Monster Solar Flare Waves On The Sun Are Real

[Pastor Dale Morgan]

*Signs In The Sun, The Moon and The Stars

Monster Solar Flare Waves On The Sun Are Real*

A solar tsunami seen by the STEREO spacecraft from orthogonal points of
view. The gray part of the animation has been contrast-enhanced by
subtracting successive pairs of images, resulting in a "difference movie."

by Dr. Tony Phillips
Huntsville AL (SPX) Nov 25, 2009

Sometimes you really can believe your eyes. That's what NASA's STEREO
(Solar Terrestrial Relations Observatory) spacecraft are telling
researchers about a controversial phenomenon on the sun known as the
"solar tsunami."

Years ago, when solar physicists first witnessed a towering wave of hot
plasma racing along the sun's surface, they doubted their senses.

The scale of the thing was staggering. It rose up higher than Earth
itself and rippled out from a central point in a circular pattern
millions of kilometers in circumference. Skeptical observers suggested
it might be a shadow of some kind-a trick of the eye-but surely not a
real wave.

"Now we know," says Joe Gurman of the Solar Physics Lab at the Goddard
Space Flight Center. "Solar tsunamis are real."

The twin STEREO spacecraft confirmed their reality in February 2009 when
sunspot 11012 unexpectedly erupted. The blast hurled a billion-ton cloud
of gas (a "CME") into space and sent a tsunami racing along the sun's
surface. STEREO recorded the wave from two positions separated by 90o,
giving researchers an unprecedented view of the event

"It was definitely a wave," says Spiros Patsourakos of George Mason
University, lead author of a paper reporting the finding in the
Astrophysical Journal Letters. "Not a wave of water," he adds, "but a
giant wave of hot plasma and magnetism."

The technical name is "fast-mode magnetohydrodynamical wave"-or "MHD
wave" for short. The one STEREO saw reared up about 100,000 km high, and
raced outward at 250 km/s (560,000 mph) packing as much energy as 2400
megatons of TNT (1029 ergs).

Solar tsunamis were discovered back in 1997 by the Solar and
Heliospheric Observatory (SOHO). In May of that year, a CME came
blasting up from an active region on the sun's surface, and SOHO
recorded a tsunami rippling away from the blast site.

"We wondered," recalls Gurman, "is that a wave-or just a shadow of the
CME overhead?"

SOHO's single point of view was not enough to answer the
question-neither for that first wave nor for many similar events
recorded by SOHO in years that followed.

The question remained open until after the launch of STEREO in 2006. At
the time of the February 2009 eruption, STEREO-B was directly over the
blast site while STEREO-A was stationed at right angles -"perfect
geometry for cracking the mystery," says co-author Angelos Vourlidas of
the Naval Research Lab in Washington DC.

The physical reality of the waves has been further confirmed by movies
of the waves crashing into things. "We've seen the waves reflected by
coronal holes (magnetic holes in the sun's atmosphere)," says Vourlidas.
"And there is a wonderful movie of a solar prominence oscillating after
it gets hit by a wave. We call it the 'dancing prominence.'"

Solar tsunamis pose no direct threat to Earth. Nevertheless, they are
important to study. "We can use them to diagnose conditions on the sun,"
notes Gurman.

"By watching how the waves propagate and bounce off things, we can
gather information about the sun's lower atmosphere available in no
other way."

"Tsunami waves can also improve our forecasting of space weather," adds
Vourlidas, "Like a bull-eye, they 'mark the spot' where an eruption
takes place. Pinpointing the blast site can help us anticipate when a
CME or radiation storm will reach Earth."

And they're pretty entertaining, too. "The movies," he says, "are out of
this world."