Skeleton on Sun's atmosphere reveals its true nature (Forwarded)

Royal Astronomical Society
London, U.K.

Issued by RAS Press Officers:

Robert Massey
Tel: +44 (0)20 7734 4582
AND
Anita Heward
Tel: +44 (0)1483 420 904

NATIONAL ASTRONOMY MEETING PRESS ROOM (16 - 20 APRIL ONLY):
Tel: +44 (0)1772 892 613
+44 (0)1772 892 475
+44 (0)1772 892 477

RAS Web site:
http://www.ras.org.uk/

RAS National Astronomy Meeting web site:
http://nam2007.uclan.ac.uk

CONTACTS:

Dr Clare Parnell
School of Mathematics and Statistics
University of St. Andrews
Tel: +44 (0)1334 463706

Dr Andrew Haynes
School of Mathematics and Statistics
University of St. Andrews
Tel: +44 (0)1334 463728

From 16 to 20 April, Dr Parnell and Andrew Haynes can be contacted via the
NAM press office (see above).

PRESS INFORMATION NOTE: RAS PN 07/09 (NAM 05)

EMBARGOED FOR 00:01 BST, 16 APRIL 2007

SKELETON OF SUN'S ATMOSPHERE REVEALS ITS TRUE NATURE

The Sun's outer atmosphere or corona is incredibly complex, as shown in
observations from space. It is also extremely hot, with a temperature of
over a million degrees by comparison with that of the Sun's surface of
only 6000 degrees. Scientists have now made a major breakthrough in
understanding this complexity by studying the 'skeleton' of the magnetic
field. A team of scientists from St Andrew's University will present the
results on Monday 16 April at the Royal Astronomical Society National
Astronomy Meeting in Preston. "It is the Sun's magnetic field that
dominates the behaviour of the corona and determines its structure", said
team member Andrew Haynes, "and our work is a key step forward in
understanding its structure".

Until now the complexity of the magnetic field has baffled solar
scientists. Professor Eric Priest first proposed the concept of the solar
skeleton in 1996. It consists of the key elements on which the complex
shape of the magnetic field is built. "We realised", added Dr Clare
Parnell, "that by constructing the skeleton of the field, we could unravel
this complexity and hopefully determine how the corona is heated".

Dr Parnell and colleagues have managed to develop a computer experiment,
which simulates the complex structure of the corona and have found that
the coronal heating is focused in specific parts of the skeleton. "In
future", she added, "we should be able to compare this type of analysis
with dramatic new observations from the recently launched Hinode
spacecraft and thereby really nail down the heating mechanism".

The work of the St Andrew's team indicates that the solar skeleton changes
continually and has a much richer structure than anyone imagined. Their
work is a building block in astronomers' efforts to better understand
events such as the solar flares and coronal mass ejections that eject
billions of tonnes of matter into space.

NOTES FOR EDITORS

The 2007 RAS National Astronomy Meeting is hosted by the University of
Central Lancashire. It is sponsored by the Royal Astronomical Society and
the UK Science and Technology Facilities Council.

This year the NAM is being held together with the UK Solar Physics (UKSP)
and Magnetosphere, Ionosphere and Solar-Terrestrial (MIST) spring
meetings. 2007 is International Heliophysical Year.

IMAGE CAPTIONS:

[Image 1:
http://www-solar.mcs.st-and.ac.uk/~clare/NAM07/parnell_haynes1.png
(133KB)]
The complex magnetic field in the solar atmosphere. The particular field
lines drawn are the ones likely to be heated and therefore observed on the
Sun.

[Image 2:
http://www-solar.mcs.st-and.ac.uk/~clare/NAM07/parnell_haynes2.gif
(233KB)]
Typical image of the solar corona clearly revealing the complex tangle of
heated magnetic loops from TRACE (Image: NASA).

[Image 3:
http://www-solar.mcs.st-and.ac.uk/~clare/NAM07/parnell_haynes3.png (21KB)]
Simulated image of the interaction of a pair of magnetic fragments with
opposite polarities. The yellow lines (regions) are the heating sites and
the red and blue field lines show the magnetic skeleton.


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