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Magnetic storm
may disrupt pagers,
broadcasts

It's caused by the eruption
of a giant sunspot,
scientists say

By Helen Altonn
Star-Bulletin

A magnetic storm this weekend could disrupt radio transmissions and satellites and produce colorful northern lights visible over most of the mainland.

Islanders aren't likely to see the aurora, which is rarely visible this far south, said University of Hawaii astronomer Donald Mickey. A full moon also would make it difficult to see, he said.

As for whether television, pager and radio reception will be affected, he said: "We don't know how to forecast these effects in enough detail so far to be able to tell whether TVs will be affected."

He said National Oceanic and Atmospheric Administration forecasters in Colorado expect the storm "to be large, but probably not devastating."

NOAA scientists reported that the solar flare already has caused some radio blackouts.

The sun may be nearing the peak of its 11-year cycle, known as solar maximum, Mickey said. "You never know (if you reach the peak) until it starts going down again."

A giant sunspot eruption just after midnight Hawaii time yesterday triggered the magnetic storm. Billions of tons of plasma and charged particles were ejected into space, some at 3 million miles an hour, NOAA scientists said.

The mass ejection was expected to hit the Earth's magnetic field this afternoon and cause the geomagnetic storm.

Mickey said the eruption was the biggest this cycle but there haven't been many. "We've been sort of wondering, expecting more big flares, and that hasn't happened so far." Sometimes larger flares happen later in the cycle, he said.

The latest eruption occurred in a very complex magnetic region near the visible part of the sun, Mickey said.

"When a large flare like this is at the surface, sometimes -- and this is one of those cases -- an amount of corona gets ejected into interplanetary space, leaving sort of a hole in the corona and sending basically a cloud of plasma out away from the sun," he said.

Cameras on the NASA spacecraft SOHO, positioned to look continuously at the sun, showed the ejection "and within minutes, the cameras were hit by clouds of very fast protons that showed up as snow on the images," Mickey said.

A severe solar storm in 1989 knocked out power stations serving Canada and northeastern states, and an electrical transformer in New Jersey.

UH astronomers are collaborating with scientists around the country to study the solar maximum.

Mickey said they're setting up interdisciplinary studies "that will try to understand this all the way from the sun to Earth and how it affects things we do in our daily lives."