Gizmodo
America Fires the Most Powerful Laser In History
By Jesus Diaz
Mar 21, 2012
The United States' National Ignition Facility at the Lawrence Livermore
National Lab in California has fired the most powerful laser in history, a
record-breaking 2-megajoule shot. The laser was originally designed to reach
1.875-megajoules, but beat everyone's expectations—and set a new world
record in the process.
192 laser beams combined to form the single shot, initially reaching 1.875
megajoules. By the time it passed through its final focusing lens, the
laser maxed out at 2.03 megajoules, making it the world's first 2-megajoule
ultraviolet laser. Better yet, the blast caused less damage to the laser
optics than predicted, which allowed the facility to fire another shot just 36
hours after the 2.03-megajoule one.
How it works
It all starts with a single laser, which is split into 48 separate beams.
The beams are then redirected, using mirrors, into amplifiers that have been
previously pumped by a total of 7,680 Xenon flash lamps. After four
bounces, the beams are further split into 192 rays through all the
facility—which
is the size of three football fields. As they travel through those endless
tubes, the beams are amplified again at an exponential rate.
The result: from a tiny 1/billionth of a joule laser, the scientists at the
National Ignition Facility obtain rays "a foot on their side" with a
combined "2.03 million joules of ultraviolet energy," 1,000 times the energy
of
all the power plants in the United States combined, even while it's only
for a fraction of a second.
This time, the facility wasn't firing into any target. This will come later
in the year, as the facility—which is supported by the US Nuclear Weapons
Complex—races to achieve ignition in its first nuclear fusion experiment.
What does that entail? The powerful lasers will compress this frozen
hydrogen fuel cell, which will itself be enclosed in a gold-plated cylinder
called the hohlraum. The hohlraum is located inside a 32.8-foot-diameter
ignition chamber, and it will transform the lasers into extremely intense
X-rays,
compressing the hydrogen at one hundred billion atmospheres in just
1/1,000,000 of a second.
This will trigger a controlled nuclear fusion reaction that will create a
small star, hopefully generating more power than the energy used to fire the
laser and contain the intense heat inside the chamber. If this is
successful, we may be witnessing the beginning of a new clean power source
that may
end our dependency on fission nuclear power, oil and coal.
According to Ed Moses—director of the National Ignition Faciliy—"it's a
remarkable demonstration of the laser from the standpoint of its energy, its
precision, its power, and its availability." .....
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