Mankind has always had a love affair with power: So what could more seductive than the world's most powerful laser, capable of releasing a beam that's comparable to the energy released as a star explodes? Well, we haven't made a laser this mighty yet, but Hui Chen, a physicist from the Lawrence Livermore National Laboratory, and her colleagues are confident they could recreate such galactic events when the technology is available.
Using some of the most powerful lasers around, the team fired a laser beam at a sheet of gold foil and watched what popped out. The gold atoms produced a pair of particles when energized by the laser: one matter electron and one antimatter positron. Antimatter has similar properties to matter, but the electric charge is the opposite. So, a matter particle that is negative (e.g. electron) will have an antimatter partner particle that has the same mass but is positive (e.g. positron). A matter/antimatter collision creates so much energy that you can see high-energy gamma rays, and Chen's laboratory has created nearly a trillion particle pairs using this method.
The method that the laser beam uses to create matter/antimatter pairs is common to one of the universe's most energetic events: a gamma-ray burst (GRB). GRBs are a powerful explosion of energy that are emitted from extremely massive, energetic stellar objects, like black holes or exploding stars.
Perplexingly, no one knows which mechanisms are responsible for GRBs. Despite this, scientists feel confident that they could replicate GRBs in a lab with the right technology. And fortunately for scientists, the process that creates GRBs isn't thermal, that is to say, it doesn't involve any heat. So no one's going to burn away in a fiery, gamma-ray explosion when they turn on the laser.
"The mystery here is how do these [particle jets] convert their energy into high-energy non-thermal radiation?" Frederico Fiuza, one of the lead authors of the study, said. "We know these jets are formed, and we know bright, short bursts of gamma-rays are emitted. What links them?" Fiuza could soon find out. The team predicts that future lasers, for example National Ignition Facility’s Advanced Radiography Capability (ARC), will be powerful enough to create GRBs in the lab.
“Our simulations show that with upcoming laser systems, we can study how these energetic pairs of matter-antimatter convert their energy into radiation,” Fiuza said. “Confirming these predictions in an experiment would be extremely exciting.”
Image of 'Lasers' by Douglas Muth via Flickr