Laser-Powered Accelerators the Cutting Edge in Particle Physics

Scientists behind a new theoretical study suggest that laser-plasma particle accelerators, which offer a cheaper and smaller version of traditional particle accelerators, might be easier to construct than previously thought.

Such accelerators use lasers to energize electrons over very short distances - say, the length of a football field - rather than needing the miles-long tunnels of particle accelerators like the Large Hadron Collider (LHC) that uses traditional high-power radio frequency (RF) waves to accomplish the same task.

Not to mention that laser-plasma accelerators could outperform the traditional RF waves for far less than the $9 billion cost of the LHC, the researchers said.

In this cutting edge system, a powerful laser beam is blasted into a cloud of unattached, floating electrons and ions - a plasma cloud.

"The effect is like the wake of boat speeding down a lake. If the wake was big enough, a surfer could ride it," Wim Leemans, a physicist at Lawrence Berkeley National Laboratory's Berkeley Lab Laser Accelerator (BELLA) Center, said in a statement.

"Imagine that the plasma is the lake and the laser is the motorboat. When the laser plows through the plasma, the pressure created by its photons pushes the electrons out of the way. They wind up surfing the wake, or wakefield, created by the laser as it moves down the accelerator," he explained.

As the fast moving electrons leave the heavy ions behind, their separation would create gigantic electric fields 100 to 1,000 times larger than those in conventional accelerators, researchers said.

Although in theory the technology seems like a no brainer, some challenges do have to be overcome, researchers admitted.

Such an accelerator would need a laser in the petawatt power range capable of delivering thousands of pulses per second - BELLA currently has the highest repetition of any such device in the world, but it's just one pulse per second.

Some suggest using an array of smaller lasers to produce one enormous pulse, but synchronizing them all precisely together presents some technical difficulty.

If laser-plasma accelerators could be developed, researchers say they would make accelerators more cost effective for uses in many different scientific, medical and industrial fields.