Compact Lasers Recreate Conditions Inside Stars

With compact lasers that use ultrashort laser pulses irradiating arrays of aligned nanowires, scientists are recreating the extreme conditions found in stars. Previously, this was only possible with large “stadium-sized” lasers, as the energy density contained in the center of a star is many billions of atmospheres, compared with the 1 atmosphere of pressure on Earth's surface.

Representation of the creation of ultra-high energy density matter by an intense laser pulse irradiation of an array of aligned nanowires. Courtesy of R. Hollinger and A. Beardall.

Researchers at Colorado State University (CSU) have accurately measured how deeply these extreme energies penetrate the nanostructures by monitoring the characteristic x-rays emitted from the nanowire array, in which the material composition changes with depth.

Numerical models validated by the experiments predict that increasing irradiation intensities to the highest levels made possible by today's ultrafast lasers could generate pressures to surpass those in the center of our sun.

The results open a path to obtaining unprecedented pressures in the laboratory with compact lasers. The work could open new inquiry into high energy density physics; how highly charged atoms behave in dense plasmas; and how light propagates at ultrahigh pressures, temperatures, and densities.

Creating matter in the ultra-high energy density regime could inform the study of laser-driven fusion — using lasers to drive controlled nuclear fusion reactions — and to further understanding of atomic processes in astrophysical and extreme laboratory environments.

The ability to create ultra-high energy density matter using smaller facilities is of great interest for making these extreme plasma regimes more accessible for fundamental studies and applications.

The CSU study has been published in the journal Science Advances (DOI: 10.1126/sciadv.1601558)