CHICAGO, Feb. 9 (Xinhua) -- A team of researchers found after intense experiments that by hitting electrons with an ultra-intense laser, they have stopped electrons as effectively as shooting them at a sheet of lead, which is called "radiation reaction."
Radiation reaction is interesting to physicists studying effects beyond "classical" physics, who were able to observe this radiation reaction by colliding a laser beam one quadrillion, or a billion million times brighter than light at the surface of the sun with a high-energy beam of electrons. The experiment used the Gemini laser at the Science and Technology Facilities Council's Central Laser Facility in the UK.
Photons of light that reflect from an object moving close to the speed of light have their energy increased. In the extreme conditions of this experiment, this shifts the reflected light from the visible part of the spectrum all the way up to high energy gamma rays. This effect let the researchers know when they had successfully collided the beams.
The collision of the two beams effectively creates incredibly strong magnetic fields, similar to the kinds of field observed around black holes and quasars.
"One of the main areas we're probing is these extremely strong fields, which are stronger than any fields on Earth," said University of Michigan (UM) physicist Alec Thomas, associate professor of nuclear engineering and radiological sciences.
The researchers were able to make the light so intense in the current experiment by focusing it to a very small spot and delivering all the energy in a very short duration.
To make the electron beam small enough to interact with the focused laser, the researchers used a technique called "laser wakefield acceleration."
The data from the experiment agree better with a theoretical model based on the principles of quantum electrodynamics, rather than Maxwell's equations, potentially providing some of the first evidence of previously untested quantum models.
The study has been published on February 7 in the journal Physical Review X.
