Washington: Researchers used laser beams 60,000 billion times more powerful than a laser pointer to recreate scaled supernova explosions in the laboratory as a way of investigating one of the most energetic events in the Universe.
Supernova explosions, triggered when the fuel within a star reignites or its core collapses, launch a detonation shock wave that sweeps through a few light years of space from the exploding star in just a few hundred years.
To investigate what may cause these peculiar shapes an international team led by Oxford University scientists (groups of Professor Gianluca Gregori of Oxford University`s Department of Physics and Professor Bell in Atomic and Laser Physics, and Professor Schekochihin in Theoretical Physics) has devised a method of studying supernova explosions in the laboratory instead of observing them in space.
To recreate a supernova explosion in the laboratory the team used the Vulcan laser facility at the UK`s Science and Technology Facilities Council`s Rutherford Appleton Lab. `Our team began by focusing three laser beams onto a carbon rod target, not much thicker than a strand of hair, in a low density gas-filled chamber,` said Ms Jena Meinecke an Oxford University graduate student, who headed the experimental efforts.
The enormous amount of heat generated more than a few million degrees Celsius by the laser caused the rod to explode creating a blast that expanded out through the low density gas. In the experiments the dense gas clumps or gas clouds that surround an exploding star were simulated by introducing a plastic grid to disturb the shock front.
`The experiment demonstrated that as the blast of the explosion passes through the grid it becomes irregular and turbulent just like the images from Cassiopeia,` said Professor Gregori.
`We found that the magnetic field is higher with the grid than without it. Since higher magnetic fields imply a more efficient generation of radio and X-ray photons, this result confirms that the idea that supernova explosions expand into uniformly distributed interstellar material isn`t always correct and it is consistent with both observations and numerical models of a shockwave passing through a `clumpy` medium.`