PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
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Contact: Diane Ainsworth
FOR IMMEDIATE RELEASEFebruary 19, 1996
SOLAR STORMS LINKED TO MAGNETIC DISTURBANCES ON EARTH
Scientists observing solar storms with a soft x-ray
telescope on board the orbiting Japanese Yohkoh satellite have
found a direct link between the solar eruptions and magnetic
storms in Earth's upper atmosphere.
"This is the first time that we have been able to see these
high temperature regions at the center of the Sun in x-ray
images," said Dr. Hugh Hudson, an astronomer at the University of
Hawaii, during an international conference on magnetic storms
held Feb. 12-16 at NASA's Jet Propulsion Laboratory.
"The Sun's outer atmosphere, the corona, dims just before
these particles are ejected, allowing us to watch the bright flow
of material as it is flung into space," Hudson told physicists,
power and utility company representatives and members of the
Department of Energy's national laboratories. "It's this dimming
signature in the Sun's corona that tells us a magnetic storm is
on the way."
All of the causes of magnetic storms originate at the Sun,
researchers reported at the weeklong conference, co-sponsored by
the American Geophysical Union and the National Science
Foundation. The particle storms begin when large amounts of
coronal mass break away from the Sun and travel rapidly toward
"Magnetic storms are caused by abrupt, intense events on the
Sun, which impact Earth's magnetic field," said Dr. Bruce
Tsurutani, a plasma physicist at JPL and co-convener of the
conference. "If we can predict that these storms will occur,
certainly we will be able to reduce the cost of damage on Earth."
New observations at latitudes above and below the Sun's
equator point to that possibility. Scientists observing these
events as they occur can give industries hardest hit, such as the
power and electric utilities, 50 to 70 hours of advance warning
that a magnetic disturbance is imminent.
"These releases of great amounts of the outer corona travel
very rapidly toward Earth, at thousands of kilometers per second
and, in some cases, tens of thousands of kilometers per second,"
explained Dr. Douglas Hamilton, a professor of physics at the
University of Maryland. "Magnetic clouds take two to three days
to arrive at Earth."
Major disturbances from the Sun erupt about every three to
four years, resulting in widespread power blackouts. The most
severe in recent years struck in 1989, when an outage in the
Quebec province almost shut down the entire northeastern U.S.
grid as well, said John Kappenman, an engineer at Minnesota
Sometimes the collisions produce auroras, shimmering
curtains of light in the northern and southern hemispheres. Other
times they create large fluctuating currents that wreck havoc
with technologies on the ground. Kappenman said that with a few
days advance notice, power and utility companies could mitigate
damage by shutting down transformers or redirecting power through
Once the storms enter Earth's ionosphere, they alter the
composition of the Van Allen radiation belts, Hamilton said.
During intense solar storms, large amounts of electrically
charged oxygen are drawn out of Earth's upper atmosphere and
become part of the radiation belts.
"We once thought that the Van Allen radiation belts were
made up of electrons and protons, the simplest subatomic charged
particles, but we know now that in these very large storms, a
vast amount of electrically charged oxygen is drawn into them and
can intensify the belts by a factor of 10 to 20," Hamilton said.
"We're learning that the Earth is not just a passive
bystander getting buffeted by clouds of solar gas," he said.
"Rather, the Earth itself, the very tenuous upper reaches of the
atmosphere, contain a lot of electrically charged matter that
contributes new particles to the Van Allen belt."
North America is, by far, the most vulnerable to magnetic
fluctuations, Kappenman added. The landmass is closest to Earth's
magnetic north pole and outranks other industrial centers as
having the largest and most complex power grids.
A recent power industry study, spanning 25 years of magnetic
storms, revealed correlations between disturbances in the upper
atmosphere and blackouts at power plants from Maine to
California, he said.
"Rock geologies in North America are extremely vulnerable to
these magnetic storms because they complicate or add coupling
effects to power systems," Kappenman said. "The failures are
occurring in fairly large numbers and we see patterns in failure
rates in different parts of the country."
New England, for example, has a transformer failure rate
that is 60 percent higher than other regions of the country due
to its geological composition. The Pacific Northwest, similarly,
revealed a transformer failure rate 48 percent higher than other
regions of the U.S.
"These power outages are one of the biggest nightmares we
live with in the power industry," Kappenman said, "in that the
duration of an outage could be several hours, possibly extending
into days. The cost to industry well exceeds $100 million in
failed equipment alone. These storms not only hamper critical
public services but cause life threatening situations."
NASA is participating in the international Solar-Terrestrial
Physics program to launch new spacecraft to study space weather
for the benefit of human life. With new spacecraft such as Polar
and the Advanced Composition Explorer, researchers believe storm
forecasting will reach new levels of accuracy and allow
industries enough time to safeguard communities all over the