How Far Away is Fusion? Unlocking the Power of the Sun
Δημοσιεύτηκε στις 27 Μαΐ 2017
The
Sun uses its enormous mass to crush hydrogen into fusion, releasing
enormous energy. How long will it be until we’ve got this energy source
for Earth?
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Team: Fraser Cain - @fcain / frasercain@gmail.com
Karla Thompson - @karlaii
Chad Weber - weber.chad@gmail.com
I’d like to think we’re smarter than the Sun.
Let’s
compare and contrast. Humans, on the one hand, have made enormous
advances in science and technology, built cities, cars, computers, and
phones. We have split the atom for war and for energy.
What has
the Sun done? It’s a massive ball of plasma, made up of mostly hydrogen
and helium. It just, kind of, sits there. Every now and then it burps
up hydrogen gas into a coronal mass ejection. It’s not a stretch to say
that the Sun, and all inanimate material in the Universe, isn’t the
sharpest knife in the drawer.
And yet, the Sun has mastered a
form of energy that we just can’t seem to wrap our minds around: fusion.
It’s really infuriating, seeing the Sun, just sitting there,
effortlessly doing something our finest minds have struggled with for
half a century.
Why can’t we make fusion work? How long until we can finally catch up technologically with a sphere of ionized gas?
The
trick to the Sun’s ability to generate power through nuclear fusion, of
course, comes from its enormous mass. The Sun contains 1.989 x 10^30
kilograms of mostly hydrogen and helium, and this mass pushes inward,
creating a core heated to 15 million degrees C, with 150 times the
density of water.
It’s at this core that the Sun does its work,
mashing atoms of hydrogen into helium. This process of fusion is an
exothermic reaction, which means that every time a new atom of helium is
created, photons in the form of gamma radiation are also released.
The
only thing the Sun uses this energy for is light pressure, to
counteract the gravity pulling everything inward. Its photons slowly
make their way up through the Sun and then they’re released into space.
So wasteful.
How can we replicate this on Earth?
Now
gathering together a Sun’s mass of hydrogen here on Earth is one option,
but it’s really impractical. Where would we put all that hydrogen. The
better solution will be to use our technology to simulate the conditions
at the core of the Sun.
If we can make a fusion reactor where
the temperatures and pressures are high enough for atoms of hydrogen to
merge into helium, we can harness those sweet sweet photons of gamma
radiation.
The main technology developed to do this is called a
tokamak reactor; it’s a based on a Russian acronym for: “toroidal
chamber with magnetic coils”, and the first prototypes were created in
the 1960s. There are many different reactors in development, but the
method is essentially the same.
A vacuum chamber is filled with
hydrogen fuel. Then an enormous amount of electricity is run through the
chamber, heating up the hydrogen into a plasma state. They might also
use lasers and other methods to get the plasma up to 150 to 300 million
degrees Celsius (10 to 20 times hotter than the Sun’s core).
Superconducting
magnets surround the fusion chamber, containing the plasma and keeping
it away from the chamber walls, which would melt otherwise.
Once
the temperatures and pressures are high enough, atoms of hydrogen are
crushed together into helium just like in the Sun. This releases photons
which heat up the plasma, keeping the reaction going without any
addition energy input.
Excess heat reaches the chamber walls, and can be extracted to do work.
The
challenge has always been that heating up the chamber and constraining
the plasma uses up more energy than gets produced in the reactor. We can
make fusion work, we just haven’t been able to extract surplus energy
from the system… yet.
Compared to other forms of energy
production, fusion should be clean and safe. The fuel source is water,
and the byproduct is helium (which the world is actually starting to run
out of). If there’s a problem with the reactor, it would cool down and
the fusion reaction would stop.
The high energy photons released
in the fusion reaction will be a problem, however. They’ll stream into
the surrounding fusion reactor and make the whole thing radioactive. The
fusion chamber will be deadly for about 50 years, but its rapid
half-life will make it as radioactive as coal ash after 500 years. Do
you know coal ash is radioactive?
Sun uses its enormous mass to crush hydrogen into fusion, releasing
enormous energy. How long will it be until we’ve got this energy source
for Earth?
