Hollow microspheres as targets for staged laser-driven proton acceleration

Abstract

A coated hollow core microsphere is introduced as a novel target in ultra-intense laser-matter interaction experiments. In particular, it facilitates staged laser-driven proton acceleration by combining conventional target normal sheath acceleration (TNSA), power recycling of hot laterally spreading electrons and staging in a very simple and cheap target geometry. During TNSA of protons from one area of the sphere surface, laterally spreading hot electrons form a charge wave. Due to the spherical geometry, this wave refocuses on the opposite side of the sphere, where an opening has been laser micromachined. This leads to a strong transient charge separation field being set up there, which can post-accelerate those TNSA protons passing through the hole at the right time. Experimentally, the feasibility of using such targets is demonstrated. A redistribution is encountered in the experimental proton energy spectra, as predicted by particle-in-cell simulations and attributed to transient fields set up by oscillating currents on the sphere surface.

13 pages, 7 figures

References in corpus (1)

• Dynamic Control of Laser Produced Proton Beams

Cited by in corpus (6)

• Ion acceleration by superintense laser-plasma interaction
• Towards Bright Gamma-Ray Flash Generation From Tailored Target Irradiated by Multi-Petawatt Laser
• Direction and divergence control of laser-driven energetic proton beam using a disk-solenoid target
• Origins of plateau formation in ion energy spectra under target normal sheath acceleration
• Prospects for laser-driven ion acceleration through controlled displacement of electrons by standing waves
• Energy partitioning and electron momentum distributions in intense laser-solid interactions