Scientists have finally created an elusive particle known as the Shankar
skyrmion, more than 40 years after it was first theorized. And, in the
process, they may have modelled the rare phenomenon of ‘ball lightning’
on a quantum scale. Artist's impression.
That could pave the way for stable fusion reactors.
Scientists have finally
created an elusive particle known as the Shankar skyrmion, more than 40
years after it was first theorized.
And, in the process, they may have modeled the rare phenomenon of ‘ball lightning’ on a quantum scale.
Not
only could the discovery help to explain the mysterious natural
occurrence, which can appear as a sphere of electricity in the midst of
storms, but the experts say it could pave the way for more stable plasma
in fusion reactors.
In the new research, led
by scientists at Amherst College and Aalto University, the team created a
three-dimensional skyrmion in an extremely cold quantum gas.
The
three-dimensional particle consists of knots made from the spin fields
of a Bose-Einstein condensate – or, atoms cooled to a point just above
absolute zero.
According to the researchers, this bizarre tangle may share some of the characteristics of ball lightning.
‘It
is remarkable that we could create the synthetic electromagnetic knot,
that is, quantum ball lightning, essentially with just two
counter-circulating electric currents,’ says Dr Mikko Möttönen, who led
the research at Aalto University.
‘Thus, it may be possible that a natural ball lightning could arise in a normal lightning strike.’
To create the skyrmion, the researchers polarized the spin of each atom upward along an applied natural magnetic field.
Then, the field is suddenly changed.
This causes the field to ‘vanish’ in the middle of the condensate, which acts as a single system.
The
spins of the atoms then start to rotate in a new direction. But, with
the magnetic field pointing in all directions near zero, the spins
create a knot of linked loops, each pointing to a fixed direction.
In the new
research, led by scientists at Amherst College and Aalto University, the
team created a three-dimensional skyrmion in an extremely cold quantum
gas
The three-dimensional particle
consists of knots made from the spin fields of a Bose-Einstein
condensate – or, atoms cooled to a point just above absolute zero
While it can be loosened or moved, it cannot be untied, according to the researchers.
‘The
quantum gas is cooled down to a very low temperature where it forms a
Bose-Einstein condensate: all atoms in the gas end up in the state of
minimum energy,’ said Professor David Hall, from Amherst College.
‘The state does not behave like an ordinary gas anymore but like a single giant atom.’
‘What
makes this a skyrmion rather than a quantum knot is that not only does
the spin twist but the quantum phase of the condensate winds
repeatedly,’ Hall says.
WHAT IS BALL LIGHTNING?
The eerie orb-like glow created by ball lightning (pictured) has finally been explained by scientists
Researchers
from Zhejiang University in Hangzhou, China, have proposed that the
bright glow of lightning balls is created when microwaves become trapped
inside a plasma bubble.
Ball
lightning has been reported to appear during thunderstorms as a glow
for centuries. It can range from the size of a golf ball to several
metres across.
The glow appears in the
air for between one second and tens of seconds. There are a number of
reports of such glows injuring or even killing people and setting
buildings alight.
In a letter to the
Daily Mail in 1936, for instance, a reader described how he saw a
'large, red hot ball come down from the sky'.
'It
struck our house, cut the telephone wires, burnt the window frame, and
then buried itself in a tub of water which was underneath,' the letter
reads.
'At the tip
of a lightning stroke reaching the ground, a relativistic electron bunch
can be produced, which in turn excites intense microwave radiation,'
the scientists said in a research paper published in
Scientific Reports .
'The
latter ionizes the local air and the radiation pressure evacuates the
resulting plasma, forming a spherical plasma bubble that stably traps
the radiation.'
Microwaves trapped
inside the continue to generate plasma for a moments to maintain the
bright flashes seen during ball lightning, they added.
The
fireball eventually fades away as the radiation held within the bubble
starts to dissipate - and when microwaves leak out, the lightning balls
can dramatically explode.
According to the researchers, the knotted structure created by the atoms’ spins creates a knotted artificial magnetic field.
And, this matches that of ball lightning.
‘More
research is needed to know whether or not it is also possible to create
ball lightning with a method of this kind,’ Möttönen said.
‘Further
studies could lead to finding a solution to keep plasma together
efficiently and enable more stable fusion reactors than we have now.’
Post a Comment Blogger Facebook Disqus
Click to see the code!
To insert emoticon you must added at least one space before the code.