NEW YORK (Reuters) - Three large explosions from the Sun over the past few days have prompted U.S. government scientists to caution users of satellite, telecommunications and electric equipment to prepare for possible disruptions over the next few days.

"The magnetic storm that is soon to develop probably will be in the moderate to strong level," said Joseph Kunches, a space weather scientist at the Space Weather Prediction Center, a division of the U.S. National Oceanic and Atmospheric Administration (NOAA).

He said solar storms this week could affect communications and global positioning system (GPS) satellites and might even produce an aurora visible as far south as Minnesota and Wisconsin.

An aurora, called aurora borealis or the northern lights in northern latitudes, is a natural light display in the sky in the Arctic and Antarctic regions caused by the collision of energetic charged particles with atoms in the high altitude atmosphere.

Major disruptions from solar activity are rare but have had serious impacts in the past.

In 1989, a solar storm took down the power grid in Quebec, Canada, leaving about six million people without power for several hours.

The largest solar storm ever recorded was in 1859 when communications infrastructure was limited to telegraphs.

The 1859 solar storm hit telegraph offices around the world and caused a giant aurora visible as far south as the Caribbean Islands.

Some telegraph operators reported electric shocks. Papers caught fire. And many telegraph systems continued to send and receive signals even after operators disconnected batteries, NOAA said on its website.

A storm of similar magnitude today could cause up to $2 trillion in damage globally, according to a 2008 report by the National Research Council.

"I don't think this week's solar storms will be anywhere near that. This will be a two or three out of five on the NOAA Space Weather Scale," said Kunches.

SOLAR SCALE

The NOAA Space Weather Scale measures the intensity of a solar storm from one being the lowest intensity to five being the highest, similar to scales that measure the severity of hurricanes, tornadoes and earthquakes.

The first of the three solar explosions from the sun this week already passed the Earth on Thursday with little impact, Kunches said, noting, the second was passing the Earth now and "seems to be stronger."

And the third, he said, "We'll have to see what happens over the next few days. It could exacerbate the disturbance in the Earth's magnetic field caused by the second (storm) or do nothing at all."

Power grid managers receive alerts from the Space Weather Prediction Center to tell them to prepare for solar events, which peak about every 12 years, Tom Bogdan, director of the center said.

He said the next peak, called a solar maximum, was expected in 2013.

"We're coming up to the next solar maximum, so we expect to see more of these storms coming from the sun over the next three to five years," Bogdan said.