Lockheed Martin researcher provides clues to space weather mystery

LOCKHEED MARTIN RESEARCHER PROVIDES CLUES TO SPACE WEATHER MYSTERY

PALO ALTO, CALIF., May 24, 2005

The most intense burst of solar radiation in five decades accompanied a
large solar flare on January 20. It shook space weather theory and
highlighted the need for new forecasting techniques, according to several
presentations at the American Geophysical Union (AGU) meeting this week in
New Orleans. Dr. Richard Nightingale of the Lockheed Martin (NYSE: LMT)
Solar and Astrophysics Laboratory (LMSAL) in Palo Alto, called upon his
research into rotating sunspots to provide a piece of the puzzle.

The solar flare, which occurred at 2 a.m. EST, tripped radiation monitors
all over the planet and scrambled detectors on spacecraft. The shower of
energetic protons came minutes after the first sign of the flare. This flare
was an extreme example of the type of radiation storm that arrives too
quickly to warn interplanetary astronauts.

"This flare produced the largest solar radiation signal on the ground in
nearly 50 years," said Dr. Richard Mewaldt of the California Institute of
Technology, Pasadena, Calif. He is a co-investigator on NASA's Advanced
Composition Explorer (ACE) spacecraft. "But we were really surprised when we
saw how fast the particles reached their peak intensity and arrived at
Earth."

Normally it takes two or more hours for a dangerous proton shower to reach
maximum intensity at Earth after a solar flare. The particles from the
January 20 flare peaked about 15 minutes after the first sign.

"That's important because it's too fast to respond with much warning to
astronauts or spacecraft that might be outside Earth's protective
magnetosphere," Mewaldt said. "In addition to monitoring the sun, we need to
develop the ability to predict flares in advance if we are going to send
humans to explore our solar system."

The event shakes the theory about the origin of proton storms at Earth.
"Since about 1990, we've believed proton storms at Earth are caused by shock
waves in the inner solar system as coronal mass ejections plow through
interplanetary space," said Professor Robert Lin of the University of
California at Berkeley. He is principal investigator for the Reuven Ramaty
High Energy Solar Spectroscopic Imager (RHESSI). "But the protons from this
event may have come from the sun itself, which is very confusing."

The origin of the protons is imprinted in their energy spectrum, as measured
by ACE and other spacecraft, which matches the energy spectrum of gamma-rays
thrown off by the flare, as measured by RHESSI. "This is surprising because
in the past we believed the protons making gamma-rays at the flare were
produced locally and the ones at the Earth were produced instead by shock
acceleration in interplanetary space," Lin said. "The similarity of the
spectra suggests they are the same."

Solar flares and coronal mass ejections (CMEs), associated giant clouds of
plasma in space, are the largest explosions in the solar system. They are
caused by the buildup and sudden release of magnetic stress in the solar
atmosphere above the giant magnetic poles we see as sunspots. The
Transitional Region and Coronal Explorer (TRACE) and the Solar and
Heliospheric Observatory (SOHO) spacecraft are devoted to observing the sun
and identifying the root causes of flares and CMEs, with an eye toward
forecasting them.

"We do not know how to predict the flow of energy into and through these
large flares," said Dr. Richard Nightingale of LMSAL, where the
high-resolution TRACE solar telescope was designed and built. "Instruments
like TRACE give us new clues with each event we observe."

TRACE has identified a possible source of the magnetic stress that causes
solar flares. The sunspots that give off the very largest (X-class) flares
appear to rotate in the days around the flare. "This rotation stretches and
twists the magnetic field lines over the sunspots," Nightingale said. "We
have seen it before virtually every X-flare that TRACE has observed since it
was launched and in more than half of all flares in that time."

However, rotating sunspots are not the whole story. The unique flare came at
the end of a string of five other very large flares from the same sunspot
group, and no one knows why this one produced more sudden high energy
particles than the first four.
"It means we really don't understand how the sun works," Lin said. "We need
to continue to operate and exploit our fleet of solar-observing spacecraft
to identify how it works."

Contact:
For more information and graphics about this story on the Web, visit:

http://www.nasa.gov/vision/universe/...fireworks.html

Media Contacts:
Buddy Nelson, Lockheed Martin, (510) 797-0349
Dolores Beasley, NASA Headquarters, (202) 358-1753
Rachel Weintraub, Goddard Space Flight Center, (301) 286-0918



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Jacques :-)

www.spacepatches.info