Traditional particle accelerators, which rely on electromagnetic fields to accelerate charged particles, are limited by radio frequency breakdown, restricting their acceleration gradient to 100 MeV/m. In contrast, compact laser accelerators, using plasma waves as the acceleration medium, have the potential to achieve acceleration gradients more than 1000 times higher (>100 GeV/m). This breakthrough could revolutionize fields such as particle and nuclear physics, laboratory astrophysics, high-energy-density science, and medical treatments. However, the technology for laser-accelerated ions is still far from reaching the energy levels of traditional accelerators. One of the main challenges lies in the relatively high inertia and slower movement of ions, which makes it difficult for them to keep pace with the laser-driven acceleration structure that propagates at the speed of light.

Recently, a novel ion acceleration method utilizing spatiotemporally shaped light with tunable velocity has been proposed. By controlling the propagation of the laser envelope to match the ion motion, this method enables continuous and efficient ion acceleration. Theoretically, shaped light with an intensity 〖10〗^20 w/cm^2 and a focal spot moving transversely to the laser propagation direction can accelerate ions to GeV/nucleon energies in a gas plasma, which is at least an order of magnitude higher than the maximum record of 100 MeV/nucleon for laser-based ion accelerators. Moreover, the criteria for successfully capturing and accelerating ions have been analytically derived using Hamiltonian analysis, and the robustness of this approach has been validated through multidimensional plasma kinetic simulations. This approach allows for compact high-repetition-rate production of high-energy ions, highlighting the capability of more generalized spatiotemporal pulse shaping to address open problems in plasma physics.

Figure 1：Schematic of an axisymmetric transverse flying focus, where solid lines represent light ray propagation and colors

 denote frequency components. The panel at right shows details near focus.

This work was jointly completed by Zheng Gong (ITP-CAS), Sida Cao (Stanford), John Palastro (Rochester) and Matthew Edwards (Stanford). The result was recently published in Phys. Rev. Lett. (https://doi.org/10.1103/PhysRevLett.133.265002).

Link：https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.133.265002

Contact:

Institute of Theoretical Physics, CAS

Zheng Gong

Email: zgong92@itp.ac.cn