Enhanced Ion Acceleration in Wire Array Targets
Joshua Luoma, Cornell University
Laser-accelerated ion sources are relevant to applications requiring localized heat deposition, ranging from fast-ignition fusion to cancer therapy. A variety of techniques for ion acceleration have been proposed in literature in pursuit of obtaining higher ion energy and flux. Target-normal sheath acceleration (TNSA) remains a reliable and robust acceleration method that greatly benefits from increasing laser absorption into the target. Adding micron-sized wire arrays to a target enables laser absorption near 90%, which in turn yields a high ion flux and large cut-off energies. Particle-in-cell simulations are used to investigate the physical mechanisms resulting in high coupling between the laser and wire target. The performance of wire arrays is compared with an ideal, uniform pre-plasma to demonstrate that inhomogeneous structures can play a pivotal role in enhancing ion acceleration.
*This research is supported by DOE NNSA LRGF under the cooperative agreement DE-NA0003960.