The next maximum is predicted to be huge.
From the Yahoo Southern Aurora Group:
Issued at 0839 UTC March 09, 2006. (9:39 PM NZ daylight time, March
09)
Hello people.
While things are a bit quiet on the solar front, I thought I'd pass
this story along from NASA. A group of scientists claim that the
next solar cycle could the strongest for a century. If correct, that
could be good news for aurora watchers, but bad news for satelite
owners... Have they got it right? Only time will tell, but it would
be nice!
Enjoy the story.
Clear skies.
Graham Palmer
Hastings, New Zealand.
Home phone: 06-8781109
Graham's cell No: 021-2650487
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RELEASE: 06-087
NASA AIDS IN RESOLVING LONG STANDING SOLAR CYCLE MYSTERY
Scientists predict the next solar activity cycle will be 30 to 50
percent stronger than the previous one and up to a year late.
Accurately predicting the sun's cycles will help plan for the
effects
of solar storms. The storms can disrupt satellite orbits and
electronics; interfere with radio communication; damage power
systems; and can be hazardous to unprotected astronauts.
The breakthrough "solar climate" forecast by Mausumi Dikpati and
colleagues at the National Center for Atmospheric Research in
Boulder, Colo. was made with a combination of computer simulation
and
groundbreaking observations of the solar interior from space using
NASA's Solar and Heliospheric Observatory (SOHO). NASA's Living With
a Star program and the National Science Foundation funded the
research.
The sun goes through a roughly 11-year cycle of activity, from
stormy
to quiet and back again. Solar storms begin with tangled magnetic
fields generated by the sun's churning electrically charged gas
(plasma). Like a rubber band twisted too far, solar magnetic fields
can suddenly snap to a new shape, releasing tremendous energy as a
flare or a coronal mass ejection (CME). This violent solar activity
often occurs near sunspots, dark regions on the sun caused by
concentrated magnetic fields.
Understanding plasma flows in the sun's interior is essential to
predicting the solar activity cycle. Plasma currents within the sun
transport, concentrate, and help dissipate solar magnetic
fields. "We
understood these flows in a general way, but the details were
unclear, so we could not use them to make predictions before,"
Dikpati said. Her paper about this research was published in the
March 3 online edition of Geophysical Research Letters.
The new technique of "helioseismology" revealed these details by
allowing researchers to see inside the sun. Helioseismology traces
sound waves reverberating inside the sun to build up a picture of
the
interior, similar to the way an ultrasound scan is used to create a
picture of an unborn baby.
Two major plasma flows govern the cycle. The first acts like a
conveyor belt. Deep beneath the surface, plasma flows from the poles
to the equator. At the equator, the plasma rises and flows back to
the poles, where it sinks and repeats. The second flow acts like a
taffy pull. The surface layer of the sun rotates faster at the
equator than it does near the poles. Since the large-scale solar
magnetic field crosses the equator as it goes from pole to pole, it
gets wrapped around the equator, over and over again, by the faster
rotation there. This is what periodically concentrates the solar
magnetic field, leading to peaks in solar storm activity.
"Precise helioseismic observations of the 'conveyor belt' flow speed
by the Michelson Doppler Imager (MDI) instrument on board SOHO gave
us a breakthrough," Dikpati said. "We now know it takes two cycles
to
fill half the belt with magnetic field and another two cycles to
fill
the other half. Because of this, the next solar cycle depends on
characteristics from as far back as 40 years previously - the sun
has
a magnetic 'memory'."
The magnetic data input comes from the SOHO/MDI instrument and
historical records. Computer analysis of the past eight years'
magnetic data matched actual observations over the last 80 years.
The
team added magnetic data and ran the model ahead 10 years to get
their prediction for the next cycle. The sun is in the quiet period
for the current cycle (cycle 23).
The team predicts the next cycle will begin with an increase in
solar
activity in late 2007 or early 2008, and there will be 30 to 50
percent more sunspots, flares, and CMEs in cycle 24. This is about
one year later than the prediction using previous methods, which
rely
on such statistics as the strength of the large-scale solar magnetic
field and the number of sunspots to make estimates for the next
cycle. This work will be advanced by more detail observations from
the Solar Dynamics Observatory, scheduled to launch in August 2008.
SOHO is a project of international collaboration between NASA and
the
European Space Agency. For images explaining the data on the Web,
visit:
http://www.nasa.gov/vision/universe/..._graphics.html
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