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RELEASE - 11-291
September 07, 2011
from
NASA Website
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NASA Has New Information
About Solar Flares:
Increased Strength and
Longevity |
WASHINGTON
NASA's Solar Dynamics Observatory,
or
SDO, has provided scientists new information about solar flares
indicating an increase in strength and longevity that is more than
previously thought.
Solar flares are intense bursts of radiation from the release of
magnetic energy associated with sunspots. They are the solar
system's largest explosive events and are seen as bright areas on
the sun. Their energy can reach Earth's atmosphere and affect
operations of Earth-orbiting communication and navigation
satellites.
Using SDO's Extreme ultraviolet Variability Experiment (EVE)
instrument, scientists have observed that radiation from solar
flares continue for up to five hours beyond the main phase.
The new data also show the total energy
from this extended phase of the solar flare's peak sometimes has
more energy than the initial event.
"Previous observations considered a
few seconds or minutes to be the normal part of the flare
process," said Lika Guhathakurta, lead program scientist for
NASA's Living with a Star Program at the agency's Headquarters
in Washington.
"This new data will increase our
understanding of flare physics and the consequences in
near-Earth space where many scientific and commercial satellites
reside."
On Nov. 3, 2010, SDO observed a solar
flare. If scientists only had measured the effects of the flare as
it initially happened, they would have underestimated the amount of
energy shooting into Earth's atmosphere by 70 percent.
SDO's new observations provide a much
more accurate estimation of the total energy solar flares put into
Earth's environment.
"For decades, our standard for
flares has been to watch the X-rays as they happen and see when
they peak," said Tom Woods, a space scientist at the University
of Colorado in Boulder and principal author on a paper in
Wednesday's online edition of Astrophysical Journal.
"But we were seeing peaks that
didn't correspond to the X-rays."
During the course of a year, the team
used EVE to map each wavelength of light as it strengthened, peaked,
and diminished over time. EVE records data every 10 seconds and has
observed many flares.
Previous instruments only measured every
90 minutes or didn't look at all wavelengths simultaneously as SDO
can.
To compliment the EVE graphical data, scientists used images from
another SDO instrument, the Advanced Imaging Assembly (AIA).
Analysis of these images showed the main flare eruption and its
extended phase in the form of magnetic field lines called coronal
loops that appeared far above the original eruption site.
These
extra loops were longer and became brighter later than the loops
from the main flare and also were physically set apart from those of
the main flare.
Because this previously unrealized extra source of energy from
flares also is impacting Earth's atmosphere, Woods and his
colleagues are studying how the late phase flares can influence
space weather. Space weather caused by solar flares can affect
communication and navigation systems, satellite drag and the decay
of orbital debris.
SDO was launched on Feb. 11, 2010. The spacecraft is the most
advanced spacecraft ever designed to study the sun and its dynamic
behavior. SDO provides images 10 times clearer than high definition
television and more comprehensive science data faster than any solar
observing spacecraft in history.
EVE was built by the Laboratory for Atmospheric and Space Physics at
the University of Colorado. AIA was built by Lockheed Martin Solar
and Astrophysics Laboratory in Palo Alto, Calif.
NASA's Goddard Space Flight Center in Greenbelt, Md., built,
operates and manages the SDO spacecraft for NASA's Science Mission
Directorate in Washington. SDO is the first mission of NASA's Living
with a Star Program, or LWS.
The goal of LWS is to develop the
scientific understanding necessary to address those aspects of the
connected sun-Earth system that directly affect our lives and
society.
More Information
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