Simulations Identify Requirements for LANL's High Intensity Laser Lab

Fig. 1. Cielo is a 1.37 petaflops capability-class supercomputer installed at LANL, funded by the US DOE NNSA for the ASC Program, built by Cray, Inc.

Fig. 2. Transverse profiles of the most energetic ions from VPIC modeling of laser-ion acceleration. The laser propagates inward from the center of each figure. Higher intensity shows wider beam divergence, more pronounced lobes.

A 3-day run on the ASC Cielo supercomputer (see Fig. 1) identified requirements for a future signature facility and enabled discovery science in laser-ion acceleration overturning decades of conventional wisdom. VPIC code simulations enabled identification of the facility functional requirements for the High Intensity Laser Laboratory (HILL) signature facility proposed at LANL. Called out in the Tri-Lab Facilities Roadmap, the HILL facility is synergistic with the Matter-Radiation Interactions in Extremes (MaRIE) signature facility being proposed at LANL. Originally envisioned as part of the full MaRIE project, HILL was submitted as a separate standalone facility. The program development for HILL would not have been possible without capability computing.

The project led to discovery science in which laser-generated ion beams were found to possess "lobes" whose angle depends on laser focus and intensity. VPIC code simulations of laser-ion acceleration at identical laser focus but different intensity show that higher intensity leads to wider lobes, as predicted by analytic theory. (See Fig. 2.) These calculations enabled: 1) a better definition of HILL "first experiments" using laser-generated particle beams, and 2) a proposal for an LDRD-DR project to use isochoric heating with laser-generated ion beams at the Trident laser facility to understand mix morphology in dense plasma. This work was published in a high-profile journal article.*

* Yin et al., Three-Dimensional Dynamics of Breakout Afterburner Ion Acceleration using High-Contrast Short-Pulse Laser and Nanoscale Targets, Phys. Rev. Lett. 107, 045003 (2011). http://prl.aps.org/abstract/PRL/v107/i4/e045003

(LA-UR 12-21969)