CHAMPAIGN, Ill. -- New instrumentation and observing techniques, being
developed by researchers at the University of Illinois at Urbana-Champaign,
are helping scientists better understand and predict space weather.

Space weather can be caused by giant solar flares and coronal mass ejections
from the sun, and can adversely affect life on Earth. Tremendous blasts of
radiation may threaten astronauts, disrupt satellite communication and
navigation systems, and knock out power grids on Earth. Near Earth's
magnetic equator, however, space weather can have dramatic effects even
during quiet solar conditions.

"These storms are among the most explosive events that occur in the
ionosphere, and are an important component of ongoing space weather
research," said Jonathan Makela, a professor of electrical and computer
engineering at Illinois.

"A better understanding of the physical processes responsible for these
storms could improve our ability to forecast space weather," Makela said,
"and lead to better techniques to mitigate its effects."

The ionosphere extends from approximately 100 kilometers to more than 1,000
kilometers above Earth's surface. In this region of the atmosphere, solar
radiation can strip the outer electrons from atoms and molecules of gas.
After sunset, the electrons recombine and give off light, called airglow.
Space weather events at the magnetic equator appear as depletions in the
airglow. As signals at radio wavelengths pass through these turbulent
regions, they scintillate -- much like the twinkling of starlight at optical
wavelengths.

Unlike aurora, which can be seen with the naked eye, airglow near the
magnetic equator is visible only in photographs taken through narrow-band
filters with exposure times of a minute or two.

In August 2006, Makela installed a narrow-field ionospheric airglow imager
at Cerro Tololo Inter-American Observatory, located east of La Serena,
Chile. The imager looks north, parallel to Earth's magnetic field and toward
the magnetic equator. Two GPS scintillation monitors were also installed at
the site, and are used to study ionospheric instabilities at a smaller size
scale.

"The GPS monitors allow us to perform simple interferometric calculations
and derive drift velocities of the perturbations that cause the
scintillations," Makela said. "By measuring power fluctuations in the GPS
signals, we can also correlate the scintillation patterns with the airglow
images."

Makela is also attempting to correlate his airglow images with radar
backscatter observations made with the Jicamarca radar system near Lima,
Peru.

"In this way, we can study the relative roles of the equatorial and local
regions of the ionosphere in the production of scintillation-causing
perturbations," Makela said. "This could then help us better predict space
weather, prepare further safeguards on Earth and in space, and plan more
robust communication and navigation schemes during space weather events."

Makela will describe the instrumentation and present early results, based on
overlapping data from the imager, GPS receivers and Jicamarca radar, at the
American Geophysical Union meeting in San Francisco, Dec. 11-15.

Makela's work in Chile is in collaboration with electrical and computer
engineering professors Paul Kintner at Cornell University and Brent Ledvina
at the Virginia Polytechnic Institute and State University. Illinois
graduate student Ethan Miller is also working on the project.

The National Science Foundation and the U.S. Naval Research Laboratory
funded the research.

Editor's note: To reach Jonathan Makela, call 217-265-9470.