Giant laser experiment to recreate conditions at Sun’s heart

March 31st, 2009 - 5:18 pm ICT by ANI  

London, March 31 (ANI): Scientists are all set to start the US National Ignition Facility (NIF), which is literally a huge laser experiment aimed at recreating conditions at the heart of our Sun.

According to a report by BBC News, the experiment is designed to demonstrate the feasibility of nuclear fusion, a process that could offer abundant clean energy.

The lab will kick-start the reaction by focusing 192 giant laser beams on a tiny pellet of hydrogen fuel.

To work, it must show that more energy can be extracted from the process than is required to initiate it.

The California-based NIF is the largest experimental science facility in the US and contains the world’s most powerful laser. It has taken 12 years to build.

“This is a major milestone,” said Dr Ed Moses, director of the facility.

“We are well on our way to achieving what we set out to do - controlled, sustained nuclear fusion and energy gain for the first time ever in a laboratory setting,” he added.

Experiments will begin in June 2009, with the first significant results expected between 2010 and 2012.

Fusion is looked on as the “holy grail” of energy sources because of its potential to supply almost limitless clean energy.

But the challenge of creating a practical fusion reactor has eluded scientists for decades. Now, however, they believe they are nearing their goal.

Fusion naturally occurs at the centre of stars where huge gravitational pressure allows the process to happen at temperatures of about 10 million Celsius.

At the much lower pressures on Earth, temperatures to produce fusion need to be much higher - above 100 million Celsius.

NIF will focus on a process known as inertially confined fusion, in which these extreme temperatures are achieved using ultra powerful lasers.

“When all NIF lasers are fired at full energy, they will deliver 1.8 megajoules of ultraviolet energy to the target,” explained Dr Moses.

When fired, the pulse will last just a few nanoseconds (billionths of a second) but it will impart an energy equivalent to 500 trillion Watts.

This intense energy will be focused on a ball-bearing-sized pellet of fuel, ablating the surface and compressing the remaining material inwards.

“This process will create temperatures of 100 million degrees and pressures billions of times greater than Earth’s atmospheric pressure, forcing the hydrogen nuclei to fuse and release many times more energy than the laser energy required to spark the reaction,” said Dr Moses.

If it works, NIF will release 10 to 100 times more energy than the amount pumped into the lasers to kick-start the reaction. (ANI)

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