Laserproton

Laserproton is a term used in high‐energy physics and laser science to refer to protons that are accelerated by intense laser pulses. The phenomenon is part of laser‐driven ion acceleration, which began in the early 1990s when powerful laser systems enabled the production of particle beams with energies far beyond those generated by conventional radio‑frequency accelerators. In a typical experimental setup, a short, high‑intensity laser (10^18–10^21 W cm^−2) is focused onto a solid target. The laser field ionizes the target surface, creating a hot plasma and an intense electric field that accelerates surface protons—usually from hydrocarbon contaminants—to tens of megaelectronvolts.

The basic mechanism of laserproton acceleration is often described by the Target Normal Sheath Acceleration (TNSA) model. In this model, hot electrons launched by the laser propagate through the target, leaving behind a sheath of negative charge that pulls protons forward. Alternative acceleration schemes include Radiation Pressure Acceleration, Breakout Afterburner, and Shock‑Driven Acceleration, each offering different beam qualities and energy ranges.

Laserproton beams have several potential applications. In medicine, they could enable compact hadrontherapy for cancer treatment, where precise energy deposition minimizes damage to healthy tissue. In materials science, they serve as pulsed ion sources for probing surface layers and inducing modifications. In nuclear physics, laserproton beams can initiate fusion reactions, providing a testbed for inertial confinement fusion concepts. Despite rapid progress, challenges remain in achieving high repetition rates, improving beam stability, and controlling energy spread. Current research focuses on laser system optimization, target engineering, and manipulation of electric fields to produce clinically and industrially viable proton sources.