Posted on 04/08/2008 7:06:29 PM PDT by blam
Laser creates brightest light on Earth
By Roger Highfield, Science Editor
Last Updated: 3:01pm BST 08/04/2008
The brightest light on Earth now shines in a laboratory in Texas, one which will enable scientists to create a tabletop star.
The $14m Texas Petawatt laser reached greater than one petawatt - one thousand million million watts - of laser power in the past few days, making it the highest powered laser in the world, says Prof Todd Ditmire, a physicist at The University of Texas at Austin.
The laser in action in the lab, the blue glass amplifiers can also be seen
Prof Ditmire says that when the laser is turned on, it has the power output of more than 2,000 times the output of all power plants in the United States.
The laser is brighter than sunlight on the surface of the sun, but it only lasts for an instant, a 10th of a trillionth of a second (0.0000000000001 second). This is the key to the laser's power - it delivers modest energy in a microscopic unit of time.
Prof Ditmire and his colleagues at the Texas Centre for High-Intensity Laser Science will use the laser to create and study matter at some of the most extreme conditions in the universe, including temperatures greater than those in the sun - when gases break down into a soup of particles called a plasma - and solids at pressures of many billions of atmospheres.
This will allow them to explore many astronomical phenomena in miniature, such as mini-supernovas, tabletop stars and very high-density plasmas that mimic stellar objects.
"We use the laser to heat matter to a condition that is similar to the material one might find in an exotic object like a brown dwarf," says Prof Ditmire. " We create a state which is now often called "warm-dense matter". Such states exist in stellar interiors but we don't understand much about such matter's properties.
"Warm dense matter is interesting, and enigmatic because it is intermediate between the condensed matter state (ie normal solids) and hot plasmas, both states we understand well but both very different from each other. With a petawatt laser we can create such matter in the lab."
"We can learn about these large astronomical objects from tiny reactions in the lab because of the similarity of the mathematical equations that describe the events," says Prof Ditmire, director.
Such a powerful laser will also allow them to study advanced ideas for creating energy by controlled fusion, the same process that powers the Sun. A nozzle will spray clusters of deuterium (heavy hydrogen) atoms into the target chamber of the laser, where the beam will fuse them together, creating fusion power.
This is an alternative to another fusion power method, by confinement in magnetic fields, that will be studied by the vast international Iter fusion project. And the use of lasers this way is a traditional method used to study what happens inside H bomb warheads, as is done by Britain's Helen laser, which is why the facility is funded by the US Energy Department's National Nuclear Security Administration.
Prof Ditmire adds that there is a rival operating petawatt laser in the UK, the Vulcan laser at the Rutherford Appleton Laboratory, Oxfordshire. "The Texas Petawatt now (slightly) exceeds the power of Vulcan," he says, but adds "there has been some very nice science done recently on Vulcan."
To fire up the Texas laser, electrical charge has to be pumped into twenty 20,000-volt capacitors. These capacitors energise the amplification tubes that pump up the energy of the laser light beam. Each tube contains an amplifying material, usually glass, that is "excited" by lamps powered by the capacitors. Every time the laser passes through one of these sheets of glass it gains more energy.
The laser can only be fired in a "clean room," Prof Ditmire says, as it will produce so much power that it could blow apart any dust, hair or clothing fibres that enter the beam.
“The stars at night, are big and bright,
(clap, clap, clap),
deep in the heart of Texas!”
Do tell, do tell.
petawatts?? What was I thinking???
“The $14m Texas Petawatt laser reached greater than one petawatt - one thousand million million watts “
“Warning: Avoid staring directly into the beam”
Can I get those guys to shoot it at my next door neighbor, man he really bothers me.
Wrong warning.
The correct warning is “No not look into laser with remaining eye”
A friend of mine that used to work at a high powered laser lab, told me that when lasers get into the very high power range, there is a limit to how long it can fire because even at 99% reflectivity, The materials used as mirrors will melt with the tiny amount absorbed. Spooky but cool.
Great, let’s mount it in a Boeing and call it good
Yes, but I have dibs on it tomorrow, to mess wit’ the neighbors cat. Don’t know what it is but he never seems to get tired chasing that dot!
a cool new weapon.
Ten petawatt-femotoseconds would be ten joules. While that would be powerful enough to blind someone, the hazard level is nowhere near what the "petawatt" number would suggest. For most purposes a laser that output 10,000 watts for a millisecond would have about the same effect.
Yes...I don’t like to talk about it.
I don't mean to pry, but it might be good to get this all out. Only suggstin'.
Sometimes, discussing ones past can be good for the soul. Sort of cathartic.
In youth, when playing Army, I once claimed that I wasn't "shot" when I really was.
As a young soldier, my squad was once a attacked by an officer with a “god gun”- think a laser tag gun, than does rapid fire in all directions.
My 203 gunner, all without orders, dropped a smoke round in his jeep, convincing the officer to go elsewhere.
(It was a darn good shot, actually - a couple of hundred meters uphill, and the 203 round landed right in the passenger side of the jeep.)
Another point of light in a dark world.
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