The Raelian Movement
for those who are not afraid of the future : http://www.rael.org
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Researchers make magnetic fields breakthrough
http://www.physorg.com/news201526370.html
August 20, 2010
(PhysOrg.com) -- Researchers at the University of Dundee have made a
breakthrough in the study of magnetic fields, which enhances our
understanding of how stars, including the Sun, work.
The team from the Magnetohydrodynamics research group in the School of
Engineering, Physics and Mathematics used state-of-the-art computer
simulations of evolving plasmas in the Sun's atmosphere.
By following how the magnetic field and the plasma interact, they have
uncovered new rules that govern what evolutions are possible. Knowing
the basic rules behind the apparently complex solar atmosphere gives
the team hope of predicting how it will behave.
Magnetic fields cannot be directly seen, felt or tasted, but they are
a ubiquitous force of nature. The neat pattern of magnetic "field
lines" from a bar magnet is well-known from school physics
experiments. Indeed, the magnetic field of the Earth itself has a
similar pattern on a much larger scale, which is what enables
navigation by compass.
But magnetic fields are not always so ordered. Telescopic pictures of
the Sun's lower atmosphere taken in extreme-ultraviolet light, outside
the visible spectrum, reveal the shape of the magnetic field lines
because the plasma particles emitting the light are guided by magnetic
forces and move along the magnetic field lines.
These images often reveal braiding and tangling of the field, in a
manner that would render a compass useless. The fact that the magnetic
field lines are tangled like spaghetti means that the plasma in the
Sun's atmosphere is not free to move around however it pleases and
that vast quantities of energy can be locked in the magnetic field,
because tangled fields have more energy than ordered fields.
Scientists believe that this energy is responsible for heating the
Sun's atmosphere to million-degree temperatures, but how this works in
detail is a longstanding puzzle in solar physics. The Dundee team hope
their discovery will give us a better idea of just how this energy is
released.
'Using these computer simulations, we have studied braided magnetic
fields and made a significant advance in understanding how they evolve
over time,' said Dr Gunnar Hornig, one of the paper's authors.
'You can observe magnetic fields on the Sun with satellites and see
that these structures are often braided. That is they are not just
simple loops, but these loops interlink.
'These structures are not static. They evolve because the Sun is not a
rigid body but essentially a plasma ball of gas. It kind of boils, and
the motion on the surface changes these magnetic structures. They
start to move them around and sometimes the braiding is increased. And
if certain critical conditions are met then these structures start to
relax to something simpler.
'If you take a twig of a branch and start to twist it, then at some
point it starts to break and the individual fibres break up. Something
similar happens to these magnetic fields. Where it differs is that the
evolutions we have been studying allow the broken fields to combine to
form new structures.'
Having investigated how magnetic field braiding works in a specific
instance, the team will now switch their attention to examining how
they work in more general, complex structures.
'We began by looking at braided magnetic fields in the Sun's
atmosphere,' explained Dr Anthony Yeates, one of the team members. 'We
know that these magnetic fields break up and reconnect and we have now
discovered new rules governing which evolutions are possible and how
this is happening.
'This is fundamental research - part of the theory of astrophysical
plasmas. It forms part of our attempts to understand how stars work,
which enhances our understanding of how our own Sun evolves, and how
it affects the climate and life on Earth.'
Their research has been published in the latest edition of Physical
Review Letters, as a paper entitled 'Topological constraints on
magnetic relaxation'.
The ongoing research project on quantifying magnetic fluxes started
last October, and is funded by the Science and Technology Facilities
Council.
Provided by University of Dundee
------------------------------------
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Ethics" is simply a last-gasp attempt by deist conservatives and
orthodox dogmatics to keep humanity in ignorance and obscurantism,
through the well tried fermentation of fear, the fear of science and
new technologies.
There is nothing glorious about what our ancestors call history,
it is simply a succession of mistakes, intolerances and violations.
On the contrary, let us embrace Science and the new technologies
unfettered, for it is these which will liberate mankind from the
myth of god, and free us from our age old fears, from disease,
death and the sweat of labour.
Rael
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-----------------------------------------------------------------
Tell your friends who love scientific news that they can
subscribe to this list !!
They can do it by sending a blank email to:
rael-science-select-subscribe@yahoogroups.com
It's free !
-----------------------------------------------------------------
To unsubscribe, send an email to:
rael-science-select-unsubscribe@yahoogroups.com
-----------------------------------------------------------------
To change your e-mail address, unsubscribe from the old address and subscribe from the new address (see above).
-----------------------------------------------------------------
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/rael-science-select/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/rael-science-select/join
(Yahoo! ID required)
<*> To change settings via email:
rael-science-select-digest@yahoogroups.com
rael-science-select-fullfeatured@yahoogroups.com
<*> To unsubscribe from this group, send an email to:
rael-science-select-unsubscribe@yahoogroups.com
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
0 comments:
Post a Comment