ABSTRACT: The interaction of ultrafast laser pulses of relativistic intensity with high aspect ratio nanostructures provides a unique combination of nearly complete optical absorption and enhanced energy penetration into near-solid density targets. This allows to volumetrically heat matter to an ultra-high-energy-density regime encountered in the center of stars and within the core of fusion capsules compressed by the world’s largest lasers. It also generates gigantic quasi-static electromagnetic fields that efficiently accelerate particles. Here we present an overview of the physics and applications of these dense relativistic plasmas that can be created with pulses of relatively modest energy from lasers that can operate at high repetition rate. Recent nanowire array experiments produced near-solid density plasmas with an extreme degree of ionization (eg. Au+72), converted ultrafast pulses of laser light into intense x-ray flashes with record efficiency, and accelerated ions to MeV energies efficiently driving micro-scale fusion reactions that generate flashes of quasi-monoenergetic neutrons. These plasmas also serve as a platform for advancing the understanding of atomic processes in extreme environments and open a possible new pathway to laser-driven fusion energy.

Work supported by the US Department of Energy Fusion Energy Sciences under Award No. DE-SC0024882 IFE-STAR, DOD VBFF ONR award N000142012842, using LaserNet US facilities supported by DOE

BIO: Jorge J. Rocca is a University Distinguished Professor in the Department of Electrical and Computer Engineering, and Department of Physics at Colorado State University. His research interests are in the physics and development of high-power lasers, x-ray lasers, and the study of ultra-intense laser-matter interactions including applications to fusion energy. His group has developed bright plasma-based soft x-ray lasers, including the first table-top soft x-ray laser, and demonstrated their application in several fields including nanotechnology and nanoscience, and in the diagnostics of dense plasmas. His group also developed ALEPH, one of the most powerful lasers in the world, that is accessible to users through LaserNet US, and kilowatt average power ultrafast solid-state lasers. He and his collaborators have shown that intense laser irradiation of ordered nanostructures creates an ultra-high energy density plasma environment that leads to extreme degree of ionization and micro-scale fusion. The results of his research are published in more than 300 peer review journal papers. He received the Arthur L. Schawlow Prize in Laser Science from the American Physical Society (APS) and the Willis E. Lamb Award for Laser Science and Quantum Optics. He was elected Fellow of the American Physical Society, OPTICA, and IEEE. Early in his career he was an NSF Presidential Young Investigator. He is a member of the National Academy of Engineering.

This seminar is sponsored by the Department of Applied Physics and the Ginzton Laboratory