Phys.org reports that a newly published theoretical/computer-modeling study “suggests that the world’s most powerful lasers might finally crack the elusive physics behind some of the most extreme phenomena in the universe — gamma ray bursts, pulsar magnetospheres, and more.”
The study comes from an international team including researchers from Lawrence Berkeley National Laboratory and France’s Alternative Energies and Atomic Energy Commission (publishing in the journal Physical Review Letters.):
The team’s modeling study shows that petawatt (PW)-class lasers — juiced to even higher intensities via light-matter interactions — might provide a key to unlock the mysteries of the strong-field (SF) regime of quantum electrodynamics (QED). A petawatt is 1 times ten to the fifteenth power (that is, followed by 15 zeroes), or a quadrillion watts. The output of today’s most powerful lasers is measured in petawatts… “This is a powerful demonstration of how advanced simulation of complex systems can enable new paths for discovery science by integrating multiple physics processes — in this case, the laser interaction with a target and subsequent production of particles in a second target,” said ATAP Division Director Cameron Geddes….
The scheme consists of boosting the intensity of a petawatt laser pulse with a relativistic plasma mirror. Such a mirror can be formed when an ultrahigh intensity laser beam hits an optically polished solid target. Due to the high laser amplitude, the solid target is fully ionized, forming a dense plasma that reflects the incident light. At the same time the reflecting surface is actually moved by the intense laser field. As a result of that motion, part of the reflected laser pulse is temporally compressed and converted to a shorter wavelength by the Doppler effect. Radiation pressure from the laser gives this plasma mirror a natural curvature. This focuses the Doppler-boosted beam to much smaller spots, which can lead to extreme intensity gains — more than three orders of magnitude — where the Doppler-boosted laser beam is focused. The simulations indicate that a secondary target at this focus would give clear SF-QED signatures in actual experiments.
The study drew upon Berkeley Lab’s diverse scientific resources, including its WarpX simulation code, which was developed for modeling advanced particle accelerators under the auspices of the U.S. Department of Energy’s Exascale Computing Project… The discovery via WarpX of novel high-intensity laser-plasma interaction regimes could have benefits far beyond ideas for exploring strong-field quantum electrodynamics. These include the better understanding and design of plasma-based accelerators such as those being developed at the Berkeley Lab Laser Accelerator. More compact and less expensive than conventional accelerators of similar energy, they could eventually be game-changers in applications that range from extending the reach of high-energy physics and of penetrating photon sources for precision imaging, to implanting ions in semiconductors, treating cancer, developing new pharmaceuticals, and more.
“It is gratifying to be able to contribute to the validation of new, potentially very impactful ideas via the use of our novel algorithms and codes,” Vay said of the Berkeley Lab team’s contributions to the study. …read more
Source:: Slashdot