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Frontiers
Solar Storm Disruptions: More Are on the Way
September 1996
In November 1993, a giant bubble of gas erupted
from the sun. Rocketing through space at approximately 1.5 million miles
per hour, the collection of hydrogen and helium ions disrupted Earth's satellites,
ignited northern lights, and triggered voltage fluctuations in the trans-Atlantic
communication cables.
"It was a moderate storm," says NSF-funded physicist Lt. Col. Delores Knipp
of the U.S. Air Force Academy. It was also a glimpse of the future.
Knipp and colleagues organized an international team of 100 scientists
to perform a "tag-team" study of the event--each researcher studying a different
part of the bubble's voyage to and its effects on Earth. "This was the first
international and multi-agency coordinated effort to understand and diagnose
a large event in space weather," Knipp says. The group presented their results
at the American Geophysical Union meeting last May.
"It is important to study and understand these events now," explains Sunanda
Basu, NSF's Program Director for Aeronomy, "so we will have the ability
to predict future storms."
And the storms will come.
Solar activity is expected to increase as the sun moves toward solar maximum
at the end of the decade. The maximum is part of the sun's normal 11-year
cycle.
When solar storms send bubbles of gas pelting into Earth, Earth experiences
magnetic storms--periods of wild fluctuation in magnetic fields and electrical
currents.
Modern humans are more vulnerable than ever before to these storms, says
Ernest Hildner, director of the Space Environment Center at the National
Oceanic and Atmospheric Administration.
Humans depend on satellite technology and large energy grids, both of which
may be disrupted by magnetic storms, he explains. "If we have such a storm
at a time when New York City, Washington, and Baltimore are pulling power
out of Canada, it's very conceivable that we could have a full blackout."
With these threats in mind, the team used satellite data to diagnose the
1993 storm. They found that space weather is more complex than originally
thought, says Knipp.
For example, much of the storm's energy came from transient or unpredictable
elements. Scientists had assumed that most of the storm would be part of
a predictable cycle.
The research also confirmed concerns about satellites. As the streams of
ions rocketed through space, they pushed against Earth's magnetosphere
(the area around the planet which is affected by Earth's magnetic field),
allowing normally protected satellites to be exposed to storm conditions.
The
project succeeded because of cooperation of other countries, says Knipp.
For example, because of the placement of their satellites, Japanese
scientists had very useful data. The study gave them the opportunity to
share their information.
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