Boffins build powerful yet 'table-top size' atom-smasher
Suitcase plasma cannon collider surfs on friggin LASERS
Forget about mounting your lasers on the nearest shark, what you really want is a laser plasma accelerator you can put on your kitchen table.
Scientists at the US Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have managed to create powerful electron beams from much, much, much smaller accelerators than before, which could be used as compact high-energy colliders for fundamental physics – doing the sort of research the Large Hadron Collider is doing right now.
The wee accelerators could also be used as "sources of intensely bright beams of light" for investigating new materials, biological structures and green chemistry. Or, presumably, for table-top disco lighting.
Wim Leemans, who heads the LOASIS program in Berkeley Lab's Accelerator and Fusion Research Division responsible for the research, uses the analogy of a (special, slightly slower) surfer riding a wave to explain how their accelerator is different.
Beaming a powerful laser pulse through plasma builds up strong electric fields between atomic nuclei and electrons and leaves a wake of waves. Some of the electrons then get caught up in the waves and accelerated to high energy.
According to Leemans, these electrons are surfers caught up in a tsunami. To help the surfers gain better control, scientists have been injecting electrons into the accelerating field, boosted by colliding laser pulses. These little guys try to catch the wave and then a different laser pulse excites the wave. Much like the surfer paddling alongside, then catching and riding the wave, the technique requires timing and synchronisation.
"But there's a third way of helping a surfer catch a wave,” Leemans says, "and that's by slowing the wave until even slow surfers can catch it – then increasing the speed of the wave."
To do this, the researchers introduced a jet of helium gas, which increases the density of the plasma, slowing the waves down. They then use the laser intensity to speed the whole lot back up again once the surfers are onboard
The LOASIS crew presented their research in the journal Nature Physics. ®
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