The Sun's magnetic fountains (Forwarded)

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NAM 2008
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CONTACTS:

Dr Michelle Murray
Mullard Space Science Laboratory
University College London
Tel: +44 (0)1483 204211

Deb Baker
Mullard Space Science Laboratory
University College London
Tel: +44 (0)1483 204179

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EMBARGOED UNTIL 0001 BST, 2 April 2008

Ref.: PN 08/26 (NAM 17)

The Sun's magnetic fountains

Astronomers have known for decades that the Sun has a very dynamic
atmosphere. Huge fountains of hot gas erupt in the atmosphere, or corona,
every few minutes, travelling at tens of thousands of km per hour and
reaching great heights. Now a team of scientists have used the Hinode
spacecraft to find the origin and driver of these fountains -- immense
magnetic structures that thread through the solar atmosphere. On Wednesday 2
April at the Royal Astronomical Society National Astronomy Meeting in
Belfast (NAM 2008), team leader Dr Michelle Murray from the Mullard Space
Science Laboratory (MSSL, University College London) will present the latest
results from Hinode together with computer simulations that model conditions
on the Sun.

Since its launch in October 2006, scientists have been using Hinode to
examine the solar atmosphere in extraordinary detail. One of the instruments
on the space observatory, the Extreme Ultraviolet Imaging Spectrometer (EIS)
built by a consortium led by MSSL, generates images of the Sun and gives
information on how fast its gases are moving.

Increases in pressure at the base of the Sun's magnetic field cause enormous
jets of hot gas to shoot upwards into the solar atmosphere. Once the
pressure ceases, the hot gases stop soaring into the atmosphere and fall
back towards the solar surface. The changes in pressure are caused by
rearrangements of the Sun's magnetic field, a continual process that results
in looping cycles of increasing and decreasing pressure and,
consequentially, intermittent solar fountains.

"EIS has observed the Sun's fountains in unprecedented detail and it has
enabled us to narrow down the fountains' origins for the first time,"
comments team member and MSSL postgraduate student Deb Baker.

"We have also been able to find what drives the fountains by using computer
experiments to replicate solar conditions."

"The computer experiments demonstrate that when a new section of magnetic
field pushes through the solar surface it generates a continual cycle of
fountains," explains Dr Murray, "but new magnetic fields are constantly
emerging across the whole of the solar surface and so our results can
explain a whole multitude of fountains that have been observed with Hinode."

IMAGES AND MOVIES

Images and movies of the fountains:
http://www.mssl.ucl.ac.uk/~mjm/NAM08/

Image and movie captions

Figure 1:
During a total solar eclipse the Moon passes in front of the Sun, blocking
out the most intense solar light and allowing us to view the Sun's
atmosphere, or corona, from Earth. The Sun's light can be seen streaming
through the immense magnetic structures that thread through the corona and
stretch out into space. Image credit: Luc Viatour GFDL/CC

Movie 1:
At the northern pole of the Sun, an incredibly fast fountain of hot gases
shoots above the edge of the solar disk into the atmosphere before falling
back down to the surface. In the foreground, gases bubble away at
temperatures approaching millions of degrees Celsius. This movie was
assembled from images captured with the EIS instrument, aboard the Hinode
spacecraft, on 1 April 2007. Movie: Jian Sun / MSSL / UCL / JAXA / NAOJ /
NASA / ESA / NSC

FURTHER INFORMATION

* Mullard Space Science Laboratory
http://www.mssl.ucl.ac.uk
* ESA
http://www.esa.int
* JAXA
http://www.jaxa.jp
* NASA
http://www.nasa.gov
* NSC
http://www.spacecentre.no

NOTES FOR EDITORS

The Hinode (Japanese for sunrise) mission was launched in October 2006. It
is used to study magnetic fields on the Sun and their role in powering the
solar atmosphere and driving solar eruptions. Hinode was developed and
launched by the Japanese Space Agency ISAS/JAXA, with the National
Astronomical Observatory of Japan (NAOJ) as the domestic partner and NASA
and the UK Science and Technology Facilities Council (STFC) as international
partners. It is operated by these agencies in co-operation with the European
Space Agency (ESA) and the Norwegian Space Centre (NSC). The Extreme
Ultraviolet Imaging Spectrometer (EIS) was built by a consortium led by
MSSL.

The RAS National Astronomy Meeting (NAM 2008) is hosted by Queen's
University Belfast. It is principally sponsored by the RAS and the Science
and Technology Facilities Council (STFC). NAM 2008 is being held together
with the UK Solar Physics (UKSP) and Magnetosphere, Ionosphere and
Solar-Terrestrial (MIST) spring meetings.