Interaction of Ultra-Intense Laser Pulses with Structured Targets in the Multi-Petawatt Regime

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This project will investigate a novel concept of particle acceleration by high power lasers. Ultra-powerful lasers are revolutionizing the field of plasma physics and leading to a number of exciting applications. One such application involves accelerating ion beams to velocities approaching the speed of light. Such relativistic beams can be used for applications as varied as treating tumors without damaging the surrounding tissues or producing neutrons for nuclear physics studies. While the basic idea of using radiative pressure of ultra-intense laser pulse to accelerate solid density targets may appear to be not much more challenging than using a blast of wind to move a sailboat across a lake, the details of laser-target interactions at such enormous laser intensities is quite complex. Many physical processes, including instabilities and explosions of electrically-charged targets, conspire to reduce the energy and directivity of the accelerated ions.This effort will overcome challenges to laser-driven ion acceleration by investigating a novel concept – Laser-Ion Lens and Accelerator (LILA) – that utilizes an ultra-thin solid target with non-uniform thickness propelled by a multi-petawatt (MPW) laser pulse. By utilizing targets that are thinner near the edge, LILA potentially enables simultaneous acceleration and focusing of the ion beam while preserving its small angular divergence. Physical properties of such converging plasma flows have not been previously investigated. Through the combination of theoretical modeling, nanofabrication, and experimentation at some of the premier laser facilities, this project will address a unique set of challenges, including modeling collective laser-plasma instabilities, understanding the behavior of quasi-neutral plasmas containing multiple ion species, optimization and fabrication of the designer target profiles, and reducing the achievable emittance of the beam. Proof-of principle experiments utilizing the existing and upcoming laser facilities will be designed and carried out. Extensive international collaborations at several MPW facilities in Europe and Asia will be established to achieve the key objectives of this project. The intellectual merit consists of developing novel computational tools for furthering our understanding of MPW laser interactions with structured solid targets, their stability, and suitability for a wide range of applications. The broader impacts include development of future compact laser-based relativistic ion accelerators, as well as training the next generation of scientists, including graduate and undergraduate students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.