Support us at: http://www.patreon.com/universetoday
More stories at: http://www.universetoday.com/
Follow us on Twitter: @universetoday
Like us on Facebook: https://www.facebook.com/universetoday
Google+ - https://plus.google.com/+universetoday/
Instagram - http://instagram.com/universetoday
Team: Fraser Cain - @fcain / frasercain@gmail.com
Karla Thompson - @karlaii
Chad Weber - weber.chad@gmail.com
I’d like to think we’re smarter than the Sun.
Let’s
compare and contrast. Humans, on the one hand, have made enormous
advances in science and technology, built cities, cars, computers, and
phones. We have split the atom for war and for energy.
What has
the Sun done? It’s a massive ball of plasma, made up of mostly hydrogen
and helium. It just, kind of, sits there. Every now and then it burps
up hydrogen gas into a coronal mass ejection. It’s not a stretch to say
that the Sun, and all inanimate material in the Universe, isn’t the
sharpest knife in the drawer.
And yet, the Sun has mastered a
form of energy that we just can’t seem to wrap our minds around: fusion.
It’s really infuriating, seeing the Sun, just sitting there,
effortlessly doing something our finest minds have struggled with for
half a century.
Why can’t we make fusion work? How long until we can finally catch up technologically with a sphere of ionized gas?
The
trick to the Sun’s ability to generate power through nuclear fusion, of
course, comes from its enormous mass. The Sun contains 1.989 x 10^30
kilograms of mostly hydrogen and helium, and this mass pushes inward,
creating a core heated to 15 million degrees C, with 150 times the
density of water.
It’s at this core that the Sun does its work,
mashing atoms of hydrogen into helium. This process of fusion is an
exothermic reaction, which means that every time a new atom of helium is
created, photons in the form of gamma radiation are also released.
The
only thing the Sun uses this energy for is light pressure, to
counteract the gravity pulling everything inward. Its photons slowly
make their way up through the Sun and then they’re released into space.
So wasteful.
How can we replicate this on Earth?
Now
gathering together a Sun’s mass of hydrogen here on Earth is one option,
but it’s really impractical. Where would we put all that hydrogen. The
better solution will be to use our technology to simulate the conditions
at the core of the Sun.
If we can make a fusion reactor where
the temperatures and pressures are high enough for atoms of hydrogen to
merge into helium, we can harness those sweet sweet photons of gamma
radiation.
The main technology developed to do this is called a
tokamak reactor; it’s a based on a Russian acronym for: “toroidal
chamber with magnetic coils”, and the first prototypes were created in
the 1960s. There are many different reactors in development, but the
method is essentially the same.
A vacuum chamber is filled with
hydrogen fuel. Then an enormous amount of electricity is run through the
chamber, heating up the hydrogen into a plasma state. They might also
use lasers and other methods to get the plasma up to 150 to 300 million
degrees Celsius (10 to 20 times hotter than the Sun’s core).
Superconducting
magnets surround the fusion chamber, containing the plasma and keeping
it away from the chamber walls, which would melt otherwise.
Once
the temperatures and pressures are high enough, atoms of hydrogen are
crushed together into helium just like in the Sun. This releases photons
which heat up the plasma, keeping the reaction going without any
addition energy input.
Excess heat reaches the chamber walls, and can be extracted to do work.
The
challenge has always been that heating up the chamber and constraining
the plasma uses up more energy than gets produced in the reactor. We can
make fusion work, we just haven’t been able to extract surplus energy
from the system… yet.
Compared to other forms of energy
production, fusion should be clean and safe. The fuel source is water,
and the byproduct is helium (which the world is actually starting to run
out of). If there’s a problem with the reactor, it would cool down and
the fusion reaction would stop.
The high energy photons released
in the fusion reaction will be a problem, however. They’ll stream into
the surrounding fusion reactor and make the whole thing radioactive. The
fusion chamber will be deadly for about 50 years, but its rapid
half-life will make it as radioactive as coal ash after 500 years. Do
you know coal ash is radioactive?
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